ABRET R.EEG.T. Exam — Questions and Answers

Question 1: Which EEG finding is considered a non-epileptiform abnormality that reflects cortical dysfunction ipsilateral to a structural lesion?

Lambda waves
Sleep spindles
Occipital dominant rhythm at 10 Hz
Focal polymorphic delta slowing (Correct answer)

Correct answer: Focal polymorphic delta slowing

Focal polymorphic delta activity indicates underlying structural or physiologic disruption of cortical neurons in that region and is not epileptiform.

Question 2: Which artifact appears as a regular, rhythmic waveform at the same frequency as the patient's heart rate?

Eye blink artifact
Glossokinetic artifact
Pulse artifact (ECG artifact) (Correct answer)
Electrode pop

Correct answer: Pulse artifact (ECG artifact)

Pulse artifact appears as rhythmic waveforms synchronous with the cardiac cycle, caused by electrode placement over a pulsating blood vessel or by ballistocardiographic effect.

Question 3: A patient undergoing an EEG displays rhythmic 8-13 Hz activity over the occipital regions that attenuates with eye-opening. This activity is primarily modulated by which subcortical structure?

Cerebellum
Basal Ganglia
Hippocampus
Thalamus (Correct answer)

Correct answer: Thalamus

The posterior dominant alpha rhythm, an 8-13 Hz activity seen in relaxed wakefulness, is generated through corticothalamic circuits. The thalamus acts as a pacemaker and gatekeeper, synchronizing cortical activity to produce these characteristic rhythms. The hippocampus is involved in memory, the basal ganglia in motor control, and the cerebellum in coordination; they are not the primary modulators of the alpha rhythm.

Question 4: On a density spectral array (DSA) in a patient following subarachnoid hemorrhage, which finding would raise concern for delayed cerebral ischemia (DCI)?

Intermittent increase in beta power bilaterally following sedation boluses
Appearance of sleep spindles bilaterally during nighttime hours
Progressive loss of alpha and sigma power with increase in delta power over the affected hemisphere (Correct answer)
Stable alpha-frequency power bilaterally over 72 hours

Correct answer: Progressive loss of alpha and sigma power with increase in delta power over the affected hemisphere

DCI produces neuronal dysfunction that manifests on the DSA as a loss of faster frequencies (alpha 8–13 Hz, sigma 12–15 Hz) and an increase in slow delta power over the at-risk hemisphere. This qEEG signature can precede clinical deterioration by hours, making continuous trend monitoring valuable for early DCI detection in subarachnoid hemorrhage patients.

Question 5: Electrode bridging occurs when:

Two nearby electrodes are electrically connected by excess conductive gel, producing nearly identical waveforms (Correct answer)
The ground electrode fails during recording
Digital filters create artificial similarities between channels
An electrode falls off and makes contact with a metal surface

Correct answer: Two nearby electrodes are electrically connected by excess conductive gel, producing nearly identical waveforms

Electrode bridging occurs when excessive conductive gel spreads between adjacent electrodes, creating a low-resistance pathway that makes both electrodes record essentially the same signal, reducing spatial resolution.

Question 6: A 6-Hz spike-and-wave burst lasting less than 2 seconds seen in a drowsy young adult is most consistent with:

Juvenile myoclonic epilepsy ictal discharge
Phantom spike-and-wave (benign variant) (Correct answer)
Temporal lobe seizure onset
Absence status epilepticus

Correct answer: Phantom spike-and-wave (benign variant)

The 6-Hz 'phantom' spike-and-wave is a benign normal variant in drowsy young adults and should not be misinterpreted as pathological epileptiform activity.

Question 7: What is the purpose of the notch filter in EEG recording?

To boost low-frequency signals for better visualization
To eliminate all frequencies above 30 Hz
To selectively attenuate 60 Hz (or 50 Hz) power line interference while preserving surrounding frequencies (Correct answer)
To amplify signals at a specific frequency

Correct answer: To selectively attenuate 60 Hz (or 50 Hz) power line interference while preserving surrounding frequencies

The notch filter is a band-reject filter designed to selectively remove power line interference (60 Hz in North America, 50 Hz in other regions) while minimally affecting adjacent frequencies.

Question 8: What is the best approach when an artifact cannot be eliminated during recording?

Document the artifact's characteristics, suspected source, and affected channels in the technical notes while continuing the recording (Correct answer)
Digitally delete the artifact from the record
Ignore it as artifacts are expected in all recordings
Stop the recording and reschedule the study

Correct answer: Document the artifact's characteristics, suspected source, and affected channels in the technical notes while continuing the recording

When artifacts cannot be eliminated, the technologist should thoroughly document them in the technical notes (type, source, affected channels, timing) while continuing the recording, providing the interpreter with essential information for accurate reading.

Question 9: What is the standard infection control practice for disinfecting non-disposable surface cup electrodes after use on a patient with an intact scalp and no known infectious diseases?

Placing the electrodes in an autoclave for steam sterilization.
Mechanically cleaning the electrodes, then immersing them in an appropriate intermediate-level disinfectant. (Correct answer)
Wiping the electrodes with a 70% isopropyl alcohol pad.
Soaking the electrodes in hot, soapy water for 30 minutes.

Correct answer: Mechanically cleaning the electrodes, then immersing them in an appropriate intermediate-level disinfectant.

Standard procedure requires a two-step process: first, mechanically cleaning the electrode with a brush or abrasive paste to remove all conductive media and organic material, followed by immersion in an EPA-registered, hospital-grade intermediate-level disinfectant for the manufacturer-recommended time. Wiping with alcohol is insufficient, and autoclaving would damage the electrodes. Soapy water alone does not provide disinfection.

Question 10: Waves that are regular and resemble sine waves.

Sinusoidal (Correct answer)
Diphasic
Polyphasic
Ictal

Correct answer: Sinusoidal

Regular waves that mimic sine waves are called sinusoidal waves. They repeat in a smooth, regular rhythm with a constant amplitude and frequency. Numerous natural phenomena, including sound, electromagnetic, and water waves, frequently exhibit sinusoidal waves. The best phrase, among those provided, to characterize regular waves that approximate sine waves is sinusoidal.

Question 11: Which electrode site is used as the nasion landmark in the 10-20 measurement system?

The glabella above the nose
The bridge of the nose between the eyes (Correct answer)
The tip of the nose
The center of the forehead

Correct answer: The bridge of the nose between the eyes

The nasion is the depression at the bridge of the nose between the eyes and serves as the anterior skull landmark for 10-20 measurements.

Question 12: In juvenile myoclonic epilepsy (JME), the EEG hallmark is polyspike-and-wave discharges typically at which frequency?

3 Hz
1–2 Hz
4–6 Hz (Correct answer)
10–12 Hz

Correct answer: 4–6 Hz

JME is characterized by generalized polyspike-and-wave complexes at 4–6 Hz, typically maximal in the morning and activated by sleep deprivation.

Question 13: Which EEG pattern is characterized by bilateral synchronous 3-Hz spike-and-wave discharges that are typically enhanced by hyperventilation?

Juvenile myoclonic epilepsy
Lennox-Gastaut syndrome
Dravet syndrome
Childhood absence epilepsy (Correct answer)

Correct answer: Childhood absence epilepsy

Childhood absence epilepsy classically produces bilateral synchronous 3-Hz spike-and-wave discharges that are strongly activated by hyperventilation.

Question 14: Tibial nerve SSEPs are primarily used to monitor which spinal cord tracts during surgery?

Rubrospinal tracts
Anterior corticospinal tracts
Dorsal column–medial lemniscus pathway (Correct answer)
Spinothalamic tracts

Correct answer: Dorsal column–medial lemniscus pathway

Tibial nerve SSEPs ascend via the posterior (dorsal) columns carrying proprioception and fine touch, so they specifically monitor the dorsal column–medial lemniscal pathway.

Question 15: Subclinical rhythmic electrographic discharges of adults (SREDA) is a rare benign pattern that mimics:

Normal posterior dominant rhythm
Generalized periodic discharges
Sleep spindles in Stage N2
Electrographic seizure activity with rhythmic theta over widespread or posterior regions (Correct answer)

Correct answer: Electrographic seizure activity with rhythmic theta over widespread or posterior regions

SREDA is a rare benign EEG pattern that closely mimics seizure activity, consisting of sudden-onset widespread or posterior-dominant rhythmic theta (5-7 Hz) that evolves in frequency, potentially leading to misdiagnosis of epilepsy.

Question 16: Photomyogenic (photomyoclonic) response, which can mimic a photoparoxysmal response, differs in that it:

Begins with a posterior predominance
Is frontally predominant muscle artifact time-locked to each flash (Correct answer)
Outlasts the stimulus train
Consists of generalized spike-wave discharges

Correct answer: Is frontally predominant muscle artifact time-locked to each flash

Photomyogenic response is a muscle artifact (frontalis/orbicularis) synchronized to each photic flash, whereas photoparoxysmal response is a true cerebral epileptiform discharge that may outlast the stimulus.

Question 17: An EEG technologist is performing a biological calibration. The patient is asked to open and close their eyes, look left and right, and clench their jaw. What is the primary purpose of this procedure?

To warm up the EEG amplifiers and ensure they are functioning.
To assess the patient's level of cooperation before starting the recording.
To measure the baseline impedance of the scalp electrodes.
To verify the integrity of the recording system by generating physiological artifacts and confirming correct channel derivations. (Correct answer)

Correct answer: To verify the integrity of the recording system by generating physiological artifacts and confirming correct channel derivations.

Biological calibration (bio-cal) is essential to ensure the entire recording pathway is functioning correctly. By having the patient perform specific actions that are known to create distinct physiological artifacts (like eye movements and muscle tension), the technologist can confirm that electrodes are correctly placed and connected to the appropriate channels in the montage, and that the amplifiers are displaying these signals as expected.

Question 18: A 9-month-old infant is evaluated for clusters of sudden, brief flexor spasms. The interictal EEG shows a chaotic, high-voltage, and disorganized pattern of asynchronous slow waves and multifocal spikes. Which of the following terms best describes this EEG pattern?

Triphasic waves
Hypsarrhythmia (Correct answer)
Slow spike-and-wave
Burst-suppression

Correct answer: Hypsarrhythmia

Hypsarrhythmia is the characteristic interictal EEG pattern associated with Infantile Spasms (West Syndrome). It is defined by its disorganized, high-amplitude, and chaotic appearance, with a mix of random slow waves and multifocal spikes.

Question 19: According to American Clinical Neurophysiology Society (ACNS) and AAN guidelines, what is the minimum sensitivity required when recording an EEG to assess for electrocerebral inactivity (ECI)?

7 µV/mm
5 µV/mm
2 µV/mm (Correct answer)
10 µV/mm

Correct answer: 2 µV/mm

AAN/ACNS guidelines require a minimum sensitivity of 2 µV/mm (equivalent to ≤2 µV/mm) during ECI recordings so that very low-amplitude cerebral activity is not missed. Standard clinical sensitivity (7 µV/mm) would be insufficiently sensitive for this purpose.

Question 20: An EEG technologist is setting up for a routine adult EEG. According to the International 10-20 System, what are the four primary anatomical landmarks used to ensure standardized and proportional electrode placement?

Nasion, inion, and both preauricular points (Correct answer)
Nasion, inion, and both mastoid processes
Vertex, inion, and both zygomatic arches
Nasion, vertex, and both temporal lobes

Correct answer: Nasion, inion, and both preauricular points

The International 10-20 System relies on four key anatomical landmarks for its measurements: the nasion (bridge of the nose), the inion (bony prominence at the back of the skull), and the left and right preauricular points (depressions just in front of the ears). These points form the basis for all subsequent measurements, ensuring that electrode placement is proportional to the patient's head size and shape.

Question 21: During an EEG-recorded absence seizure, the 3 Hz spike-and-wave discharge is generated by abnormal oscillations between the cortex and which structure?

Thalamus (Correct answer)
Basal ganglia
Hippocampus
Cerebellum

Correct answer: Thalamus

Absence seizures arise from abnormal thalamocortical resonance, with cortical and thalamic circuits entraining at ~3 Hz spike-and-wave frequency.

Question 22: A patient's EEG shows slow (1–2.5 Hz) spike-and-wave complexes during sleep alongside atonic and tonic seizures. Which syndrome does this pattern most suggest?

Lennox-Gastaut syndrome (Correct answer)
Dravet syndrome
Angelman syndrome
West syndrome

Correct answer: Lennox-Gastaut syndrome

Lennox-Gastaut syndrome is defined by slow (1–2.5 Hz) spike-and-wave, multiple seizure types including atonic and tonic, and intellectual disability.

Question 23: During polysomnography, the minimum duration of a K-complex to be scored as such is:

0.25 seconds
0.5 seconds (Correct answer)
2.0 seconds
1.0 second

Correct answer: 0.5 seconds

Per AASM scoring rules, a K-complex must have a duration of ≥0.5 seconds to be distinguished from other sharp transients.

Question 24: Slow, sinusoidal, high-amplitude waves that wax and wane over frontal electrodes in a drowsy, diaphoretic patient are most characteristic of:

Muscle artifact
Eye movement artifact
Sweat artifact (Correct answer)
Delta slowing

Correct answer: Sweat artifact

Sweat artifact produces slow (< 1 Hz), large-amplitude sinusoidal waves predominantly over frontal regions due to sweat gland activity.

Question 25: A technologist changes the sensitivity setting from 7 µV/mm to 10 µV/mm. How will this affect the appearance of a 70 µV spike on the display?

The spike will become wider.
The spike's appearance will not change.
The spike will appear taller.
The spike will appear shorter. (Correct answer)

Correct answer: The spike will appear shorter.

Sensitivity is the ratio of input voltage to the pen or trace deflection (µV/mm). At 7 µV/mm, a 70 µV spike would cause a 10 mm deflection (70 µV / 7 µV/mm = 10 mm). When the sensitivity is changed to 10 µV/mm, the same 70 µV spike will cause a 7 mm deflection (70 µV / 10 µV/mm = 7 mm). Therefore, increasing the numerical value of the sensitivity setting decreases the amplitude of the displayed waveform, making it appear shorter.

Question 26: What does a referential montage compare each electrode to?

The ground electrode
The opposite hemisphere electrode
A common reference electrode (Correct answer)
The adjacent electrode

Correct answer: A common reference electrode

In a referential montage, each active electrode is compared to a single common reference electrode, often placed at the ear or linked mastoids.

Question 27: A 24-hour ambulatory EEG uses a sample rate of 256 Hz. What is the highest frequency that can be faithfully represented according to the Nyquist theorem?

256 Hz
64 Hz
128 Hz (Correct answer)
512 Hz

Correct answer: 128 Hz

The Nyquist theorem states the maximum representable frequency is half the sampling rate, so 256 Hz ÷ 2 = 128 Hz.

Question 28: Sleep deprivation before an EEG is primarily used to:

Shorten the overall recording time
Improve electrode impedance
Reduce muscle artifact throughout the recording
Increase the likelihood of recording epileptiform discharges (Correct answer)

Correct answer: Increase the likelihood of recording epileptiform discharges

Sleep deprivation is an activation procedure that increases the yield of detecting epileptiform abnormalities by promoting drowsiness and sleep, states in which interictal discharges are more likely to appear.

Question 29: AAN guidelines for ECI recordings require a minimum interelectrode distance of at least how many centimeters to avoid missing low-amplitude activity between nearby electrodes?

10 cm (Correct answer)
15 cm
20 cm
5 cm

Correct answer: 10 cm

A minimum interelectrode distance of 10 cm is mandated so that small potential differences across brain tissue are not masked by electrodes placed too closely together. Shorter distances increase the risk of amplitude cancellation and may falsely suggest ECI.

Question 30: Which technical factor most directly degrades SSEP and BAEP signal quality by introducing 60 Hz noise and poor signal-to-noise ratio?

High patient body temperature
Low number of trials averaged
Slow stimulus repetition rate
High electrode impedance (Correct answer)

Correct answer: High electrode impedance

High electrode impedance increases susceptibility to capacitively coupled electrical interference (60 Hz), which obscures the small far-field potentials and cannot be fully corrected by averaging.

Question 31: A technologist uses a short-time constant (high-pass filter increase) to reduce which type of artifact?

Electrode pop
Muscle artifact
60 Hz line noise
Slow sweat artifact (Correct answer)

Correct answer: Slow sweat artifact

Increasing the high-pass (low frequency) filter shortens the time constant and attenuates slow, DC-shift sweat artifact.

Question 32: An EEG technologist is asked by a pharmaceutical company representative to share de-identified EEG recordings for research. What must occur before any sharing?

The technologist can share data if the patient's name is removed from the file header
Written approval from the facility's IRB or privacy officer and a data use agreement must be in place (Correct answer)
Verbal approval from the ordering physician is sufficient
The technologist may share de-identified data freely since there is no PHI involved

Correct answer: Written approval from the facility's IRB or privacy officer and a data use agreement must be in place

Sharing patient data for research, even de-identified, requires institutional oversight through an IRB and a formal data use agreement.

Question 33: During hyperventilation in a normal adult, what EEG change is expected?

Complete EEG suppression
Increased beta activity
Increased high-amplitude slow activity (Correct answer)
Onset of sleep spindles

Correct answer: Increased high-amplitude slow activity

Hyperventilation causes cerebral vasoconstriction and hypocapnia, producing diffuse high-amplitude slow (delta/theta) activity in normal subjects.

Question 34: The standard recommended duration of the hyperventilation activation procedure in adults is:

2 minutes
1 minute
5 minutes
3 minutes (Correct answer)

Correct answer: 3 minutes

ACNS guidelines recommend 3 minutes of hyperventilation followed by at least 1 minute of post-HV recording to capture delayed responses.

Question 35: Sleep spindles are a hallmark of which stage of sleep?

Stage N1 (drowsiness)
Stage N3 (deep slow wave sleep)
Stage N2 sleep (Correct answer)
REM sleep

Correct answer: Stage N2 sleep

Sleep spindles (11-16 Hz bursts lasting 0.5-2 seconds) are the defining feature of Stage N2 sleep. They are generated by thalamic reticular nucleus oscillations and are best seen over central regions.

Question 36: When measuring for electrode placement, the preauricular point is identified as:

The depression anterior to the tragus of the ear at the root of the zygoma (Correct answer)
The tip of the ear lobe
The external auditory meatus
The most prominent point of the mastoid bone

Correct answer: The depression anterior to the tragus of the ear at the root of the zygoma

The preauricular point is the small depression just in front of the tragus at the root of the zygomatic arch, serving as a key landmark for measuring transverse electrode distances in the 10-20 system.

Question 37: When a patient on ambulatory EEG reports a suspected seizure event via the event button but the recording shows no ictal activity, the MOST likely explanation is:

The button was pressed too late after the event ended
Electrode impedance was too high during the event
Equipment malfunction caused signal dropout
The event was a non-epileptic psychogenic episode (Correct answer)

Correct answer: The event was a non-epileptic psychogenic episode

Non-epileptic psychogenic events (PNES) are a common finding when patient-reported events lack EEG correlate during ambulatory monitoring.

Question 38: An EEG recording of a relaxed, awake adult with eyes closed shows a prominent 8-13 Hz rhythm in the occipital regions. This rhythm attenuates with eye opening. Which of the following best identifies this waveform?

Beta rhythm
Theta rhythm
Alpha rhythm (Correct answer)
Mu rhythm

Correct answer: Alpha rhythm

The posterior dominant alpha rhythm is the hallmark of a normal, relaxed, awake adult EEG with eyes closed. It is characterized by its frequency of 8-13 Hz, posterior location (maximal in the occipital regions), and its attenuation or blocking with eye opening or mental effort.

Question 39: On a neonatal EEG, which feature best distinguishes a seizure discharge from a normal sharp transient?

Evolution in frequency, amplitude, or spatial distribution over time (Correct answer)
Presence of a post-ictal suppression lasting 1 second
Occurrence during active sleep
Amplitude exceeding 100 µV

Correct answer: Evolution in frequency, amplitude, or spatial distribution over time

Neonatal seizures are defined by electrographic evolution — a clear change in frequency, morphology, or field — rather than by a fixed amplitude or sleep-state rule.

Question 40: In a healthy, awake adult, the presence of excessive, generalized, and persistent theta activity (4-7 Hz) would most likely be interpreted as:

A normal posterior dominant rhythm.
A normal variant during hyperventilation.
Evidence of cerebral dysfunction. (Correct answer)
An indicator of deep relaxation.

Correct answer: Evidence of cerebral dysfunction.

While small amounts of theta activity can be normal, especially during drowsiness, excessive and persistent generalized theta activity in an awake adult is considered abnormal. It is a nonspecific indicator of generalized cerebral dysfunction or encephalopathy.

Question 41: Which montage change is most useful for confirming that a suspected artifact is truly artifactual rather than cerebral?

Decreasing the time base
Switching between bipolar and referential montages (Correct answer)
Increasing the sensitivity
Switching from average to Laplacian reference

Correct answer: Switching between bipolar and referential montages

True cerebral activity maintains consistent field distributions across montages, while artifacts often appear or disappear inconsistently when the montage is changed.

Question 42: What minimum area of synchronously active cortex is typically required to produce a detectable signal on scalp EEG?

100 cm²
25 cm²
1 cm²
6 cm² (Correct answer)

Correct answer: 6 cm²

Approximately 6 cm² (some estimates range from 6-10 cm²) of synchronously active cortex is needed to generate sufficient electrical potential to be detected through the skull, meninges, and scalp by surface electrodes.

Question 43: In a bipolar longitudinal montage, what is the typical chain order for the left hemisphere?

Fp1-F7-T3-T5-O1
O1-P3-C3-F3-Fp1
F3-C3-P3-T3-O1
Fp1-F3-C3-P3-O1 (Correct answer)

Correct answer: Fp1-F3-C3-P3-O1

The standard longitudinal bipolar (double banana) chain runs from front to back: Fp1-F3-C3-P3-O1 for the left parasagittal chain.

Question 44: Which ascending arousal pathway originating in the locus coeruleus modulates cortical excitability and EEG background through norepinephrine release?

Dorsal noradrenergic bundle (Correct answer)
Nigrostriatal pathway
Raphe-cortical serotonin pathway
Mesolimbic dopamine pathway

Correct answer: Dorsal noradrenergic bundle

The dorsal noradrenergic bundle from the locus coeruleus projects widely to cortex, modulating neuronal excitability and promoting EEG desynchronization during alertness.

Question 45: During a brain death EEG, the technologist applies a painful stimulus (sternal rub) and shines a bright light in the patient's eyes. The purpose of these maneuvers is to assess:

Activation of epileptiform discharges
Photic driving response at low frequencies
EEG reactivity to external stimulation (Correct answer)
Muscle artifact contamination of the tracing

Correct answer: EEG reactivity to external stimulation

Reactivity testing is a required component of an ECI study. Any change in the EEG in response to painful, auditory, or visual stimulation indicates residual cortical function and rules out true ECI. The absence of reactivity, combined with flat tracing at high sensitivity, supports the ECI determination.

Question 46: Electrocerebral inactivity (ECI) on EEG requires that no cerebral electrical activity exceed what amplitude threshold?

20 µV
2 µV (Correct answer)
10 µV
5 µV

Correct answer: 2 µV

ECI is defined as no electrical activity over 2 µV recorded with electrode impedances under 10 kΩ using high-sensitivity settings and standard interelectrode distances.

Question 47: What is the primary waveform of clinical interest in a pattern reversal visual evoked potential (VEP)?

P100 (Correct answer)
N75
P200
N145

Correct answer: P100

The P100 is the large positive peak occurring around 100 ms, generated in primary visual cortex, and is the most reliable and clinically significant component of the pattern reversal VEP.

Question 48: Approximately how many stimulus repetitions (averages) are typically needed to obtain a reliable, reproducible BAEP waveform?

300–500
5000–10000
50–200
1000–2000 (Correct answer)

Correct answer: 1000–2000

Because the BAEP signal amplitude is only about 0.1–1 µV, averaging 1000–2000 responses is required to achieve an adequate signal-to-noise ratio and clearly resolve all five waves.

Question 49: An 82-year-old patient with severe dementia is brought from a nursing home for a routine EEG. The patient is unable to state their name or understand the procedure. Who is the most appropriate individual to provide informed consent for the EEG?

The patient's legally authorized representative or next of kin. (Correct answer)
The patient, after the technologist explains in very simple terms.
The ordering neurologist who determined the procedure was necessary.
The registered nurse who accompanied the patient from the facility.

Correct answer: The patient's legally authorized representative or next of kin.

When a patient lacks the cognitive capacity to make an informed decision, consent must be obtained from their legally authorized representative (e.g., a person with durable power of attorney for healthcare or a legal guardian). This individual is empowered to make healthcare decisions on the patient's behalf. The ordering physician determines medical necessity but cannot provide consent for the patient, and an accompanying nurse typically does not have legal authority to consent unless they are also the legal representative.

Question 50: An EEG on a 10-year-old child shows high-amplitude, diphasic sharp waves that occur independently over the centrotemporal regions (C3/T3 and C4/T4). The discharges become significantly more frequent during drowsiness and sleep. This pattern is pathognomonic for which epilepsy syndrome?

Juvenile Myoclonic Epilepsy (JME)
Lennox-Gastaut Syndrome (LGS)
Self-limited Epilepsy with Centrotemporal Spikes (SeLECTS) (Correct answer)
Childhood Absence Epilepsy (CAE)

Correct answer: Self-limited Epilepsy with Centrotemporal Spikes (SeLECTS)

Self-limited Epilepsy with Centrotemporal Spikes (SeLECTS), formerly known as Benign Rolandic Epilepsy, is characterized by these specific centrotemporal spikes, which show a marked increase during sleep. The location of the discharges is key to this diagnosis.

Question 51: An EEG electrode placed at C3, according to the International 10-20 System, primarily records activity from which cortical region?

The primary visual cortex (Brodmann area 17)
The primary motor and somatosensory cortex (Brodmann areas 4, 1, 2, 3) (Correct answer)
The prefrontal cortex (Brodmann areas 9, 10)
The primary auditory cortex (Brodmann areas 41, 42)

Correct answer: The primary motor and somatosensory cortex (Brodmann areas 4, 1, 2, 3)

The central electrodes (C3, Cz, C4) are situated over the Rolandic fissure (central sulcus). This area encompasses the precentral gyrus (primary motor cortex, Brodmann area 4) and the postcentral gyrus (primary somatosensory cortex, Brodmann areas 1, 2, and 3).

Question 52: In a healthy 3-year-old child, the posterior dominant rhythm (PDR) during relaxed wakefulness with eyes closed is expected to have a frequency of approximately:

6-7 Hz
10-12 Hz
4-5 Hz
8-9 Hz (Correct answer)

Correct answer: 8-9 Hz

The posterior dominant rhythm (PDR), or alpha rhythm, matures with age. It begins around 3-4 Hz at a few months of age and should reach the alpha frequency range of 8 Hz by approximately 3 years of age. [2] A PDR of 4-5 Hz would be too slow for a 3-year-old, while 10-12 Hz is more typical of an older child or adult. 6-7 Hz would be expected around 12 months of age.

Question 53: Positive occipital sharp transients of sleep (POSTS) are a normal variant that appear during which sleep stage?

Stage N2 and N3
Stage N2, N3, and sometimes REM (Correct answer)
REM sleep only
Stage N1 only

Correct answer: Stage N2, N3, and sometimes REM

POSTS are surface-positive sharp transients over the occipital regions seen in stage N2, N3, and sometimes REM sleep.

Question 54: A patient has recurrent brief lapses with 3-Hz spike-and-wave that are abruptly terminated by photic stimulation. This response pattern is called:

Fixation-off sensitivity
Scotosensitivity
Photomyogenic response
Photoparoxysmal response (Correct answer)

Correct answer: Photoparoxysmal response

A photoparoxysmal response refers to generalized epileptiform discharges (spike-and-wave) triggered by intermittent photic stimulation, distinct from the non-epileptiform photomyogenic response.

Question 55: Which of the following is the LEAST likely cause of persistent 60 Hz electrical interference in an EEG recording?

Unbalanced electrode impedances, with one being significantly higher than the others.
The patient's rhythmic chewing or teeth clenching. (Correct answer)
A frayed power cord on the EEG machine or patient's bed.
A nearby unplugged piece of medical equipment in the room.

Correct answer: The patient's rhythmic chewing or teeth clenching.

Chewing and teeth clenching produce electromyographic (EMG) artifact, which is high-frequency but is generated by muscle activity and is not locked to the 60 Hz power line frequency. The other options are all common sources of electrical interference that can introduce 60 Hz noise into a recording.

Question 56: On a qEEG trend panel, a sudden increase in the seizure probability (SP) line coincides with a visible change on the rhythmic run detector. The NEXT step for the EEG technologist should be:

Increase the high-frequency filter setting to reduce muscle artifact
Decrease the epoch length to improve temporal resolution of the trend
Review the corresponding raw EEG segment to confirm whether the trend reflects a true electrographic seizure or artifact (Correct answer)
Immediately notify the physician that the patient is in status epilepticus

Correct answer: Review the corresponding raw EEG segment to confirm whether the trend reflects a true electrographic seizure or artifact

qEEG trend algorithms are sensitive but not specific — they detect rhythmic and high-amplitude events but cannot distinguish between a true electrographic seizure and chewing artifact, electrode pop, or patient movement. The mandatory next step is always to review the raw EEG underlying the flagged epoch before any clinical action is taken.

Question 57: What is the purpose of recording a period of wakefulness with eyes open and eyes closed before activation procedures?

To establish the baseline EEG background including posterior dominant rhythm frequency, reactivity, and symmetry (Correct answer)
To calibrate the photic stimulator
To reduce the total recording time needed
To test the patient's visual acuity

Correct answer: To establish the baseline EEG background including posterior dominant rhythm frequency, reactivity, and symmetry

Baseline awake recording with eyes open and closed establishes the posterior dominant rhythm (frequency, amplitude, symmetry, reactivity), identifies any focal or generalized abnormalities, and provides comparison for interpreting changes during activation procedures.

Question 58: Lennox-Gastaut syndrome is characterized by which EEG pattern during wakefulness?

Normal background with occasional vertex waves
Focal temporal sharp waves
3 Hz generalized spike-and-wave
Slow spike-and-wave complexes at 1.5-2.5 Hz (Correct answer)

Correct answer: Slow spike-and-wave complexes at 1.5-2.5 Hz

Lennox-Gastaut syndrome features slow (<3 Hz) generalized spike-and-wave complexes during wakefulness and generalized paroxysmal fast activity during sleep, along with multiple seizure types.

Question 59: Which medication commonly produces diffuse beta activity as a non-epileptiform EEG abnormality?

Benzodiazepines (Correct answer)
Levetiracetam
Phenytoin
Haloperidol

Correct answer: Benzodiazepines

Benzodiazepines and barbiturates classically increase diffuse beta activity (>13 Hz), which is a drug effect rather than a pathological finding.

Question 60: Spectral edge frequency (SEF95) is defined as the frequency below which what percentage of the total EEG spectral power is contained?

90%
50%
75%
95% (Correct answer)

Correct answer: 95%

SEF95 is the frequency at or below which 95% of the total spectral power lies. It is a single-number summary of the 'upper edge' of EEG activity and is used in anesthesia monitoring and ICU trend analysis to track shifts in dominant frequencies over time. A falling SEF95 indicates slowing of brain activity.

Question 61: What property of pyramidal neurons makes them the primary generators of scalp-recorded EEG signals rather than stellate cells?

Greater absolute membrane potential
Higher firing rates
Open-field geometry with parallel dendrites perpendicular to cortical surface (Correct answer)
Larger action potential amplitude

Correct answer: Open-field geometry with parallel dendrites perpendicular to cortical surface

Pyramidal neurons are arranged in parallel columns perpendicular to the cortical surface, creating open-field dipoles whose extracellular currents summate and propagate to the scalp.

Question 62: Which of the following is a contraindication for performing hyperventilation during an EEG?

Age over 40 years
Recent cerebrovascular accident (Correct answer)
History of febrile seizures
History of generalized tonic-clonic seizures

Correct answer: Recent cerebrovascular accident

Recent stroke is a contraindication for hyperventilation because the resulting hypocapnia and cerebral vasoconstriction could worsen ischemia in vulnerable brain tissue.

Question 63: Which BAEP wave is generated by the auditory nerve (cranial nerve VIII) and is commonly absent in acoustic neuroma?

Wave I only (Correct answer)
Wave III
Wave II
Wave V

Correct answer: Wave I only

Wave I is generated by the distal auditory nerve; its absence alongside preserved waves generated more centrally suggests a peripheral CN VIII lesion such as acoustic neuroma.

Question 64: Which cortical cell type is the primary generator of EEG signals recorded at the scalp?

Stellate interneurons
Purkinje cells of the cerebellum
Pyramidal neurons in cortical layers III and V (Correct answer)
Motor neurons of the precentral gyrus

Correct answer: Pyramidal neurons in cortical layers III and V

Pyramidal neurons are the primary generators of scalp EEG because their elongated apical dendrites are oriented perpendicular to the cortical surface, creating open electrical fields that summate and can be detected at the scalp.

Question 65: The mu rhythm, typically recorded over the central regions, is characterized by:

1-3 Hz delta activity that increases with movement
Theta bursts during hyperventilation
15-30 Hz beta activity maximal during sleep
An arch-shaped 8-13 Hz rhythm that attenuates with contralateral limb movement or movement planning (Correct answer)

Correct answer: An arch-shaped 8-13 Hz rhythm that attenuates with contralateral limb movement or movement planning

The mu rhythm is an 8-13 Hz arch-shaped (wicket-like) rhythm over the central (sensorimotor) cortex that blocks with contralateral movement, motor planning, or even observation of movement, reflecting sensorimotor cortex function.

Question 66: When reviewing an ambulatory EEG, the technologist notices that channels Fp1 and Fp2 show high-amplitude slow waves every 3–4 seconds throughout the entire recording. The MOST likely cause is:

Delta slowing from a frontal mass lesion
Frontal lobe epilepsy
Electrode gel drying causing increased impedance artifact
Blink artifact from the frontopolar electrode location (Correct answer)

Correct answer: Blink artifact from the frontopolar electrode location

Blink artifact consistently appears at Fp1 and Fp2 as large slow deflections due to the corneoretinal dipole movement directly beneath these frontopolar electrodes.

Question 67: TIRDA (Temporal Intermittent Rhythmic Delta Activity) is considered a non-epileptiform abnormality but is clinically significant because it is associated with which condition?

Normal aging
Frontal lobe tumors
Metabolic alkalosis
Temporal lobe epilepsy (Correct answer)

Correct answer: Temporal lobe epilepsy

TIRDA, while not epileptiform itself, is strongly associated with temporal lobe epilepsy and should prompt clinical correlation for seizure disorder.

Question 68: Which ICU patient population has the highest risk of nonconvulsive seizures, justifying prompt cEEG monitoring?

Patients with uncomplicated metabolic encephalopathy
Patients with acute convulsive status epilepticus treated with benzodiazepines (Correct answer)
Postoperative patients after elective spine surgery
Patients with stable chronic epilepsy

Correct answer: Patients with acute convulsive status epilepticus treated with benzodiazepines

After convulsive status epilepticus is terminated with benzodiazepines, up to 48% of patients continue to have nonconvulsive seizures detectable only by EEG.

Question 69: Alpha intrusion into NREM sleep (alpha-delta sleep) is associated with:

Non-restorative sleep and fibromyalgia (Correct answer)
Enhanced slow-wave sleep recovery
Increased REM density
Normal aging in patients over 60

Correct answer: Non-restorative sleep and fibromyalgia

Alpha-delta sleep, where alpha activity intrudes into slow-wave sleep, is linked to non-restorative sleep and is commonly described in fibromyalgia patients.

Question 70: Which evoked potential modality is most useful for monitoring spinal cord function during scoliosis correction surgery?

Somatosensory evoked potentials (Correct answer)
P300 event-related potentials
Visual evoked potentials
Brainstem auditory evoked potentials

Correct answer: Somatosensory evoked potentials

SSEPs monitor the dorsal column sensory pathways of the spinal cord, making them the primary tool for detecting cord compromise during spinal instrumentation.

Question 71: In a comatose patient following an anoxic brain injury, the EEG shows periods of high-voltage, mixed-frequency activity lasting 1-3 seconds, which are separated by periods of profound voltage attenuation (<10 µV) lasting 4-8 seconds. This pattern is known as:

Burst-suppression (Correct answer)
Hypsarrhythmia
Alpha coma
Slow spike-and-wave

Correct answer: Burst-suppression

The described pattern of alternating high-amplitude 'bursts' with periods of near-isoelectric 'suppression' is the definition of a burst-suppression pattern. It indicates profound cerebral dysfunction and is often seen in conditions like severe anoxia, deep anesthesia, or certain encephalopathies.

Question 72: In pediatric EEG, the posterior dominant rhythm (PDR) reaches its adult frequency of approximately 10 Hz by what age?

3 years
15 years
1 year
8–10 years (Correct answer)

Correct answer: 8–10 years

The posterior dominant rhythm gradually increases from about 3.5 Hz at 3 months to the adult alpha frequency of ~10 Hz by 8–10 years of age.

Question 73: Which epileptiform pattern consists of high-amplitude, chaotic, multifocal spikes and slow waves seen in infantile spasms?

Hypsarrhythmia (Correct answer)
Focal cortical dysplasia pattern
Electrical status epilepticus in sleep
Generalized polyspike-and-wave

Correct answer: Hypsarrhythmia

Hypsarrhythmia is the classic interictal EEG pattern of infantile spasms (West syndrome), characterized by high-amplitude disorganized slow waves with multifocal spikes.

Question 74: What is the normal frequency range of the posterior dominant rhythm (alpha rhythm) in a healthy awake adult?

21-30 Hz
14-20 Hz
8-13 Hz (Correct answer)
4-7 Hz

Correct answer: 8-13 Hz

The normal adult posterior dominant rhythm falls within the alpha frequency band of 8-13 Hz, typically with a mean frequency around 10 Hz. It is best seen over the occipital regions with eyes closed.

Question 75: Which pattern is characterized by generalized, bisynchronous rhythmic delta activity seen predominantly over posterior head regions and is a non-epileptiform finding?

PLED
OIRDA (Occipital Intermittent Rhythmic Delta Activity) (Correct answer)
GRDA
Hypsarrhythmia

Correct answer: OIRDA (Occipital Intermittent Rhythmic Delta Activity)

OIRDA consists of occipitally predominant rhythmic delta bursts, is associated with encephalopathy or posterior fossa lesions, and is not inherently epileptiform.

Question 76: Which behavioral state in neonates is associated with continuous low-to-moderate amplitude mixed-frequency EEG activity?

Active sleep (REM) (Correct answer)
Deep quiet sleep
Quiet sleep (NREM)
Awake crying state

Correct answer: Active sleep (REM)

Active (REM) sleep in neonates is characterized by continuous, relatively low-amplitude mixed-frequency activity similar to wakefulness.

Question 77: During the transition from wakefulness to drowsiness, the expected EEG changes include:

Attenuation of the posterior dominant rhythm with appearance of diffuse theta activity and slow rolling eye movements (Correct answer)
Increase in beta activity throughout
Increase in alpha amplitude and frequency
Appearance of generalized sharp waves

Correct answer: Attenuation of the posterior dominant rhythm with appearance of diffuse theta activity and slow rolling eye movements

The wake-to-drowsiness transition is marked by progressive attenuation of the posterior dominant rhythm (alpha dropout), replacement by diffuse low-amplitude theta activity, slow lateral eye movements, and eventually vertex sharp waves marking Stage N1.

Question 78: Amplitude-integrated EEG (aEEG) is most commonly used in which clinical setting?

Neonatal intensive care units for continuous cerebral monitoring of high-risk newborns (Correct answer)
Adult outpatient epilepsy monitoring units for seizure localization
Intraoperative monitoring during spinal cord surgery
Outpatient ambulatory studies in adults with suspected absence epilepsy

Correct answer: Neonatal intensive care units for continuous cerebral monitoring of high-risk newborns

aEEG was developed specifically for continuous cerebral function monitoring in neonates. It compresses and amplitude-integrates the EEG into a single trend channel, making it practical for bedside nurses and neonatologists to monitor brain activity, detect seizures, and assess background continuity in premature and term newborns with hypoxic-ischemic encephalopathy.

Question 79: Focal polymorphic delta activity (PDA) over the right temporal region in an awake adult most strongly suggests:

Medication effect from benzodiazepines
Normal drowsiness
A structural lesion in the right temporal area (Correct answer)
Generalized metabolic encephalopathy

Correct answer: A structural lesion in the right temporal area

Focal polymorphic delta activity is a highly localizing finding indicating structural pathology (tumor, stroke, abscess) disrupting normal cortical-subcortical connections in the region where it appears.

Question 80: Wave with a single deviation from the baseline, either up or down.

Transient
Monophasic (Correct answer)
Polyphasic
Paroxysmal

Correct answer: Monophasic

Monophasic waves have only one deflection from the baseline, either up or down. This indicates that there is only one phase or motion direction for the wave. Unlike polyphasic waves, it does not exhibit many phases or deflections. Paroxysmal describes abrupt, intense episodes, transient describes something that is fleeting or short-lived, and epileptiform describes waveforms that resemble those observed in epilepsy.

Question 81: What are the typical high-pass and low-pass filter settings used when recording brainstem auditory evoked potentials (BAEPs)?

1–100 Hz
0.1–30 Hz
1000–10000 Hz
100–3000 Hz (Correct answer)

Correct answer: 100–3000 Hz

BAEP waveforms contain frequencies predominantly in the 100–3000 Hz range; these bandpass settings preserve the fast transient potentials while rejecting low-frequency muscle artifact and EEG.

Question 82: During a recording, an epileptiform discharge characterized by a sharp wave followed by a slow wave is observed. The slow wave component is physiologically understood to represent:

A secondary burst of excitatory postsynaptic potentials (EPSPs)
Artifact from patient movement following the sharp wave
A prolonged afterhyperpolarization and inhibitory postsynaptic potentials (IPSPs) (Correct answer)
The summation of multiple action potentials

Correct answer: A prolonged afterhyperpolarization and inhibitory postsynaptic potentials (IPSPs)

The slow wave following an interictal spike or sharp wave represents a period of profound inhibition. This is caused by the activation of inhibitory interneurons, leading to inhibitory postsynaptic potentials (IPSPs) and a prolonged afterhyperpolarization in the surrounding neuronal population, which temporarily suppresses excitability.

Question 83: An electrode pop artifact on EEG is characterized by:

Abrupt, high-amplitude deflection confined to a single channel (Correct answer)
Bilateral synchronous sharp waves
Rhythmic activity at 14 Hz
Gradual onset sinusoidal waveform

Correct answer: Abrupt, high-amplitude deflection confined to a single channel

Electrode pop appears as a sudden, high-amplitude spike-like deflection isolated to one channel, caused by abrupt impedance change at a single electrode due to drying gel, poor contact, or mechanical disturbance.

Question 84: Which of the following EEG findings is most characteristic of a patient performing lateral eye movements to the right?

A slow positive deflection at F8 and a slow negative deflection at F7. (Correct answer)
A sharp positive deflection at F7 and a sharp negative deflection at F8.
High-amplitude, synchronous slow waves in all frontal channels.
Rhythmic 8 Hz sinusoidal waves in the Fp1 and Fp2 channels.

Correct answer: A slow positive deflection at F8 and a slow negative deflection at F7.

Due to the corneoretinal potential, the cornea of the eye is positively charged relative to the retina. When the eyes move to the right, the positive cornea moves closer to the F8 electrode, creating a positive deflection, and further from the F7 electrode, creating a negative deflection. This results in a characteristic out-of-phase potential between the two electrodes.

Question 85: What is the standard low-frequency filter (LFF) setting used in routine clinical EEG?

0.1 Hz
1 Hz (Correct answer)
10 Hz
5 Hz

Correct answer: 1 Hz

A low-frequency filter of 1 Hz (high-pass filter) is the standard setting for routine EEG to reduce slow baseline drift.

Question 86: Generalized paroxysmal fast activity (GPFA) during slow-wave sleep is the characteristic ictal correlate of which seizure type in Lennox-Gastaut syndrome?

Absence seizures
Atonic seizures
Tonic seizures (Correct answer)
Myoclonic seizures

Correct answer: Tonic seizures

Tonic seizures in Lennox-Gastaut syndrome are associated with generalized paroxysmal fast activity (GPFA, 10–25 Hz) predominantly during NREM sleep.

Question 87: Which of the following statements is true regarding beta activity in a normal adult EEG?

It is often enhanced fronto-centrally by drowsiness or certain medications like benzodiazepines. (Correct answer)
It is typically highest in amplitude in the occipital regions.
It is always considered an abnormal finding in an awake adult.
It is defined as activity in the 4-7 Hz frequency range.

Correct answer: It is often enhanced fronto-centrally by drowsiness or certain medications like benzodiazepines.

Beta activity (>13 Hz) is a normal rhythm, typically low in amplitude and most evident in the frontal and central regions. Its amplitude can be enhanced by a state of drowsiness or by the use of sedative-hypnotic drugs, such as benzodiazepines and barbiturates.

Question 88: A technologist notices intermittent square-wave transients isolated to a single electrode that disappear when the electrode impedance is rechecked and re-gelled. This is most consistent with:

Muscle artifact
Sweat artifact
EKG artifact
Electrode pop (Correct answer)

Correct answer: Electrode pop

Electrode pops are caused by intermittent loss of contact or impedance instability at a single electrode and typically resolve with re-application.

Question 89: Analog-to-digital conversion in digital EEG requires an anti-aliasing filter because:

It increases the number of recording channels
It improves electrode impedance
It reduces the file size of the digital recording
Without it, frequencies above the Nyquist frequency would be misrepresented as lower frequencies in the digital record (Correct answer)

Correct answer: Without it, frequencies above the Nyquist frequency would be misrepresented as lower frequencies in the digital record

The anti-aliasing filter (a low-pass filter set below the Nyquist frequency) prevents aliasing — the phenomenon where frequencies above half the sampling rate are incorrectly represented as lower frequencies in the digital signal.

Question 90: Sleep spindles are generated primarily by thalamocortical circuits involving which thalamic nucleus?

Pulvinar
Reticular nucleus of the thalamus (Correct answer)
Lateral geniculate nucleus
Centromedian nucleus

Correct answer: Reticular nucleus of the thalamus

The thalamic reticular nucleus acts as a pacemaker for sleep spindles through rhythmic inhibitory postsynaptic potentials to relay nuclei.

Question 91: Which of the following statements accurately describes the fundamental principle of a bipolar montage?

It requires a non-cephalic reference to avoid contamination from brain activity.
It is designed to be less sensitive to localized abnormalities compared to referential montages.
It measures the voltage difference between adjacent electrodes in a chain. (Correct answer)
It measures the voltage difference between each electrode and a mathematically derived average of all electrodes.

Correct answer: It measures the voltage difference between adjacent electrodes in a chain.

The core principle of a bipolar montage is the measurement of the potential difference between pairs of adjacent electrodes. These pairs are linked together to form chains, which can run anterior-posterior (longitudinal) or left-right (transverse). This method is effective for localizing focal events by identifying phase reversals.

Question 92: What is the recommended distance between the photic stimulator and the patient's eyes during intermittent photic stimulation?

30 cm (Correct answer)
5 cm
200 cm
100 cm

Correct answer: 30 cm

The standard distance for the photic stimulator is approximately 30 cm from the patient's closed eyes, providing adequate light intensity for activation while maintaining patient comfort and safety.

Question 93: Excessive beta activity (above 25 µV) generalized across the recording is most commonly associated with:

Posterior fossa tumor
Sedative or anxiolytic medication use such as benzodiazepines (Correct answer)
Normal hyperventilation response
Temporal lobe epilepsy

Correct answer: Sedative or anxiolytic medication use such as benzodiazepines

Generalized excessive beta activity is most commonly a pharmacological effect of benzodiazepines, barbiturates, or other sedative-hypnotic medications, which enhance GABAergic inhibition and increase fast cortical activity.

Question 94: K-complexes are characterized by which of the following features?

Bilateral occipital alpha bursts during drowsiness
Low-amplitude fast activity in temporal regions during REM sleep
A biphasic wave with initial sharp negative component followed by a positive slow wave, maximal at the vertex during N2 sleep (Correct answer)
Continuous monomorphic theta activity in frontal regions

Correct answer: A biphasic wave with initial sharp negative component followed by a positive slow wave, maximal at the vertex during N2 sleep

K-complexes are large biphasic waves with an initial sharp negative deflection followed by a slower positive component, maximal at Fz/Cz, occurring spontaneously or in response to stimuli during Stage N2 sleep.

Question 95: Which waveform is considered a normal variant and is characteristically seen at the vertex during stage N1 sleep?

Sleep spindle
Vertex sharp wave (Correct answer)
K-complex
Lambda wave

Correct answer: Vertex sharp wave

Vertex sharp waves (V-waves) are normal, high-amplitude transients maximal at Cz that appear during drowsiness and stage N1 sleep.

Question 96: Stimulus-induced rhythmic, periodic, or ictal-looking discharges (SIRPIDs) are important to recognize because they:

Indicate the patient is about to have a tonic-clonic seizure
Are only seen in outpatient EEG recordings
Always require immediate anticonvulsant treatment
May represent a cortical irritability pattern that mimics seizures but occurs in response to stimulation in critically ill patients (Correct answer)

Correct answer: May represent a cortical irritability pattern that mimics seizures but occurs in response to stimulation in critically ill patients

SIRPIDs are rhythmic or periodic patterns triggered by alerting stimuli (suctioning, turning, examination) in critically ill patients. They may mimic seizures but are stimulus-provoked and their treatment significance remains debated.

Question 97: Periodic discharges on the ictal-interictal continuum are challenging because:

They can only be seen on intracranial EEG
They are always benign normal variants
They exist between clearly interictal and clearly ictal patterns, with uncertain clinical significance regarding ongoing brain injury (Correct answer)
They always require immediate anticonvulsant loading

Correct answer: They exist between clearly interictal and clearly ictal patterns, with uncertain clinical significance regarding ongoing brain injury

Patterns on the ictal-interictal continuum (periodic discharges, rhythmic delta) share features of both interictal and ictal patterns, creating diagnostic uncertainty about whether they represent ongoing seizure activity causing brain injury or a non-ictal irritative pattern.

Question 98: Breach rhythm is a normal consequence of a skull defect that appears as:

Generalized voltage attenuation across all electrodes
Higher-amplitude, sharper-appearing activity over the skull defect due to reduced signal attenuation by bone (Correct answer)
Focal delta slowing at the site of the defect
Loss of all electrical activity over the affected area

Correct answer: Higher-amplitude, sharper-appearing activity over the skull defect due to reduced signal attenuation by bone

Breach rhythm occurs when a skull defect (craniotomy, fracture) removes the attenuating and filtering effect of bone, allowing higher-amplitude, faster, sharper-appearing activity to be recorded from the overlying electrode.

Question 99: During an EEG recording, a technologist notices significant 60 Hz artifact across all channels. Which of the following instrument settings should be adjusted to specifically target and reduce this type of interference?

Notch Filter (Correct answer)
Low-Frequency Filter
High-Frequency Filter
Sensitivity

Correct answer: Notch Filter

The Notch Filter is specifically designed to attenuate a very narrow band of frequencies. In North America, this is set to 60 Hz to eliminate interference from the AC electrical power lines. It should be used judiciously as it can sometimes distort clinically relevant activity near that frequency.

Question 100: What does a prolonged I–III interpeak interval in BAEPs indicate?

Cortical auditory processing disorder
Cochlear pathology
Midbrain compression
Pontine lesion between cochlear nucleus and superior olive (Correct answer)

Correct answer: Pontine lesion between cochlear nucleus and superior olive

The I–III interpeak interval reflects conduction time through the lower brainstem (caudal pons), so prolongation indicates a lesion in that segment.

Question 101: The blood-brain barrier's role in EEG is primarily related to:

Producing artifact from cerebral blood flow
Filtering EEG signals before they reach the scalp
Maintaining the ionic environment necessary for proper neuronal electrical activity (Correct answer)
Directly generating electrical potentials recorded on the scalp

Correct answer: Maintaining the ionic environment necessary for proper neuronal electrical activity

The blood-brain barrier maintains the precise ionic composition of the extracellular fluid (particularly Na+, K+, Ca2+, and Cl- concentrations) essential for proper neuronal membrane potentials and synaptic transmission that generate EEG signals.

Question 102: Which of the following describes the typical, normal response to hyperventilation in a healthy 8-year-old child's EEG?

Attenuation of the posterior dominant rhythm with no other changes.
A buildup of generalized, rhythmic, high-amplitude delta and theta slowing. (Correct answer)
The appearance of generalized 3 Hz spike-and-wave discharges.
Development of focal sharp waves over the temporal regions.

Correct answer: A buildup of generalized, rhythmic, high-amplitude delta and theta slowing.

A normal response to HV, especially prominent in children and adolescents, is the development of generalized, often high-amplitude, rhythmic slowing in the delta and theta frequency ranges. This is known as a "buildup" response and should resolve shortly after HV is discontinued. Generalized spike-and-wave or focal sharps would be abnormal findings.

Question 103: Which normal EEG feature is defined as a 12–14 Hz waxing-and-waning burst lasting 0.5–3 seconds, maximal over central-parietal regions?

K-complex
Positive occipital sharp transient (POST)
Vertex sharp wave
Sleep spindle (Correct answer)

Correct answer: Sleep spindle

Sleep spindles are 12–14 Hz (sigma band) bursts with a characteristic spindle shape appearing in stage N2 sleep.

Question 104: When a square wave calibration signal shows 'ringing' or oscillations after the rising edge, this most likely indicates:

The electrode impedance is too low
The high-frequency filter cutoff is set too high, allowing high-frequency resonance (Correct answer)
The amplifier gain is set too high
The low-frequency filter cutoff is set too high

Correct answer: The high-frequency filter cutoff is set too high, allowing high-frequency resonance

Ringing after the rising edge of a square wave indicates the high-frequency filter cutoff is set too high, allowing the amplifier to pass and amplify resonant high-frequency components at the step transition.

Question 105: Burst suppression on EEG in a critically ill patient is characterized by:

Repetitive spike-wave complexes at 3 Hz
Beta-predominant activity with rare slow waves
Continuous high-amplitude delta slowing
Alternating bursts of high-amplitude mixed activity and periods of near-flat EEG (Correct answer)

Correct answer: Alternating bursts of high-amplitude mixed activity and periods of near-flat EEG

Burst suppression consists of bursts of mixed-frequency, often high-amplitude activity alternating with periods of electrocerebral suppression (<10 µV), indicating severe cerebral dysfunction.

Question 106: Which EEG feature helps distinguish benign childhood epilepsy with centrotemporal spikes (BECTS/BCECTS) from other focal epilepsies?

High-amplitude centrotemporal spikes that increase during NREM sleep and have a characteristic horizontal dipole (Correct answer)
Multifocal independent spikes
Suppression of alpha rhythm over the affected hemisphere
Spikes that persist during all sleep stages

Correct answer: High-amplitude centrotemporal spikes that increase during NREM sleep and have a characteristic horizontal dipole

BECTS is characterized by high-amplitude centrotemporal sharp waves with a horizontal dipole that markedly activate (increase in frequency) during NREM sleep.

Question 107: What is the minimum percentage of an epoch that must consist of delta waves for that epoch to be scored as stage N3 sleep?

10%
50%
75%
20% (Correct answer)

Correct answer: 20%

By AASM scoring rules, stage N3 requires that delta waves (0.5–2 Hz, >75 µV) occupy at least 20% of a 30-second epoch.

Question 108: Temporal intermittent rhythmic delta activity (TIRDA) is significant because it:

Is caused by electrode artifact at temporal sites
Has a strong association with temporal lobe epilepsy even in the absence of spikes (Correct answer)
Is always a normal variant in elderly patients
Indicates brainstem dysfunction

Correct answer: Has a strong association with temporal lobe epilepsy even in the absence of spikes

TIRDA (temporal intermittent rhythmic delta activity) has a high correlation with temporal lobe epilepsy and is considered an epileptiform-equivalent pattern, even when no spikes or sharp waves are present.

Question 109: Which statement about electrode impedance is correct for clinical EEG?

Impedance only affects artifact, not signal amplitude
Higher impedance improves signal quality
Impedance should be below 5 kΩ for optimal recording (Correct answer)
Impedance above 20 kΩ is acceptable

Correct answer: Impedance should be below 5 kΩ for optimal recording

Electrode impedance should be below 5 kΩ (ideally 1-5 kΩ) to ensure adequate signal quality and minimize noise artifacts.

Question 110: An alert and oriented adult patient provides consent for an EEG but adamantly refuses the hyperventilation (HV) activation procedure due to a history of panic attacks. Which of the following is the most appropriate course of action for the technologist?

Respect the patient's refusal, document it on the record, and proceed with the remainder of the EEG. (Correct answer)
Insist that the patient attempt HV, as it is a required part of the standard procedure.
Ask a family member to convince the patient to perform the procedure.
Cancel the entire EEG study because it will be incomplete without the activation.

Correct answer: Respect the patient's refusal, document it on the record, and proceed with the remainder of the EEG.

Competent adult patients have the right to refuse any part of a medical procedure. The technologist must respect the patient's autonomy. The proper action is to document the refusal clearly on the technologist's report and continue with the other parts of the study, such as photic stimulation and obtaining a sleep recording.

Question 111: A patient on high-dose phenobarbital for status epilepticus shows a burst-suppression pattern on EEG. Which feature is most characteristic of drug-induced burst suppression compared to anoxic burst suppression?

Suppression periods are always longer than 10 seconds
Burst suppression is dose-dependent and reverses as the drug is metabolized (Correct answer)
Delta activity is absent during burst periods
Bursts are consistently asymmetric between hemispheres

Correct answer: Burst suppression is dose-dependent and reverses as the drug is metabolized

Drug-induced burst suppression (from barbiturates, propofol, or benzodiazepines) is dose-dependent and will improve as serum drug levels fall. Anoxic burst suppression following cardiac arrest is not dose-dependent and carries a far worse prognosis. This distinction is clinically critical for EEG interpretation in the ICU.

Question 112: Hypsarrhythmia on EEG is the interictal hallmark of which epilepsy syndrome?

Landau-Kleffner syndrome
West syndrome (Correct answer)
Lennox-Gastaut syndrome
Ohtahara syndrome

Correct answer: West syndrome

Hypsarrhythmia — chaotic high-amplitude activity with multifocal spikes — is the characteristic interictal EEG pattern of West syndrome (infantile spasms).

Question 113: Dynamic range in digital EEG refers to:

The number of channels that can record simultaneously
The frequency range the system can display
The maximum recording duration
The range of signal amplitudes the system can accurately digitize, from the smallest to the largest signal without distortion (Correct answer)

Correct answer: The range of signal amplitudes the system can accurately digitize, from the smallest to the largest signal without distortion

Dynamic range is the ratio between the largest and smallest signal amplitudes the ADC can accurately represent, determined by the bit resolution of the analog-to-digital converter.

Question 114: What guidance should patients receive about bathing and water exposure during an ambulatory EEG recording?

Normal bathing and swimming are permitted
Brief hot showers are encouraged to improve electrode contact
Water exposure has no effect on ambulatory EEG recordings
Patients should avoid submerging the recording equipment in water and typically should not shower or bathe to maintain electrode integrity (Correct answer)

Correct answer: Patients should avoid submerging the recording equipment in water and typically should not shower or bathe to maintain electrode integrity

Patients should avoid bathing, showering, and swimming during ambulatory EEG as water can degrade electrode adhesion, increase impedances, damage the recording equipment, and compromise data quality.

Question 115: Which of the following flash frequencies used in intermittent photic stimulation (IPS) is most likely to elicit a photoparoxysmal response in photosensitive individuals?

1–2 Hz
50 Hz
15–20 Hz (Correct answer)
3–5 Hz

Correct answer: 15–20 Hz

Frequencies between approximately 15–20 Hz are the most common range for provoking photoparoxysmal responses in photosensitive patients.

Question 116: Which of the following best describes the function of a referential (monopolar) montage in EEG recording?

Each channel records the difference between two adjacent active electrodes
Each channel records the difference between one active electrode and a common reference (Correct answer)
Channels are arranged to show voltage gradients across the scalp
All electrodes are linked together to form a single average

Correct answer: Each channel records the difference between one active electrode and a common reference

In a referential montage, each channel compares one active scalp electrode to a single common reference electrode (such as Cz, ipsilateral ear, or average reference).

Question 117: In normal neonatal EEGs, which activity pattern is considered developmentally appropriate but would be abnormal in a healthy adult?

Continuous alpha rhythm
Trace alternant (burst-suppression-like) pattern during quiet sleep (Correct answer)
Prominent lambda waves
Persistent 14 Hz spindles

Correct answer: Trace alternant (burst-suppression-like) pattern during quiet sleep

Trace alternant, characterized by alternating bursts and interburst intervals during quiet sleep, is a normal pattern in full-term neonates up to about 44 weeks conceptional age.

Question 118: Which scenario represents an appropriate use of physical restraint during a pediatric EEG?

Using a papoose board with parental consent and physician order when medically necessary and less restrictive methods have failed (Correct answer)
Using restraints whenever a child cries during electrode application
Restraining a cooperative child simply to shorten setup time
Applying wrist restraints routinely to prevent electrode displacement in all children under age 5

Correct answer: Using a papoose board with parental consent and physician order when medically necessary and less restrictive methods have failed

Restraint requires a physician order, parental consent, documented failure of alternatives, and must be the least restrictive option necessary.

Question 119: What impedance level is considered acceptable for EEG electrodes before starting a recording?

Below 50,000 ohms
Below 100 kΩ
Below 5,000 ohms (5 kΩ) (Correct answer)
Below 500 ohms

Correct answer: Below 5,000 ohms (5 kΩ)

Electrode impedances should be below 5 kΩ (and ideally matched between electrodes) to ensure low-artifact, high-quality recordings.

Question 120: Impedance checks during ambulatory EEG should be performed:

Never, as they interrupt the recording
Only if artifacts are visible on the recording
At hookup and at each follow-up visit or when the recording device is checked (Correct answer)
Only at the initial hookup

Correct answer: At hookup and at each follow-up visit or when the recording device is checked

Impedances should be checked at initial hookup and at scheduled follow-up visits (typically daily for multi-day recordings) to identify and correct electrode degradation before it compromises recording quality.

Question 121: Which of the following would prompt the technologist to STOP hyperventilation immediately?

The patient develops a tonic-clonic seizure (Correct answer)
The patient exhibits build-up of generalized slow waves
The patient reports mild tingling in the fingertips
The patient appears slightly drowsy

Correct answer: The patient develops a tonic-clonic seizure

A tonic-clonic seizure requires immediate cessation of HV and initiation of seizure safety protocols and notification of supervising physician.

Question 122: What are the three main types of evoked potentials commonly recorded in a clinical neurophysiology laboratory?

Cortical, Subcortical, and Peripheral
Motor, Sensory, and Cognitive
Visual, Auditory, and Somatosensory (Correct answer)
Pattern, Flash, and Click

Correct answer: Visual, Auditory, and Somatosensory

The three main clinical evoked potentials are Visual (VEP), Auditory (BAEP/ABR), and Somatosensory (SSEP), each assessing a different sensory pathway.

Question 123: According to the American Clinical Neurophysiology Society (ACNS) guidelines, interelectrode impedances should be within what range for a standard EEG recording?

Above 50,000 Ohms (50 kOhms)
Below 100 Ohms
Between 100 Ohms and 10,000 Ohms (10 kOhms) (Correct answer)
Exactly 5,000 Ohms (5 kOhms)

Correct answer: Between 100 Ohms and 10,000 Ohms (10 kOhms)

ACNS guidelines state that interelectrode impedances should be under 10,000 Ohms (10 kOhms) but over 100 Ohms. Impedances that are too high can lead to increased noise and artifact, while impedances below 100 Ohms may suggest a salt bridge or short circuit between electrodes. While values under 5 kOhms are often recommended, the acceptable range is up to 10 kOhms.

Question 124: A common challenge unique to ambulatory EEG compared to in-lab recording is:

Requirement for general anesthesia
Lack of patient diary correlation
Increased susceptibility to movement and environmental artifacts (Correct answer)
Inability to record delta frequencies

Correct answer: Increased susceptibility to movement and environmental artifacts

Ambulatory recordings are highly susceptible to movement artifact, cable sway, and environmental electrical interference because the patient moves freely in daily life.

Question 125: Which non-epileptiform EEG pattern is characterized by high-voltage, chaotic slow and sharp waves without organized background activity, classically seen in infantile spasms?

Triphasic waves
GRDA
Hypsarrhythmia (Correct answer)
Burst suppression

Correct answer: Hypsarrhythmia

Hypsarrhythmia is the interictal EEG hallmark of West syndrome (infantile spasms), featuring high-amplitude disorganized slow activity with multifocal spikes.

Question 126: The electrode labeled 'Fz' in the 10-20 system is located at:

The midline frontal position (Correct answer)
The left frontotemporal junction
The right frontopolar region
The left frontal region

Correct answer: The midline frontal position

The 'z' designation indicates a midline position. Fz (frontal zero) is the midline frontal electrode positioned at 30% of the nasion-to-inion distance from the nasion.

Question 127: Which principle of biomedical ethics requires the EEG technologist to provide adequate information before obtaining consent for photic stimulation?

Non-maleficence
Justice
Beneficence
Autonomy (Correct answer)

Correct answer: Autonomy

Autonomy requires that patients receive sufficient information to make an informed decision about procedures such as photic stimulation.

Question 128: According to the American Clinical Neurophysiology Society (ACNS) guidelines, an epileptiform discharge is classified as a 'sharp wave' based on which of the following duration ranges?

20-70 milliseconds
> 200 milliseconds
70-200 milliseconds (Correct answer)
< 20 milliseconds

Correct answer: 70-200 milliseconds

A sharp wave is defined as a transient with a pointed peak and a duration of 70 to 200 milliseconds. Discharges with a duration of less than 70 ms are classified as spikes, and waves lasting longer than 200 ms are considered slow waves.

Question 129: Vertex sharp waves (V waves) during drowsiness are maximally recorded at which electrode position?

Cz (Correct answer)
O1 and O2
T3 and T4
Fp1 and Fp2

Correct answer: Cz

Vertex sharp waves are high-amplitude, surface-negative sharp transients maximal at the vertex (Cz electrode) that appear during drowsiness and Stage N1 sleep as a normal finding.

Question 130: What is the typical frequency range of theta activity in EEG?

13-30 Hz
8-13 Hz
0.5-4 Hz
4-8 Hz (Correct answer)

Correct answer: 4-8 Hz

Theta activity ranges from 4-8 Hz. In adults, mild theta activity is normal during drowsiness but persistent theta during wakefulness suggests encephalopathy. In children, more theta activity is normal.

Question 131: Rhythmic delta activity (RDA) in the ICU that shows an evolution in frequency or distribution should prompt the clinician to consider:

Medication effect from benzodiazepines
Normal sleep architecture
Calibration error
Possible seizure activity requiring further evaluation (Correct answer)

Correct answer: Possible seizure activity requiring further evaluation

Evolving RDA may represent ictal activity on the ictal-interictal continuum, and evolution is a key feature that raises concern for seizures rather than a static encephalopathic pattern.

Question 132: Which EEG pattern is characterized by a spike followed by a slow wave complex occurring at approximately 3 Hz?

Hypsarrhythmia
Burst suppression
Generalized 3 Hz spike-and-wave (Correct answer)
Periodic lateralized epileptiform discharges

Correct answer: Generalized 3 Hz spike-and-wave

The classic 3 Hz spike-and-wave pattern is the hallmark of childhood absence epilepsy, appearing as generalized, synchronous, bilateral discharges.

Question 133: A patient's EEG recording shows a focal discharge. To best define the point of maximum electronegativity and pinpoint the origin of the activity, which type of montage is most effective?

Laplacian montage
Bipolar 'double banana' montage
Transverse bipolar montage
Referential montage (Correct answer)

Correct answer: Referential montage

Referential montages compare the voltage of each scalp electrode to a single, common reference point. This configuration is particularly useful for determining the electrode with the highest amplitude abnormality, which helps to clarify the point of maximal electronegativity when it might be unclear on a bipolar view.

Question 134: Mismatch negativity (MMN) is unique among auditory evoked potentials because it:

Requires the patient to actively attend to sounds
Requires bilateral hearing for generation
Only occurs with painful stimulation
Can be recorded during sleep or in unresponsive patients (Correct answer)

Correct answer: Can be recorded during sleep or in unresponsive patients

MMN is a pre-attentive, automatic response to auditory change that can be recorded without voluntary attention, making it useful for assessing auditory discrimination in comatose patients.

Question 135: Modified neonatal montages differ from standard adult montages primarily by:

Using only midline electrodes
Recording at higher paper speeds exclusively
Using the same 10-20 system without any modifications
Using fewer electrodes with adjusted placement for the smaller head size and including polygraphic channels for behavioral state assessment (Correct answer)

Correct answer: Using fewer electrodes with adjusted placement for the smaller head size and including polygraphic channels for behavioral state assessment

Neonatal montages use fewer electrodes (typically 9-11 EEG channels) adapted for the small head, modified placement to cover areas of clinical importance, and include polygraphic channels (EMG, EOG, ECG, respiration) essential for state assessment.

Question 136: Which neurotransmitter released by basal forebrain neurons desynchronizes the EEG and promotes wakefulness by depolarizing cortical neurons?

Glycine
GABA
Acetylcholine (Correct answer)
Serotonin

Correct answer: Acetylcholine

Basal forebrain cholinergic neurons release acetylcholine onto cortical neurons, causing depolarization and EEG desynchronization characteristic of wakefulness and REM sleep.

Question 137: The posterior dominant rhythm (PDR) in a healthy 8-year-old child is expected to have a frequency of approximately:

9 Hz (Correct answer)
6-7 Hz
4-5 Hz
11-12 Hz

Correct answer: 9 Hz

The frequency of the posterior dominant rhythm matures with age. It starts around 3-4 Hz in infants, reaches 8 Hz by about age 3, and typically achieves a frequency of 9 Hz by age 8. It stabilizes in the adult alpha range of 8-13 Hz in the early teen years.

Question 138: An EEG recording from a 55-year-old patient in a drowsy state shows bilateral, synchronous, rhythmic 5-7 Hz sharply contoured waves over the parietal and posterior temporal regions. The pattern has an abrupt onset and offset, lasts for approximately 45 seconds, and does not evolve in frequency or morphology. The patient remains unresponsive to auditory stimuli during the event. Which of the following non-epileptiform patterns is most likely being observed?

Subclinical Rhythmic Electrographic Discharge of Adults (SREDA) (Correct answer)
Wicket Spikes
14 & 6 Hz Positive Spikes
Rhythmic Mid-Temporal Theta of Drowsiness (RMTD)

Correct answer: Subclinical Rhythmic Electrographic Discharge of Adults (SREDA)

Subclinical Rhythmic Electrographic Discharge of Adults (SREDA) is characterized by bilateral, widespread, rhythmic, and sharply-contoured theta activity with a parietal-posterior temporal maximum. It has an abrupt onset/offset, does not evolve, and occurs without any clinical symptoms, fitting the description perfectly. [14, 25] RMTD is typically mid-temporal and shorter in duration. [2, 8] Wicket spikes are arc-shaped and occur in the temporal regions, often independently. [2, 35] 14 & 6 Hz positive spikes have a different frequency and morphology.

Question 139: A patient's family member requests a copy of the EEG report. Under what condition can the technologist release this information?

The technologist can release it immediately upon request
Only after obtaining proper written authorization consistent with HIPAA regulations (Correct answer)
Reports can never be shared with family members
Only if the family member is a healthcare provider

Correct answer: Only after obtaining proper written authorization consistent with HIPAA regulations

Protected health information including EEG reports can only be released with proper authorization from the patient (or legal representative) in compliance with HIPAA privacy regulations.

Question 140: Gamma oscillations (>30 Hz) in the normal EEG are most associated with which cognitive state?

Deep sleep
High-level cognitive processing and sensory binding (Correct answer)
Drowsiness
REM sleep only

Correct answer: High-level cognitive processing and sensory binding

Gamma oscillations are linked to higher cognitive functions such as attention, working memory, and cross-modal sensory binding.

Question 141: A technologist discovers a previously unknown scalp laceration during electrode application. The appropriate response is to:

Proceed with normal electrode application over the laceration
Apply antiseptic to the wound and proceed with standard placement
Document the finding, avoid placing electrodes directly on the wound, notify the supervising physician, and modify the montage as needed (Correct answer)
Cancel the entire EEG study

Correct answer: Document the finding, avoid placing electrodes directly on the wound, notify the supervising physician, and modify the montage as needed

Discovering a scalp wound requires documentation, avoidance of electrode placement on the wound (infection risk), notification of the clinical team, and appropriate modification of electrode positions while maintaining diagnostic quality.

Question 142: Which EEG frequency band is most prominent during deep NREM sleep (stage N3)?

Theta (4–8 Hz)
Alpha (8–13 Hz)
Beta (13–30 Hz)
Delta (0.5–4 Hz) (Correct answer)

Correct answer: Delta (0.5–4 Hz)

Stage N3 (slow-wave sleep) is defined by high-amplitude delta waves occupying at least 20% of the epoch.

Question 143: A patient undergoing a prolonged EEG develops a stage IV pressure ulcer under a scalp electrode. This outcome best represents a failure in which ethical principle?

Non-maleficence (Correct answer)
Autonomy
Veracity
Justice

Correct answer: Non-maleficence

Non-maleficence — the duty to avoid causing harm — is violated when preventable pressure injuries occur due to inadequate electrode site monitoring.

Question 144: Post-ictal slowing on EEG following a focal seizure is clinically useful because it:

Confirms the seizure was non-epileptic
Indicates the seizure was generalized from onset
Has no clinical significance
Helps lateralize and localize the seizure onset zone by showing regional slowing in the post-ictal period (Correct answer)

Correct answer: Helps lateralize and localize the seizure onset zone by showing regional slowing in the post-ictal period

Post-ictal regional slowing (focal delta or theta) provides lateralizing and localizing information about the seizure onset zone, as the area of maximal slowing typically corresponds to the ictal onset region.

Question 145: What is the appropriate response if a patient refuses to continue with an EEG study midway through recording?

Physically restrain the patient to complete the study
Sedate the patient to complete the recording
Respect the patient's autonomy, safely remove electrodes, and document the incomplete study with the reason for discontinuation (Correct answer)
Ignore the request and continue recording

Correct answer: Respect the patient's autonomy, safely remove electrodes, and document the incomplete study with the reason for discontinuation

Patient autonomy is a fundamental ethical principle. If a competent patient withdraws consent, the technologist must stop the procedure, safely remove electrodes, and document the circumstances of the incomplete study.

Question 146: The thalamocortical relay neurons that synchronize cortical oscillations and contribute to sleep spindles are located in which thalamic nucleus?

Mediodorsal nucleus
Pulvinar
Ventral posterolateral nucleus
Reticular nucleus (Correct answer)

Correct answer: Reticular nucleus

The thalamic reticular nucleus (TRN) GABAergic neurons pace sleep spindles by rhythmically inhibiting thalamocortical relay neurons.

Question 147: During a routine EEG, the technologist notes high-amplitude, repetitive muscle artifact obscuring temporal channels. What is the best initial intervention?

Increase the high-frequency filter to 100 Hz
Ask the patient to relax the jaw and facial muscles (Correct answer)
Increase the sensitivity setting
Switch to a bipolar transverse montage

Correct answer: Ask the patient to relax the jaw and facial muscles

Temporal muscle artifact is best reduced by instructing the patient to relax the jaw and facial muscles to reduce EMG contamination.

Question 148: The 'mu rhythm' seen over the central scalp in a relaxed, awake subject has a frequency overlapping with which other rhythm?

Theta
Gamma
Delta
Alpha (Correct answer)

Correct answer: Alpha

The mu rhythm (8–13 Hz) overlaps the alpha frequency band but is maximal over central (C3/C4) rather than occipital electrodes.

Question 149: A 68-year-old patient with a history of a craniotomy for a meningioma resection presents for a routine EEG. The recording shows a focal area of high-amplitude, sharp, and at times spiky-appearing 6-11 Hz activity directly over the surgical site. This activity is persistent across both awake and drowsy states. Which feature would most strongly differentiate this as Breach Rhythm rather than an epileptiform abnormality?

The absence of an after-going slow wave. (Correct answer)
The high amplitude of the activity compared to the contralateral side.
Its focal and asymmetric nature.
The presence of intermixed beta frequencies.

Correct answer: The absence of an after-going slow wave.

A key distinguishing feature between Breach Rhythm and a true epileptiform discharge is that Breach Rhythm consists of sharp or spiky transients that are not followed by a slow-wave component. [3, 7] While increased amplitude, focal asymmetry, and intermixed faster frequencies are all characteristic of Breach Rhythm, the lack of an associated slow wave is the most definitive feature to rule out an epileptiform spike or sharp wave. [3, 6, 7]

Question 150: An asymmetry in the posterior dominant rhythm amplitude, with the right side consistently 50% lower than the left, suggests:

Normal variant — mild asymmetry is always benign
Left hemisphere hyperexcitability indicating seizure focus
Electrode application error only
Possible structural or functional abnormality of the right hemisphere (Correct answer)

Correct answer: Possible structural or functional abnormality of the right hemisphere

Amplitude asymmetry greater than 50% of the posterior dominant rhythm suggests dysfunction on the lower-amplitude side, potentially from a structural lesion, prior surgery, or cortical atrophy.

Question 151: The insula, buried within the lateral sulcus, is involved in autonomic regulation. Seizures arising from insular cortex most likely affect which EEG electrode chain?

Fz-Cz-Pz
F8-T8-P8-O2
Fp1-F3-C3-P3
F7-T7-P7-O1 (Correct answer)

Correct answer: F7-T7-P7-O1

The insula is accessed via the lateral sulcus and is closest to temporal chain electrodes (F7/T7/P7), making this chain most likely to reflect insular seizure activity.

Question 152: A patient is extremely anxious, resulting in contamination of the frontotemporal channels with persistent, high-frequency, irregular activity. Which of the following is the MOST effective first step a technologist should take to reduce this artifact?

Ask the patient to take a deep breath, relax their jaw, and let their mouth open slightly. (Correct answer)
Re-prep the affected electrodes to lower their impedances.
Increase the low-frequency filter setting to 5 Hz.
Apply the 60 Hz notch filter.

Correct answer: Ask the patient to take a deep breath, relax their jaw, and let their mouth open slightly.

The described artifact is electromyographic (EMG) or muscle artifact, often from tension in the frontalis and temporalis muscles. The most effective initial intervention is to use relaxation techniques to reduce the muscle activity at its source. Asking the patient to relax their jaw is a direct and often successful method for reducing this specific artifact.

Question 153: The time constant of an EEG amplifier determines:

The rate at which a DC-shifted signal decays back to baseline through the low-frequency filter (Correct answer)
The number of channels that can record simultaneously
How quickly the amplifier reaches maximum gain
The maximum amplitude the amplifier can display

Correct answer: The rate at which a DC-shifted signal decays back to baseline through the low-frequency filter

The time constant represents the time it takes for a DC-shifted square wave calibration signal to decay to 37% of its initial value. It is directly related to the low-frequency filter setting.

Question 154: Which cortical layer contains the large pyramidal neurons (Betz cells) that give rise to corticospinal tract fibers?

Layer VI
Layer II
Layer V (Correct answer)
Layer IV

Correct answer: Layer V

Layer V (internal pyramidal layer) contains Betz cells, the large pyramidal neurons projecting to the spinal cord via the corticospinal tract.

Question 155: An ambulatory EEG recording shows a sudden onset of 3 Hz spike-and-wave discharges lasting 12 seconds, coinciding with the patient pressing the event button. This is MOST consistent with:

A psychogenic non-epileptic seizure
A generalized tonic-clonic seizure
A typical absence seizure (Correct answer)
A focal onset impaired awareness seizure

Correct answer: A typical absence seizure

Classic 3 Hz generalized spike-and-wave lasting approximately 10–15 seconds with preserved consciousness is the hallmark of typical absence seizures.

Question 156: When performing a square wave calibration, the 'tilt' or slant on the flat top of the square wave most likely indicates a problem with:

The high-frequency filter setting
Electrode impedance being too high
Amplifier gain being set too high
The low-frequency filter (time constant) setting (Correct answer)

Correct answer: The low-frequency filter (time constant) setting

A tilted or slanted flat top on a square wave calibration signal indicates the low-frequency filter (time constant) is cutting off low-frequency components and distorting the sustained DC portion.

Question 157: In VEP testing, what is the main reason each eye is tested separately with the other eye patched?

To isolate each optic nerve's conduction independently (Correct answer)
To improve signal averaging efficiency
To reduce electrical interference between eyes
To prevent binocular rivalry artifacts

Correct answer: To isolate each optic nerve's conduction independently

Monocular testing isolates the optic nerve pathway anterior to the chiasm, allowing detection of unilateral demyelination or compressive lesions of a single optic nerve.

Question 158: High-frequency, irregular bursts of activity seen maximally over temporal and frontal electrodes during a patient interview are most consistent with:

Cardiac artifact
Electrode noise
Chewing/jaw muscle artifact (Correct answer)
Temporal lobe seizure

Correct answer: Chewing/jaw muscle artifact

Chewing produces high-frequency myogenic artifact maximal over temporal regions due to masseter and temporalis muscle proximity.

Question 159: Occipital intermittent rhythmic delta activity (OIRDA) in a child is most commonly associated with:

Frontal lobe lesion
Medication effect from stimulants
Childhood absence epilepsy or posterior fossa pathology (Correct answer)
Normal aging

Correct answer: Childhood absence epilepsy or posterior fossa pathology

OIRDA in children is most commonly associated with childhood absence epilepsy (where it may be an early finding before typical 3 Hz spike-and-wave develops) or with posterior fossa structural lesions.

Question 160: The K-complex is a normal EEG feature of stage N2 sleep. What is its characteristic morphology?

A monophasic positive deflection at the vertex
A negative sharp wave followed by a positive slow component, often superimposed by a spindle (Correct answer)
A series of positive occipital transients
A high-frequency, low-amplitude spindle

Correct answer: A negative sharp wave followed by a positive slow component, often superimposed by a spindle

A K-complex is a well-delineated negative sharp component followed by a positive slow wave, lasting ≥0.5 s, often with a superimposed sleep spindle.

Question 161: The common mode rejection ratio (CMRR) of an EEG differential amplifier measures its ability to:

Amplify all signals equally across the frequency spectrum
Filter out frequencies above 70 Hz
Maintain constant impedance across all electrodes
Reject signals that are identical at both inputs while amplifying their difference (Correct answer)

Correct answer: Reject signals that are identical at both inputs while amplifying their difference

CMRR quantifies how effectively the differential amplifier rejects common-mode signals (those appearing equally at both inputs, such as 60 Hz noise) while preserving the differential signal (brain activity).

Question 162: What is the physiological mechanism by which hyperventilation activates epileptiform activity?

Hypocapnia causes cerebral vasoconstriction, reducing cerebral blood flow and causing neuronal hyperexcitability (Correct answer)
Hypercapnia causes cerebral vasodilation and increased ICP
Increased oxygen delivery stabilizes neuronal membranes
Respiratory alkalosis suppresses inhibitory interneurons permanently

Correct answer: Hypocapnia causes cerebral vasoconstriction, reducing cerebral blood flow and causing neuronal hyperexcitability

Hyperventilation lowers CO2 (hypocapnia), causing cerebral vasoconstriction, reduced perfusion, and subsequent neuronal hyperexcitability that can provoke epileptiform discharges.

Question 163: Which artifact would most likely appear as a high-amplitude, low-frequency deflection time-locked to the R-wave on ECG?

Chewing artifact
Sweat artifact
Pulse artifact (Correct answer)
Electrode pop

Correct answer: Pulse artifact

Pulse artifact is caused by scalp vessel pulsations under electrodes and appears as slow deflections synchronous with the cardiac cycle.

Question 164: The 'sensitivity' setting on an EEG machine refers to:

The number of channels recorded simultaneously
The speed at which the paper or display advances
The voltage per unit of pen or display deflection (e.g., µV/mm) (Correct answer)
The frequency range captured by the amplifier

Correct answer: The voltage per unit of pen or display deflection (e.g., µV/mm)

Sensitivity in EEG describes how many microvolts of signal produce a given deflection (e.g., 7 µV/mm), controlling the amplitude scale of the recording.

Question 165: For a patient who cannot perform volitional hyperventilation (e.g., young child), an alternative activation method may include:

Bilateral carotid massage
Administering IV benzodiazepines
Applying cold water to the face
Having the child blow on a pinwheel or blow bubbles (Correct answer)

Correct answer: Having the child blow on a pinwheel or blow bubbles

Having young children blow on a pinwheel or blow bubbles is a standard pediatric technique to elicit sustained hyperventilation without requiring volitional cooperation.

Question 166: What EEG finding during photic stimulation represents a normal physiological response?

Frontal intermittent rhythmic delta activity
Photic driving response in occipital regions (Correct answer)
Generalized spike-and-wave complexes
Photoparoxysmal response

Correct answer: Photic driving response in occipital regions

Photic driving is a normal response where occipital rhythms entrain to the flash frequency. It represents normal visual cortex reactivity and should not be confused with pathological photoparoxysmal responses.

Question 167: High-frequency oscillations (HFOs) detected on intracranial EEG in the ICU, specifically ripples (80–250 Hz) and fast ripples (250–500 Hz), are clinically important because they:

Indicate normal synaptic plasticity
Are artifacts from cardiac monitor interference
Mark the epileptogenic zone and may guide surgical resection planning (Correct answer)
Represent normal mu rhythm variants

Correct answer: Mark the epileptogenic zone and may guide surgical resection planning

HFOs, especially fast ripples, are biomarkers of the seizure-generating cortex and are being studied as targets for epilepsy surgery to improve resection outcomes.

Question 168: According to the 10-20 International System nomenclature, which electrode would be located over the left mid-temporal region?

C3
T3 (Correct answer)
T4
Pz

Correct answer: T3

In the 10-20 system, the letter indicates the underlying brain region ('T' for Temporal) and the number indicates the hemisphere. Odd numbers are used for the left hemisphere and even numbers for the right hemisphere. 'z' denotes the midline. Therefore, T3 is the electrode over the left mid-temporal region.

Question 169: Which practice best protects patient confidentiality when transmitting an EEG recording electronically to an interpreting neurologist at another facility?

Send via standard email with the patient's name in the subject line for easy identification
Use a HIPAA-compliant encrypted platform with patient identifiers limited to the minimum necessary (Correct answer)
Attach the file to a shared public cloud folder for easy access
Print the record and fax it to the neurologist's personal fax number

Correct answer: Use a HIPAA-compliant encrypted platform with patient identifiers limited to the minimum necessary

HIPAA requires that electronic protected health information be transmitted only through encrypted, secure channels with minimum necessary disclosure.

Question 170: In a normal adult EEG, what is the expected effect of opening the eyes on the posterior alpha rhythm?

Alpha spreads to frontal regions
Alpha is attenuated or blocked (Correct answer)
Alpha amplitude increases
Alpha frequency increases by 4 Hz

Correct answer: Alpha is attenuated or blocked

Eye opening causes alpha blocking (Berger effect), suppressing posterior alpha due to visual cortex activation.

Question 171: A normal adult EEG background shows a well-organized 10 Hz posterior dominant rhythm. This rhythm is categorized as which frequency band?

Alpha (Correct answer)
Theta
Low beta
Sigma

Correct answer: Alpha

10 Hz falls squarely within the alpha band (8–13 Hz), the normal posterior dominant rhythm of a relaxed, eyes-closed adult.

Question 172: Excitatory postsynaptic potentials (EPSPs) at the apical dendrites of cortical pyramidal neurons produce which electrical field at the scalp?

No measurable potential at the scalp
A surface-negative potential directly over the active cortex (Correct answer)
A surface-positive potential directly over the active cortex
A bipolar field that cancels itself out

Correct answer: A surface-negative potential directly over the active cortex

EPSPs at the apical dendrites create a current sink (negative extracellular field) near the cortical surface, producing a surface-negative potential at the overlying scalp electrode.

Question 173: During intraoperative neurophysiological monitoring, a sudden 50% decrease in SSEP amplitude or a 10% increase in latency should prompt what immediate action?

Increase stimulus rate to improve signal averaging
Alert the surgical team immediately (Correct answer)
Increase the number of averages collected
Switch to a different stimulation site

Correct answer: Alert the surgical team immediately

The '50/10 rule' is the standard alert criterion: a >50% amplitude drop or >10% latency increase warrants immediate notification of the surgeon to allow corrective intervention before permanent injury.

Question 174: A differential amplifier's ability to reject signals that are common to both of its inputs is measured by which of the following specifications?

Sensitivity
Common Mode Rejection Ratio (CMRR) (Correct answer)
Low-Frequency Filter
Input Impedance

Correct answer: Common Mode Rejection Ratio (CMRR)

The Common Mode Rejection Ratio (CMRR) is a critical specification for a differential amplifier. It quantifies how well the amplifier can cancel out identical signals (common mode) present at both input terminals, while amplifying the difference between them. A high CMRR is crucial in EEG to eliminate widespread electrical noise and interference.

Question 175: Which EEG pattern during absence status epilepticus distinguishes it from typical 3-Hz absence discharges?

The spike component disappears leaving pure slow waves
The discharges become fragmented, irregular, and slower (< 2.5 Hz) over time (Correct answer)
Amplitude increases progressively to > 500 µV
Discharges shift to posterior head regions

Correct answer: The discharges become fragmented, irregular, and slower (< 2.5 Hz) over time

During prolonged absence status epilepticus, the initially regular 3-Hz spike-and-wave tends to slow, fragment, and become irregular as status continues.

Question 176: During a routine EEG on a 25-year-old patient, the technologist observes intermittent bursts of 7-11 Hz, arch-shaped waves over the central head regions (C3, C4, Cz). This activity disappears when the patient is asked to make a fist. What normal EEG variant is being described?

Mu rhythm (Correct answer)
Posterior slow waves of youth
Lambda waves
Sleep spindles

Correct answer: Mu rhythm

The Mu rhythm is a normal variant found in the alpha frequency range (typically 7-11 Hz) with a characteristic arch-like or comb shape. It is located over the central regions (sensorimotor cortex) and is uniquely blocked or attenuated by contralateral motor activity, the thought of movement, or tactile stimulation, but not by eye opening.

Question 177: The 'N13' potential recorded at the cervical spine (Cv5 or Cv7 electrode) during median nerve SSEP is generated by which structure?

Ventral posterior lateral thalamus
Primary somatosensory cortex
Dorsal horn/dorsal column nuclei at the cervicomedullary junction (Correct answer)
Brachial plexus Erb's point

Correct answer: Dorsal horn/dorsal column nuclei at the cervicomedullary junction

N13 is a stationary far-field potential reflecting synaptic activity at the dorsal column nuclei (cuneate nucleus) in the cervicomedullary junction, serving as an important reference point for central conduction.

Question 178: What montage is typically used as the initial display for reviewing a routine EEG?

Bipolar longitudinal (double banana) montage (Correct answer)
Bipolar transverse montage
Laplacian montage
Average reference montage

Correct answer: Bipolar longitudinal (double banana) montage

The bipolar longitudinal (double banana) montage is the standard starting point for EEG review because it provides systematic anterior-to-posterior coverage, clear phase reversals for localization, and intuitive left-right comparison.

Question 179: How can chewing artifact be distinguished from rhythmic temporal seizure activity?

They cannot be distinguished without video monitoring
Chewing artifact is always lower in amplitude than seizure activity
Chewing artifact only appears in posterior channels
Chewing artifact produces bilateral, symmetrical, rhythmic EMG bursts with a chewing rhythm (1-2 Hz) that correlates with observed jaw movements (Correct answer)

Correct answer: Chewing artifact produces bilateral, symmetrical, rhythmic EMG bursts with a chewing rhythm (1-2 Hz) that correlates with observed jaw movements

Chewing artifact produces bilateral, relatively symmetrical EMG activity at temporal electrodes with a rhythmic pattern matching jaw movements, while temporal seizure activity typically shows evolving frequency and may have associated epileptiform features.

Question 180: AAN guidelines recommend that ECI be recorded for a minimum duration of how many minutes of technically satisfactory tracing?

20 minutes
10 minutes
60 minutes
30 minutes (Correct answer)

Correct answer: 30 minutes

A minimum of 30 minutes of technically adequate recording is required. This duration helps ensure that any intermittent low-amplitude cerebral activity is not missed due to sampling too brief a window, and it provides a sufficient record for independent clinical review.

Question 181: What feature best distinguishes a benign epileptiform transient of sleep (BETS) from a pathological epileptiform discharge?

BETS have a duration greater than 200 milliseconds
BETS always appear in the frontal regions
BETS occur only during REM sleep
BETS are typically small, isolated, and lack an after-going slow wave (Correct answer)

Correct answer: BETS are typically small, isolated, and lack an after-going slow wave

BETS (also known as small sharp spikes or SSS) are low-amplitude, brief, isolated transients without after-going slow waves, occurring during drowsiness and light sleep, and are considered benign normal variants.

Question 182: Wave with a single deviation from the baseline, either up or down.

Monophasic (Correct answer)
Paroxysmal
Polyphasic
Epileptiform

Correct answer: Monophasic

Monophasic waves have only one deflection from the baseline, either up or down. This indicates that there is just one phase or direction of deflection for the wave. Unlike the other alternatives, it does not contain many phases or deflections (transient, polyphasic, paroxysmal, epileptiform).

Question 183: The lambda wave is a positive sharp transient that occurs in the occipital region during:

Hyperventilation
Eye closure in a dark room
Deep sleep stage N3
Active visual scanning of a complex image or environment (Correct answer)

Correct answer: Active visual scanning of a complex image or environment

Lambda waves are positive sharp transients over the occipital regions that occur during visual scanning with saccadic eye movements. They represent cortical responses to visual input during active looking.

Question 184: Which of the following non-epileptiform patterns is characterized by its location over the sensorimotor cortex, a frequency of 8-10 Hz, an arciform or comb-like morphology, and its attenuation with contralateral limb movement or the thought of movement?

Posterior Dominant Rhythm (Alpha)
Lambda Waves
Rhythmic Mid-Temporal Theta of Drowsiness (RMTD)
Mu Rhythm (Correct answer)

Correct answer: Mu Rhythm

The Mu rhythm is the idling rhythm of the sensorimotor cortex. It is defined by its central location (C3, Cz, C4), alpha-range frequency (typically 8-10 Hz), arc-like shape, and its unique reactivity—it blocks or attenuates with contralateral motor activity, imagined motor activity, or tactile stimulation, but not with eye-opening. [21, 29, 39]

Question 185: What is the primary purpose of the 'biological calibration' signal used in EEG systems?

To calibrate the ink-jet speed of the chart recorder
To set the low-frequency filter cutoff automatically
To verify the amplifier gain using a known physiological signal (Correct answer)
To eliminate 60 Hz interference from the recording

Correct answer: To verify the amplifier gain using a known physiological signal

Biological calibration uses a known physiological signal (such as eye blink artifact) to verify that amplifier gain and channel balance are consistent across all channels.

Question 186: The reticular activating system (RAS) primarily influences EEG by:

Generating the posterior dominant rhythm directly
Producing sleep spindles during REM sleep
Creating focal delta activity over the brainstem
Modulating cortical arousal and desynchronization through ascending projections to the thalamus and cortex (Correct answer)

Correct answer: Modulating cortical arousal and desynchronization through ascending projections to the thalamus and cortex

The reticular activating system in the brainstem modulates the level of cortical arousal through ascending projections to the thalamus and diffuse cortical projections, switching the EEG between synchronized (sleep) and desynchronized (wake) patterns.

Question 187: Which peripheral nerve is most commonly stimulated at the ankle when performing lower extremity somatosensory evoked potential (SSEP) testing?

Sciatic nerve
Common peroneal nerve
Posterior tibial nerve (Correct answer)
Femoral nerve

Correct answer: Posterior tibial nerve

The posterior tibial nerve at the medial ankle is the standard lower extremity stimulus site because it is superficial, easily palpated, and activates large-diameter sensory fibers with reliable cortical responses.

Question 188: The phenomenon of 'REM rebound' after REM-suppressing medication withdrawal is best explained by:

Cholinergic receptor downregulation
Homeostatic pressure accumulating during REM deprivation (Correct answer)
Increased slow-wave sleep drive
Circadian rhythm advancement

Correct answer: Homeostatic pressure accumulating during REM deprivation

When REM-suppressing drugs are withdrawn, accumulated homeostatic REM pressure results in increased REM percentage and shortened REM latency.

Question 189: During a portable EEG in the ICU, the patient experiences a generalized tonic-clonic seizure. After ensuring the patient is safe and calling for nursing assistance, what is the technologist's primary responsibility related to the recording?

Continue recording and meticulously document all clinical manifestations and the exact time they occur. (Correct answer)
Protect the EEG machine from being damaged by the patient's movements.
Administer stand-by medication as ordered in the patient's chart.
Immediately stop the recording to prevent movement artifact from obscuring the data.

Correct answer: Continue recording and meticulously document all clinical manifestations and the exact time they occur.

The technologist's primary role during a seizure is to ensure patient safety first, then to obtain a high-quality recording of the clinical and electrographic event. Accurately annotating the recording with observed clinical signs (e.g., 'tonic stiffening of all limbs,' 'head turn to left,' 'clonic jerking of right arm') is crucial for the interpreting physician. Stopping the recording would mean losing the most critical diagnostic data. Administering medication is outside the technologist's scope of practice.

Question 190: What is the standard stimulus rate used when performing pattern reversal visual evoked potentials (VEPs) in a clinical setting?

10–15 reversals/second
0.1–0.5 reversals/second
1–2 reversals/second (Correct answer)
5–8 reversals/second

Correct answer: 1–2 reversals/second

A reversal rate of approximately 1–2 per second (1–2 Hz) is standard for pattern reversal VEPs; faster rates can cause habituation and distort the P100 latency.

Question 191: The Laplacian (source derivation) montage differs from standard montages by:

Using only two electrodes total
Displaying raw unreferenced voltage from each electrode
Only using midline electrodes
Subtracting the weighted average of surrounding electrodes from each electrode, enhancing focal activity and suppressing diffuse activity (Correct answer)

Correct answer: Subtracting the weighted average of surrounding electrodes from each electrode, enhancing focal activity and suppressing diffuse activity

The Laplacian montage estimates the second spatial derivative of the surface potential by subtracting the weighted average of surrounding electrodes from each electrode, effectively acting as a spatial high-pass filter that enhances focal sources and suppresses widespread activity.

Question 192: Lambda waves in the EEG are best elicited by which condition?

Voluntary limb movement
Auditory stimulation
Eye closure in a dark room
Active visual scanning of a patterned surface (Correct answer)

Correct answer: Active visual scanning of a patterned surface

Lambda waves are positive occipital transients that occur during active visual scanning (saccadic eye movements) of a patterned scene.

Question 193: Which of the following features best distinguishes tremor artifact from a true EEG rhythm?

Tremor artifact is always frontally predominant
Tremor artifact only appears in referential montages
Tremor artifact shows phase reversal in bipolar montages
Tremor artifact has a fixed frequency matching the patient's tremor rate (Correct answer)

Correct answer: Tremor artifact has a fixed frequency matching the patient's tremor rate

Tremor artifact mirrors the physiological tremor frequency (4–6 Hz for Parkinson's, 8–12 Hz for essential tremor) and correlates with observed limb movement.

Question 194: A critically ill patient is being actively cooled to 33°C for targeted temperature management after cardiac arrest. How does this temperature affect the EEG?

Has no effect on EEG background until temperature drops below 20°C
Selectively abolishes sleep spindles while preserving alpha activity
Produces diffuse high-amplitude delta without affecting frequency
Progressively slows and suppresses EEG activity; may produce burst suppression or ECI at very low temperatures (Correct answer)

Correct answer: Progressively slows and suppresses EEG activity; may produce burst suppression or ECI at very low temperatures

Hypothermia is a potent EEG suppressant. At 33°C, background slowing and decreased amplitude are expected. As temperature falls further (below ~20°C), burst suppression and eventually ECI can occur — all reversible with rewarming. Failure to account for hypothermia when interpreting EEGs leads to false prognostication.

Question 195: The N20 component of the median nerve SSEP is primarily generated by which brain structure?

Primary somatosensory cortex (Area 3b, S1) (Correct answer)
Thalamus (ventral posterior lateral nucleus)
Supplementary motor area
Parietal association cortex (Area 7)

Correct answer: Primary somatosensory cortex (Area 3b, S1)

N20 reflects the initial thalamocortical volley arriving at primary somatosensory cortex (Brodmann area 3b) on the posterior bank of the central sulcus.

Question 196: A rhythmic artifact at exactly 60 Hz appearing uniformly across all electrodes is most consistent with:

Cardiac artifact
Electrode pop
AC line noise (Correct answer)
Muscle artifact

Correct answer: AC line noise

60 Hz AC line noise appears as a uniform, rhythmic interference at power line frequency across all or many electrodes.

Question 197: Which of the following filter combinations would be most appropriate for routine clinical EEG recording to visualize cortical activity while minimizing slow-wave artifact and high-frequency noise?

Low-Frequency Filter (LFF) at 1 Hz, High-Frequency Filter (HFF) at 35 Hz
Low-Frequency Filter (LFF) at 5 Hz, High-Frequency Filter (HFF) at 70 Hz
Low-Frequency Filter (LFF) at 1 Hz, High-Frequency Filter (HFF) at 70 Hz (Correct answer)
Low-Frequency Filter (LFF) at 0.1 Hz, High-Frequency Filter (HFF) at 15 Hz

Correct answer: Low-Frequency Filter (LFF) at 1 Hz, High-Frequency Filter (HFF) at 70 Hz

Standard settings for routine EEG are a Low-Frequency Filter (LFF) of 1 Hz and a High-Frequency Filter (HFF) of 70 Hz. This 'band-pass' allows the typical range of cerebral frequencies (1-70 Hz) to be displayed while attenuating very slow activity (like sweat artifact) and very high-frequency activity (like muscle artifact). Setting the LFF too high (e.g., 5 Hz) can filter out clinically relevant delta activity, and setting the HFF too low (e.g., 15 or 35 Hz) can filter out fast activity like spikes or beta.

Question 198: Impedance testing of EEG electrodes should ideally be performed using:

Visual inspection of electrode gel application
An alternating current (AC) impedance meter at a frequency similar to the signals of interest (Correct answer)
A standard multimeter in resistance mode
A direct current (DC) impedance meter

Correct answer: An alternating current (AC) impedance meter at a frequency similar to the signals of interest

AC impedance measurement at frequencies relevant to EEG (typically 10-30 Hz) is preferred because it accounts for the capacitive and resistive components of electrode impedance and avoids DC polarization that could affect recording quality.

Question 199: An average reference montage calculates each channel's display by:

Comparing left hemisphere electrodes to right hemisphere
Using a weighted sum based on electrode distance
Subtracting the computed average of all electrode voltages from each electrode (Correct answer)
Subtracting the voltage of the nearest neighbor electrode

Correct answer: Subtracting the computed average of all electrode voltages from each electrode

The average reference uses the arithmetic mean of all active electrodes as the reference point. Each channel displays the difference between one electrode and this common average, providing a relatively neutral reference.

Question 200: The input impedance of a modern EEG amplifier should be:

Very high, typically greater than 100 megaohms (Correct answer)
Exactly equal to the electrode impedance
As low as possible, ideally under 100 ohms
Between 1 and 5 kilohms

Correct answer: Very high, typically greater than 100 megaohms

Modern EEG amplifiers have very high input impedance (>100 megaohms) to minimize current draw from the scalp electrodes, ensuring accurate voltage measurement without loading the source.

Question 201: Which evoked potential modality is specifically used to assess the integrity of the auditory pathway from the cochlea through the brainstem?

Somatosensory Evoked Potentials (SSEP)
Visual Evoked Potentials (VEP)
Brainstem Auditory Evoked Potentials (BAEP) (Correct answer)
Motor Evoked Potentials (MEP)

Correct answer: Brainstem Auditory Evoked Potentials (BAEP)

BAEPs (also called ABRs) record far-field potentials generated along the auditory nerve and brainstem from cochlea to inferior colliculus.

ABRET R.EEG.T. Exam

The ABRET R.EEG.T. (Registered Electroencephalographic Technologist) exam certifies competency in performing and interpreting electroencephalographic recordings, covering electrode placement, normal and abnormal waveform recognition, instrumentation, patient safety, and neuroanatomy.

200

Questions

180 min

Time Limit

70%

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