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

Question 1: 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 2: 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:

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

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 3: The 'sensitivity' setting on an EEG machine refers to:

The voltage per unit of pen or display deflection (e.g., µV/mm) (Correct answer)
The number of channels recorded simultaneously
The speed at which the paper or display advances
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 4: Eye blink artifact is primarily seen at which electrode positions?

Occipital electrodes (O1, O2)
Frontal electrodes (Fp1, Fp2) (Correct answer)
Central electrodes (C3, C4)
Temporal electrodes (T3, T4)

Correct answer: Frontal electrodes (Fp1, Fp2)

Eye blink artifact produces high-amplitude positive deflections most prominent at Fp1 and Fp2 because the cornea (positive pole of the eye dipole) moves upward toward these frontopolar electrodes during blinking.

Question 5: Positive occipital sharp transients of sleep (POSTS) are a normal finding seen during which sleep state?

Deep slow-wave sleep (N3)
NREM light sleep (N1-N2) (Correct answer)
REM sleep only
Wakefulness with eyes open

Correct answer: NREM light sleep (N1-N2)

POSTS are surface-positive sharp transients over the occipital regions that appear during light NREM sleep (N1 and N2). They are a normal variant and should not be confused with occipital epileptiform discharges.

Question 6: Pattern-reversal VEPs are preferred over flash VEPs in clinical practice primarily because they:

Require less patient cooperation
Are faster to perform
Do not require specialized equipment
Produce more consistent waveforms with smaller normal variance (Correct answer)

Correct answer: Produce more consistent waveforms with smaller normal variance

Pattern-reversal stimuli generate highly reproducible P100 components with tight normative ranges, making subtle latency delays more detectable than with flash VEPs.

Question 7: A technologist is reviewing an EEG from an awake patient who was asked to scan a complex image. The recording shows bilateral, positive, sharply contoured waves in the occipital channels that occur only during the visual scanning task. These waveforms are most likely:

Positive Occipital Sharp Transients of Sleep (POSTS)
Epileptiform discharges
Lambda waves (Correct answer)
Vertex waves

Correct answer: Lambda waves

Lambda waves are normal, waking phenomena that are time-locked to saccadic eye movements, such as those that occur during visual scanning or reading. They are characteristically positive in polarity, have a sharp or triangular shape, and are located in the occipital regions.

Question 8: High-frequency, irregular bursts of activity seen maximally over temporal and frontal electrodes during a patient interview are most consistent with:

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

Correct answer: Chewing/jaw muscle artifact

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

Question 9: The primary somatosensory cortex, which generates somatosensory evoked potentials recorded by EEG, is located in which gyrus?

Postcentral gyrus (Correct answer)
Angular gyrus
Precentral gyrus
Superior temporal gyrus

Correct answer: Postcentral gyrus

The postcentral gyrus (Brodmann areas 1, 2, 3) constitutes primary somatosensory cortex and is the main generator of early cortical SEP components.

Question 10: 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)
Rhythmic 8 Hz sinusoidal waves in the Fp1 and Fp2 channels.
High-amplitude, synchronous slow waves in all frontal channels.
A sharp positive deflection at F7 and a sharp negative deflection at F8.

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 11: What is the primary advantage of using an average reference montage?

It best localizes focal epileptiform discharges
It reduces the number of electrodes required
It eliminates the need for impedance checks
It reduces bias from any single reference electrode location (Correct answer)

Correct answer: It reduces bias from any single reference electrode location

The average reference montage uses the average of all electrodes as the reference, which reduces the distortion that can occur when a single reference electrode is near active brain tissue.

Question 12: The recommended minimum number of EEG channels for a routine clinical recording is:

8 channels
64 channels
32 channels
16 channels (plus ECG, EOG) (Correct answer)

Correct answer: 16 channels (plus ECG, EOG)

The ACNS recommends a minimum of 16 EEG channels for routine clinical recording, derived from 21 electrodes in the 10-20 system, plus additional channels for ECG, EOG, and other polygraphic recordings.

Question 13: Occipital intermittent rhythmic delta activity (OIRDA) in a child is most commonly associated with:

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

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

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

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 15: An EEG is performed on a 32-week conceptional age premature infant. During quiet sleep, the recording shows bursts of high-amplitude mixed frequencies lasting 3-10 seconds, separated by periods of marked attenuation (<25 µV) lasting 10-20 seconds. This pattern is best described as:

Tracé alternant
Hypsarrhythmia
Burst-suppression
Tracé discontinu (Correct answer)

Correct answer: Tracé discontinu

Tracé discontinu is the characteristic EEG pattern of quiet sleep in premature infants between approximately 30 and 34 weeks conceptional age. It consists of bursts of mixed-frequency activity separated by interburst intervals of significant voltage attenuation, typically less than 25 µV. [1, 2, 3] Tracé alternant is seen in older infants (around 34-44 weeks) and has a higher interburst interval amplitude (>25 µV). Burst-suppression is a profoundly abnormal pattern associated with severe encephalopathy. Hypsarrhythmia is a chaotic, high-voltage, disorganized pattern seen in infants with West syndrome.

Question 16: A patient with uremic encephalopathy undergoes EEG. Which pattern would be an expected non-epileptiform abnormality in this setting?

Prominent alpha activity at 10–12 Hz
Well-organized posterior dominant rhythm
Persistent beta spindle activity
Diffuse theta-delta slowing with possible triphasic waves (Correct answer)

Correct answer: Diffuse theta-delta slowing with possible triphasic waves

Uremic encephalopathy typically produces diffuse background slowing into the theta and delta ranges, sometimes with triphasic morphology similar to hepatic encephalopathy.

Question 17: Which of the following is the LEAST likely cause of persistent 60 Hz electrical interference in an EEG recording?

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

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

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

Correct answer: Slow sweat artifact

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

Question 19: Cortical somatosensory evoked potentials recorded over the scalp after median nerve stimulation include which early obligate component?

P40
N13
N20 (Correct answer)
N9

Correct answer: N20

N20 is the first cortical (primary somatosensory cortex) component of the median nerve SSEP, typically appearing ~20 ms post-stimulus in adults.

Question 20: In a comatose patient, the presence of sleep architecture elements such as sleep spindles or K-complexes on EEG suggests which prognostic implication?

Certain poor outcome
Imminent seizure activity
Relatively preserved thalamocortical function and potentially better prognosis (Correct answer)
Electrocerebral inactivity

Correct answer: Relatively preserved thalamocortical function and potentially better prognosis

Preservation of sleep architecture in coma indicates intact thalamocortical circuitry and generally correlates with a more favorable neurological prognosis.

Question 21: Electrocerebral inactivity (ECI) on EEG requires that no cerebral electrical activity exceed what amplitude threshold?

10 µV
20 µV
2 µV (Correct answer)
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 22: 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 0.1 Hz, High-Frequency Filter (HFF) at 15 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 1 Hz, High-Frequency Filter (HFF) at 35 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 23: In the revised IFCN electrode nomenclature, electrode T5 is now called:

P5
TP7
T7
P7 (Correct answer)

Correct answer: P7

In the revised nomenclature, T5 was renamed P7 because it overlies the posterior temporal/parietal region, not the mid-temporal region.

Question 24: When performing EEG on a patient with an implanted cardiac defibrillator (ICD), the technologist should:

Only use 4 electrodes to minimize electromagnetic interference
Refuse to perform the study as it is absolutely contraindicated
Proceed with the study using standard technique, as EEG does not interfere with ICDs, but be aware the ICD may produce artifact on the ECG channel (Correct answer)
Deactivate the ICD before starting the recording

Correct answer: Proceed with the study using standard technique, as EEG does not interfere with ICDs, but be aware the ICD may produce artifact on the ECG channel

EEG is safe to perform on patients with ICDs as EEG equipment does not generate electromagnetic fields that could interfere with the device. The ICD may produce artifact on the ECG channel that should be recognized.

Question 25: Which cognitive evoked potential component is considered the gold standard for assessing auditory discrimination and working memory?

N400
P300 (P3b) (Correct answer)
N100
P200

Correct answer: P300 (P3b)

The P300 (P3b) is an endogenous, task-related component elicited by target detection in an oddball paradigm, widely used to assess cognitive processing speed and memory.

Question 26: An EEG electrode placed at C3, according to the International 10-20 System, primarily records activity from which cortical region?

The primary motor and somatosensory cortex (Brodmann areas 4, 1, 2, 3) (Correct answer)
The primary visual cortex (Brodmann area 17)
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 27: Which neonatal seizure type is most commonly electrographic-only (without clinical correlate) and therefore detectable only by EEG?

Clonic seizures
Subtle seizures
Tonic seizures
Electrographic-only (subclinical) seizures (Correct answer)

Correct answer: Electrographic-only (subclinical) seizures

Subclinical (electrographic-only) seizures in neonates have no visible clinical manifestation and can only be detected through continuous EEG monitoring.

Question 28: Which neurotransmitter released by basal forebrain neurons desynchronizes the EEG and promotes wakefulness by depolarizing cortical neurons?

GABA
Acetylcholine (Correct answer)
Glycine
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 29: Which montage type is most useful for localizing the PHASE REVERSAL of an epileptiform discharge?

Bipolar montage (Correct answer)
Referential montage
Average reference montage
Laplacian montage

Correct answer: Bipolar montage

Bipolar montages are best for localizing epileptiform discharges because phase reversals occur at the electrode directly over the focus.

Question 30: In juvenile myoclonic epilepsy (JME), the EEG hallmark is polyspike-and-wave discharges typically at which frequency?

1–2 Hz
4–6 Hz (Correct answer)
10–12 Hz
3 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 31: Gamma oscillations (>30 Hz) in the normal EEG are most associated with which cognitive state?

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

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 32: A patient who speaks only Spanish arrives for an EEG and the technologist speaks only English. Which approach best upholds informed consent standards?

Arrange a qualified medical interpreter (in person, phone, or video) before obtaining consent (Correct answer)
Provide a written consent form in English and have the patient sign it
Use the patient's adult family member as an informal interpreter for the consent discussion
Proceed without explanation since the procedure is non-invasive

Correct answer: Arrange a qualified medical interpreter (in person, phone, or video) before obtaining consent

Informed consent requires that the patient fully understands the procedure, which necessitates a qualified medical interpreter — not a family member — to avoid conflict of interest and ensure accuracy.

Question 33: The lateral sulcus (Sylvian fissure) separates the frontal and parietal lobes above from which lobe below?

Insular lobe
Limbic lobe
Occipital lobe
Temporal lobe (Correct answer)

Correct answer: Temporal lobe

The lateral sulcus separates the frontal and parietal lobes superiorly from the temporal lobe inferiorly.

Question 34: 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?

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

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 35: 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?

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

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

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

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

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

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 38: Muscle artifact from the temporalis muscle can be distinguished from beta activity because muscle artifact typically:

Shows frequencies above 20 Hz with irregular sharp morphology maximal at temporal electrodes (Correct answer)
Has a frequency below 8 Hz
Appears only during sleep
Is enhanced by hyperventilation

Correct answer: Shows frequencies above 20 Hz with irregular sharp morphology maximal at temporal electrodes

Temporalis muscle (EMG) artifact produces high-frequency (typically >20 Hz) irregular, sharp activity maximal at temporal and frontal electrodes, which can obscure underlying brain activity in those regions.

Question 39: Which EEG pattern is characterized by a spike followed by a slow wave complex occurring at approximately 3 Hz?

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

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 40: Which EEG feature is the hallmark of Stage N2 sleep?

Delta waves >75 µV
Sawtooth waves
Alpha rhythm dropout
Sleep spindles and K-complexes (Correct answer)

Correct answer: Sleep spindles and K-complexes

Stage N2 sleep is defined by the presence of sleep spindles (12–14 Hz bursts) and K-complexes on EEG.

Question 41: 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?

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

Correct answer: Sleep spindle

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

Question 42: A normal adult EEG background shows a well-organized 10 Hz posterior dominant rhythm. This rhythm is categorized as which frequency band?

Theta
Low beta
Sigma
Alpha (Correct answer)

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 43: An EEG technologist discovers that a colleague has been omitting seizure events from written reports to speed up throughput. What is the most appropriate course of action?

Report the concern through the facility's established chain of command or compliance channel (Correct answer)
Ignore it since the interpreting physician will catch any errors
Confront the colleague privately and ask them to stop
Begin correcting the colleague's reports without disclosure

Correct answer: Report the concern through the facility's established chain of command or compliance channel

Omitting clinical data is an ethical and potentially legal violation requiring formal reporting through proper institutional channels.

Question 44: An asymmetry in the posterior dominant rhythm amplitude, with the right side consistently 50% lower than the left, suggests:

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

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 45: Which of the following electrographic features is most characteristic of an ictal event (electrographic seizure) in a full-term neonate?

Bilaterally synchronous and symmetric sleep spindles.
Intermittent, asynchronous bursts of high-voltage slow waves mixed with spikes (Hypsarrhythmia).
A sustained, rhythmic, evolving pattern of sharp waves or delta activity lasting more than 10 seconds. (Correct answer)
Generalized, synchronous 3 Hz spike-and-wave discharges.

Correct answer: A sustained, rhythmic, evolving pattern of sharp waves or delta activity lasting more than 10 seconds.

The gold standard for identifying a neonatal electrographic seizure is the presence of a sustained, rhythmic discharge that shows clear evolution in frequency, morphology, or location and lasts for at least 10 seconds. [5, 26] Neonatal seizures are typically focal in onset and can consist of various morphologies, including rhythmic delta or sharp activity. [5] Generalized 3 Hz spike-and-wave is typical of absence seizures in older children, hypsarrhythmia is an interictal pattern, and sleep spindles are normal sleep architecture.

Question 46: During photic stimulation, the technologist notices the patient becoming agitated and the EEG shows generalized spike-and-wave activity outlasting the flash trains. The appropriate action is to:

Switch to hyperventilation immediately
Continue stimulation to determine the full extent of the response
Increase the flash frequency to get a better sample of the response
Immediately stop photic stimulation and continue recording the after-discharge (Correct answer)

Correct answer: Immediately stop photic stimulation and continue recording the after-discharge

A photoparoxysmal response that outlasts the stimulus (Type 4) is clinically significant and stimulation should be stopped immediately to prevent triggering a clinical seizure, while continuing to record the EEG.

Question 47: During sleep recording, repetitive, high-amplitude spike-like potentials appearing synchronously with each heartbeat across all leads are best identified as:

Cardiac (EKG) artifact (Correct answer)
K-complexes
Frontal arousal rhythms
Vertex sharp waves

Correct answer: Cardiac (EKG) artifact

EKG artifact produces spike-like potentials synchronous with the R-wave, often mistaken for epileptiform discharges if the ECG channel is not reviewed.

Question 48: An EEG amplifier has a CMRR of 100 dB. This means the amplifier rejects common-mode signals by a factor of approximately:

1,000 times
10,000 times
100 times
100,000 times (Correct answer)

Correct answer: 100,000 times

100 dB CMRR means common-mode signals are rejected by a factor of 10^(100/20) = 100,000 times relative to the differential signal.

Question 49: 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 milliseconds
> 200 milliseconds
70-200 milliseconds (Correct answer)
20-70 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 50: The 'mu rhythm' seen over the central scalp in a relaxed, awake subject has a frequency overlapping with which other rhythm?

Gamma
Theta
Alpha (Correct answer)
Delta

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 51: In the 10-20 system, which electrode is located at the vertex of the skull?

Fz
Pz
Cz (Correct answer)
C3

Correct answer: Cz

Cz is located at the vertex (top) of the skull at the intersection of the midline and a line connecting the two ears.

Question 52: 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 53: 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)
Amplitude exceeding 100 µV
Occurrence during active sleep
Presence of a post-ictal suppression lasting 1 second

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

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

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 55: 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 56: K-complexes are characterized by which of the following features?

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
Bilateral occipital alpha bursts during drowsiness

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 57: Which measurement is most commonly used to identify BAEP abnormalities related to central conduction?

Stimulus intensity threshold
Absolute wave I latency alone
Peak-to-trough amplitudes
Interpeak latencies (IPLs) between waves (Correct answer)

Correct answer: Interpeak latencies (IPLs) between waves

Interpeak latencies (e.g., I–III, III–V, I–V) reflect central conduction time between brainstem generators and are the primary diagnostic parameters for central pathology.

Question 58: Which of the following best describes the neurophysiological basis for why a minimum cortical area of approximately 6-20 cm² must be synchronously activated to generate a detectable scalp EEG signal?

The high electrical impedance of the cerebrospinal fluid
The requirement for bilateral hemispheric involvement for any recordable potential
The specific firing frequency of pyramidal neurons
The filtering effect of the skull and scalp, which attenuates small or asynchronous signals (Correct answer)

Correct answer: The filtering effect of the skull and scalp, which attenuates small or asynchronous signals

The skull, dura, and scalp act as low-pass filters and have high electrical resistance, a process known as volume conduction. This significantly attenuates the electrical potentials generated by the brain. Therefore, a large area of cortex with thousands of neurons firing synchronously is required to produce a signal strong enough to overcome this impedance and be detected by scalp electrodes.

Question 59: An artifact appearing as a rhythmic, 1–3 Hz broad, high-amplitude slow-wave pattern that correlates with the patient's assisted ventilation rate is called:

Movement artifact
Ventilator artifact (Correct answer)
Cardiac artifact
Tremor artifact

Correct answer: Ventilator artifact

Ventilator artifact is caused by rhythmic chest and head movement from mechanical ventilation, producing slow waves at the ventilation rate.

Question 60: A flatline EEG tracing recorded at 2 µV/mm sensitivity is most likely artifactual rather than true ECI if which finding is present?

Symmetric suppression bilaterally across all electrode pairs
No change with photic stimulation at 1 Hz
Activity that disappears when the technologist lifts the patient's arm off the bed (Correct answer)
No activity in a bipolar longitudinal montage

Correct answer: Activity that disappears when the technologist lifts the patient's arm off the bed

If apparent flatline activity disappears when a potential movement artifact source (such as the patient's arm resting against the bed or equipment) is removed, the 'activity' was movement or ECG artifact rather than true cerebral electrical potentials. True ECI persists regardless of patient position adjustments.

Question 61: Which technical factor most directly degrades SSEP and BAEP signal quality by introducing 60 Hz noise and poor signal-to-noise ratio?

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

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 62: An 8-year-old child presents with frequent staring spells. The EEG recording shows bursts of generalized, synchronous, and symmetric 3 Hz spike-and-wave discharges that are easily provoked by hyperventilation. What is the most likely clinical correlation?

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

Correct answer: Childhood absence epilepsy

The classic EEG signature for typical childhood absence epilepsy is generalized, symmetric 3 Hz spike-and-wave discharges, often induced by hyperventilation, which correlates clinically with brief staring spells. Lennox-Gastaut syndrome presents with slow (<2.5 Hz) spike-and-wave, Benign Rolandic epilepsy shows focal centrotemporal spikes, and Juvenile myoclonic epilepsy typically has faster (>3 Hz) polyspike-and-wave discharges.

Question 63: The N400 event-related potential is characteristically elicited by:

Unexpected tones in an auditory oddball task
Visual pattern reversal
Painful cutaneous stimulation
Semantically incongruent words in a sentence (Correct answer)

Correct answer: Semantically incongruent words in a sentence

The N400 is a negative deflection peaking ~400 ms that reflects semantic mismatch processing, elicited when a word violates the expected meaning of a sentence.

Question 64: What is the significance of a markedly asymmetric background in neonatal EEG?

It is a normal variant in preterm neonates
It is diagnostic of neonatal epilepsy
It indicates artifact from electrode placement
It suggests ipsilateral hemispheric injury or contralateral hemispheric dysfunction (Correct answer)

Correct answer: It suggests ipsilateral hemispheric injury or contralateral hemispheric dysfunction

Persistent interhemispheric amplitude asymmetry (>50%) in a neonate suggests structural injury on the side with attenuated activity or dysfunction on the opposite side.

Question 65: 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 appear shorter. (Correct answer)
The spike will appear taller.
The spike's appearance will not change.
The spike will become wider.

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

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

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 67: Glossokinetic artifact is caused by movement of which structure?

The diaphragm during breathing
The tongue, which acts as an electrical dipole (Correct answer)
The scalp muscles during frowning
The jaw muscles during chewing

Correct answer: The tongue, which acts as an electrical dipole

The tongue has a tip-negative, base-positive electrical dipole. Tongue movements generate slow potentials that are transmitted to scalp electrodes, particularly in frontal and temporal regions.

Question 68: The beta wave frequency is

13–30 Hertz (Correct answer)
6–10 Hertz
Higher than 45 Hz
Over 13 Hertz

Correct answer: 13–30 Hertz

Neural oscillations in the brain called beta waves are linked to attentiveness, focus, and proactive thought processes. Their usual frequency range is between 13 and 30 Hertz.

Question 69: A photic driving response seen on EEG during IPS is considered normal when it occurs at:

Frequencies above 60 Hz
Harmonic or subharmonic frequencies of the flash rate over the occipital region (Correct answer)
Frontal regions only at any frequency
Only during simultaneous HV

Correct answer: Harmonic or subharmonic frequencies of the flash rate over the occipital region

Normal photic driving is a rhythmic occipital response at the flash frequency or its harmonics/subharmonics and represents normal visual cortex activation.

Question 70: What is the maximum recommended electrode impedance for routine EEG recording according to ACNS guidelines?

5 kOhm (Correct answer)
1 kOhm
10 kOhm
20 kOhm

Correct answer: 5 kOhm

The American Clinical Neurophysiology Society recommends electrode impedances be below 5 kOhm and balanced across all electrodes to optimize signal quality and common-mode rejection.

Question 71: 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?

Mu rhythm
Beta rhythm
Alpha rhythm (Correct answer)
Theta 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 72: Which VEP component is most commonly used clinically to detect demyelinating disease of the optic nerve?

P200
N145
P100 (Correct answer)
N75

Correct answer: P100

The P100 component of the VEP is the most clinically relevant peak; a delayed latency (>115 ms) strongly suggests optic nerve demyelination.

Question 73: Which EEG feature differentiates true electrocerebral inactivity from a technical artifact producing an isoelectric-appearing record?

Recording for exactly 20 minutes
Switching to referential montage only
Performing a photic stimulation test
Increasing interelectrode distances, confirming low impedances, and testing reactivity with painful stimuli (Correct answer)

Correct answer: Increasing interelectrode distances, confirming low impedances, and testing reactivity with painful stimuli

Confirming ECI requires technical verification including electrode impedances <10 kΩ, interelectrode distance ≥10 cm, high sensitivity settings, and absence of reactivity to stimulation.

Question 74: Which statement about electrode impedance is correct for clinical EEG?

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

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 75: A wave consisting of three parts that alternate around the baseline.

Polyphasic
Triphasic (Correct answer)
Monophasic
Transient

Correct answer: Triphasic

A wave that alternates between three components around the baseline is referred to as triphasic. This indicates that the wave is composed of three separate stages, or segments, that alternate in a cyclical manner. This phrase is frequently used to characterize certain electrical or physiological waveforms, such as those in muscle activity or nerve transmission, in medical and physiological contexts.

Question 76: The common mode rejection ratio (CMRR) of an EEG differential amplifier measures its ability to:

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

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 77: Inhibitory postsynaptic potentials (IPSPs) on apical dendrites of cortical pyramidal neurons generate which polarity at the overlying scalp electrode?

Positive deflection (Correct answer)
Negative deflection
Biphasic spike
No detectable signal

Correct answer: Positive deflection

IPSPs at apical dendrites create a current sink deeper in the cortex and a source near the surface, resulting in a positive polarity at the scalp electrode above.

Question 78: A patient's qEEG panel shows the asymmetry index trending toward the right hemisphere for 45 minutes. This means:

Seizure activity is more likely occurring over the right hemisphere
The right hemisphere has relatively more power (amplitude) than the left during this period (Correct answer)
Electrode impedance is higher on the right side, inflating apparent amplitude
The left hemisphere's EEG is being contaminated by right-sided muscle artifact

Correct answer: The right hemisphere has relatively more power (amplitude) than the left during this period

An asymmetry index that trends toward one hemisphere indicates that hemisphere has proportionally greater spectral power. Persistent rightward asymmetry over 45 minutes could reflect focal seizure activity, cortical spreading depression, or a structural lesion increasing amplitude on that side. It triggers review of the raw EEG to determine the cause, but by definition it means relatively higher power on the right.

Question 79: What does the term 'electrocerebral inactivity' (ECI) refer to in EEG?

Intermittent suppression during burst-suppression pattern
Normal low-voltage pattern during deep sleep
Absence of cerebral electrical activity above 2 µV at maximum sensitivity, used as an adjunct in brain death determination (Correct answer)
Background slowing to theta range

Correct answer: Absence of cerebral electrical activity above 2 µV at maximum sensitivity, used as an adjunct in brain death determination

Electrocerebral inactivity is the absence of EEG activity above 2 µV when recorded with maximum sensitivity, interelectrode distances of at least 10 cm, and a recording duration of at least 30 minutes, used as an adjunct test in brain death evaluation.

Question 80: Which EEG channel is most useful for identifying and distinguishing eye movement artifacts from frontal brain activity?

Occipital reference channels
Dedicated EOG (electrooculogram) channels (Correct answer)
EMG (electromyogram) channel
ECG channel

Correct answer: Dedicated EOG (electrooculogram) channels

Dedicated EOG channels (typically placed above and below one eye, and at the outer canthi) directly record eye movements and blinks, allowing definitive distinction from frontal cerebral activity.

Question 81: In the setting of acute liver failure, which EEG pattern is characteristic and reflects hepatic encephalopathy grade III-IV?

Frontal dominant triphasic waves with anterior-to-posterior lag (Correct answer)
Bilateral independent periodic lateralized discharges
Occipital dominant spike-wave complexes at 3 Hz
Generalized high-amplitude rhythmic theta activity

Correct answer: Frontal dominant triphasic waves with anterior-to-posterior lag

Triphasic waves with a characteristic anterior-to-posterior phase lag are the classic EEG signature of moderate-to-severe hepatic encephalopathy, reflecting diffuse metabolic cortical dysfunction.

Question 82: Generalized paroxysmal fast activity (GPFA) during slow-wave sleep is the characteristic ictal correlate of which seizure type in Lennox-Gastaut syndrome?

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

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

Medication effect from benzodiazepines
A structural lesion in the right temporal area (Correct answer)
Normal drowsiness
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 84: 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?

Thalamus (Correct answer)
Basal Ganglia
Cerebellum
Hippocampus

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 85: A patient's ambulatory EEG diary notes 'episode of deja vu lasting 30 seconds' at 14:22. The technologist reviewing the recording should FIRST:

Re-apply electrodes before reviewing
Navigate to 14:22 and review the corresponding EEG channel data (Correct answer)
Discard the recording due to subjective symptom reporting
Mark the entire day as artifactual

Correct answer: Navigate to 14:22 and review the corresponding EEG channel data

The technologist should correlate the diary timestamp with the EEG data at that exact time to look for ictal or interictal changes.

Question 86: During hyperventilation activation in EEG, what is the expected normal response in an adult?

Appearance of sleep spindles
Persistent asymmetric delta activity
Focal beta activity increase
Generalized slowing that resolves within 1-2 minutes after cessation (Correct answer)

Correct answer: Generalized slowing that resolves within 1-2 minutes after cessation

Normal hyperventilation response in adults produces bilateral, symmetrical, generalized slowing (buildup) that resolves within 1-2 minutes of stopping. Persistent or asymmetric slowing is abnormal.

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 always considered an abnormal finding in an awake adult.
It is defined as activity in the 4-7 Hz frequency range.
It is typically highest in amplitude in the occipital regions.

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

REM sleep only
Stage N2, N3, and sometimes REM (Correct answer)
Stage N2 and N3
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 89: During EEG setup, electrode impedance is measured and found to be 28 kΩ on electrode F3. The appropriate action is to:

Re-prep the skin and reapply the electrode to reduce impedance (Correct answer)
Switch to a higher-sensitivity amplifier setting for that channel
Apply a notch filter to channel F3 only
Proceed with recording as this is within acceptable range

Correct answer: Re-prep the skin and reapply the electrode to reduce impedance

Standard acceptable electrode impedance is below 5 kΩ (some guidelines allow up to 10 kΩ); 28 kΩ is far too high and requires skin re-preparation and electrode reapplication.

Question 90: A burst suppression pattern on EEG is most consistent with which clinical scenario?

Focal temporal lobe lesion
Benign rolandic epilepsy
Stage II sleep in a healthy adult
Severe diffuse cerebral dysfunction such as deep anesthesia or anoxic brain injury (Correct answer)

Correct answer: Severe diffuse cerebral dysfunction such as deep anesthesia or anoxic brain injury

Burst suppression indicates severely depressed cerebral activity and is seen with deep anesthesia, hypothermia, or severe anoxic-ischemic encephalopathy.

Question 91: What is the normal frequency range of the posterior dominant rhythm (alpha rhythm) in a healthy awake adult?

4-7 Hz
8-13 Hz (Correct answer)
21-30 Hz
14-20 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 92: Sleep spindles are a hallmark of which stage of sleep?

Stage N2 sleep (Correct answer)
Stage N3 (deep slow wave sleep)
Stage N1 (drowsiness)
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 93: Alpha coma is an EEG pattern characterized by:

Widespread, unreactive alpha-frequency activity in a comatose patient, typically following cardiac arrest or brainstem lesion (Correct answer)
Focal alpha activity over a structural lesion
Alpha rhythm that persists during hyperventilation
Normal alpha rhythm in a drowsy but arousable patient

Correct answer: Widespread, unreactive alpha-frequency activity in a comatose patient, typically following cardiac arrest or brainstem lesion

Alpha coma is a paradoxical pattern where widespread, unreactive alpha-frequency activity (8-13 Hz) is present in a comatose patient, most commonly seen after cardiopulmonary arrest or brainstem lesions, and generally carries a poor prognosis.

Question 94: In brainstem auditory evoked potentials (BAEPs), Wave V originates primarily from which structure?

Cochlear nucleus
Medial geniculate body
Superior olivary complex
Lateral lemniscus/inferior colliculus (Correct answer)

Correct answer: Lateral lemniscus/inferior colliculus

Wave V of the BAEP is generated by the lateral lemniscus and inferior colliculus region of the upper brainstem.

Question 95: 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?

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

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

6-7 Hz
9 Hz (Correct answer)
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 97: For pattern reversal visual evoked potential (VEP) testing, how should each eye be stimulated?

With pupils pharmacologically dilated
With both eyes viewing through a red-green filter
Both eyes open simultaneously
Monocularly (one eye at a time, other occluded) (Correct answer)

Correct answer: Monocularly (one eye at a time, other occluded)

Monocular stimulation is essential so that an abnormality in one optic nerve, which lies anterior to the optic chiasm, can be lateralized; binocular stimulation would mask unilateral optic nerve disease.

Question 98: How many electrodes are used in the standard 10-20 system?

19
21 (Correct answer)
25
16

Correct answer: 21

The standard 10-20 system uses 21 electrodes, including 19 scalp electrodes plus A1 and A2 ear reference electrodes.

Question 99: Which pattern is characterized by generalized, bisynchronous rhythmic delta activity seen predominantly over posterior head regions and is a non-epileptiform finding?

OIRDA (Occipital Intermittent Rhythmic Delta Activity) (Correct answer)
GRDA
PLED
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 100: Which epileptiform pattern consists of high-amplitude, chaotic, multifocal spikes and slow waves seen in infantile spasms?

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

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 101: Which artifact is most commonly encountered in ambulatory EEG recordings compared to in-lab studies?

Electrode pop artifact
Movement and muscle artifact (Correct answer)
60 Hz electrical interference
Sweat artifact

Correct answer: Movement and muscle artifact

Movement and muscle artifact are the most common artifacts in ambulatory EEG because patients are performing their normal daily activities, unlike the controlled laboratory environment.

Question 102: What unit of measurement is amplitude?

Gigawatts
Microvolts (Correct answer)
Hertz
Univolts

Correct answer: Microvolts

Microvolts is the unit used to express amplitude. The greatest value of a waveform is referred to as its amplitude, and it is commonly measured in volts. Microvolts are incredibly small units of voltage since the prefix "micro-" denotes one millionth of a voltage. Amplitude is not measured in kilowatts, gigawatts, hertz, or univolts.

Question 103: Which EEG finding is the ictal correlate of epilepsia partialis continua (Kojewnikow syndrome)?

Generalized 3-Hz spike-and-wave
Periodic lateralized epileptiform discharges (PLEDs) at 1–2 Hz
Bilateral independent periodic discharges (BIPDs)
Continuous focal rhythmic delta activity with embedded spikes over the motor cortex (Correct answer)

Correct answer: Continuous focal rhythmic delta activity with embedded spikes over the motor cortex

Epilepsia partialis continua produces continuous or near-continuous focal rhythmic discharges, often with embedded spikes, localized to the contralateral motor cortex.

Question 104: 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
Reports can never be shared with family members
Only after obtaining proper written authorization consistent with HIPAA regulations (Correct answer)
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 105: What does the '10' and '20' refer to in the International 10-20 system?

Frequency bands measured at each site
Number of electrodes in each region
Percentage of total skull distance between electrode sites (Correct answer)
Millimeters between electrodes

Correct answer: Percentage of total skull distance between electrode sites

The 10 and 20 refer to the percentage of the total front-to-back or left-to-right skull distance used as the spacing between electrode positions.

Question 106: Which of the following statements accurately describes the fundamental principle of a bipolar montage?

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.
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.

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 107: In a circumferential (transverse) bipolar montage, electrodes are chained:

From temporal to occipital electrodes only
Around the head from left to right across the coronal plane (Correct answer)
From front to back along the sagittal plane
From each scalp electrode to a common reference

Correct answer: Around the head from left to right across the coronal plane

A transverse (circumferential) bipolar montage chains electrodes in a left-to-right order across the coronal plane, running from one side of the head to the other.

Question 108: The thalamocortical relay neurons that synchronize cortical oscillations and contribute to sleep spindles are located in which thalamic nucleus?

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

Correct answer: Reticular nucleus

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

Question 109: Photomyogenic (photomyoclonic) response, which can mimic a photoparoxysmal response, differs in that it:

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

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

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

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 111: Which cEEG finding in a post-cardiac arrest patient at 72 hours is most predictive of poor neurological outcome, even when therapeutic hypothermia has been applied?

Intermittent generalized slowing with preserved reactivity
Diffuse theta slowing with occasional vertex waves
Persistent burst suppression with isoelectric interburst intervals (Correct answer)
Low-voltage mixed frequency activity

Correct answer: Persistent burst suppression with isoelectric interburst intervals

Persistent burst suppression with flat (isoelectric) interburst intervals at 72 hours post-arrest is one of the strongest EEG predictors of poor neurological prognosis, even after therapeutic hypothermia.

Question 112: What is the recommended distance between the photic stimulator and the patient's eyes during intermittent photic stimulation?

30 cm (Correct answer)
200 cm
100 cm
5 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 113: 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?

5 cm
20 cm
10 cm (Correct answer)
15 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 114: 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?

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

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

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

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

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

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

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 118: 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)
High-Frequency Filter
Sensitivity
Low-Frequency Filter

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 119: During a routine EEG, the technologist observes the patient staring blankly and becoming unresponsive. The appropriate action is to:

Disconnect the electrodes to examine the patient
Continue recording while testing the patient's responsiveness and documenting observations (Correct answer)
Wait until the episode ends to note it in the report
Immediately stop the recording and call a code

Correct answer: Continue recording while testing the patient's responsiveness and documenting observations

The technologist should keep recording to capture the EEG correlate of the clinical event while simultaneously testing responsiveness (speaking to the patient, presenting objects) and carefully documenting all observations with timestamps.

Question 120: 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
Print the record and fax it to the neurologist's personal fax number
Attach the file to a shared public cloud folder for easy access
Use a HIPAA-compliant encrypted platform with patient identifiers limited to the minimum necessary (Correct answer)

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

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

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 122: Which electrode placement system uses 10% and 20% distances from skull landmarks to determine electrode positions?

The International 10-20 system (Correct answer)
The American Clinical Neurophysiology Society (ACNS) system
The Queen Square system
The Modified Combinatorial Nomenclature

Correct answer: The International 10-20 system

The International 10-20 system divides skull circumference into intervals of 10% and 20% from fixed bony landmarks to standardize electrode placement.

Question 123: In the International 10-20 system, what do the numbers 10 and 20 represent?

The number of electrodes used
The percentage of distance between skull landmarks for electrode placement (Correct answer)
The amplifier gain settings
The impedance levels required in kilohms

Correct answer: The percentage of distance between skull landmarks for electrode placement

The 10-20 system places electrodes at 10% and 20% intervals of the measured distances between standardized skull landmarks (nasion, inion, preauricular points).

Question 124: According to the 10-20 International System nomenclature, which electrode would be located over the left mid-temporal region?

T3 (Correct answer)
C3
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 125: In a patient with absent BAEPs bilaterally, which condition is LEAST likely to be the cause?

Bilateral profound sensorineural hearing loss
Cortical stroke sparing the brainstem (Correct answer)
Technical artifact from poor electrode impedance
Brain death

Correct answer: Cortical stroke sparing the brainstem

BAEPs reflect subcortical (brainstem) generators; a cortical stroke that spares the brainstem would preserve all BAEP waves.

Question 126: Waves that are regular and resemble sine waves.

Diphasic
Sinusoidal (Correct answer)
Ictal
Polyphasic

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 127: During a recording of a 25-year-old patient in light sleep, the technologist observes trains of 6-11 Hz arc-shaped (arciform), monophasic waves in the left temporal region. They occur without disrupting the background and are not followed by a slow wave. They sometimes appear as single transients that resemble sharp waves. This pattern is best described as:

Lambda Waves
Wicket Spikes (Correct answer)
Mu Rhythm
Benign Small Sharp Spikes (BSSS/BETS)

Correct answer: Wicket Spikes

Wicket spikes are defined as 6-11 Hz, arc-shaped (arciform), monophasic waves that occur in the temporal regions, especially during drowsiness and light sleep. [2, 35] They can appear in trains or as single transients, which can be easily mistaken for epileptiform sharp waves, but they lack an after-going slow wave and do not disturb the background activity. [33, 35] Mu rhythm is found over the central region and is related to motor activity. [21, 29] BSSS/BETS are lower in amplitude and shorter in duration. [12] Lambda waves are occipital and occur during wakefulness with visual scanning. [1, 38]

Question 128: Alpha intrusion into NREM sleep (alpha-delta sleep) is associated with:

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

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 129: In brainstem auditory evoked potentials (BAEPs), Wave V is generated primarily by which structure?

Cochlear nucleus
Lateral lemniscus/inferior colliculus region (Correct answer)
Primary auditory cortex
Cochlear nerve (CN VIII)

Correct answer: Lateral lemniscus/inferior colliculus region

Wave V of the BAEP is generated at or near the lateral lemniscus and inferior colliculus, making it the most robust and clinically important wave.

Question 130: Latex allergy considerations in EEG primarily relate to:

Latex in electrode preparation materials such as gloves or elastic headbands used during the procedure (Correct answer)
The EEG machine housing
Electrode cables that contain latex
Paper used for printed reports

Correct answer: Latex in electrode preparation materials such as gloves or elastic headbands used during the procedure

Latex allergy precautions in EEG primarily involve gloves worn by the technologist and elastic headbands or chin straps used during the recording. Latex-free alternatives should be available for allergic patients.

Question 131: A technologist notices that channel 3 shows a 50% smaller deflection than all other channels during the calibration square wave. The most likely cause is:

A broken or high-impedance electrode on channel 3
A 60 Hz artifact contaminating channel 3
The notch filter being activated on channel 3
Gain set too low on the channel 3 amplifier (Correct answer)

Correct answer: Gain set too low on the channel 3 amplifier

When one channel shows a consistently smaller deflection than others during a known calibration signal, the amplifier gain for that channel is set too low.

Question 132: Which BAEP wave is generated by the auditory nerve (cranial nerve VIII) and is commonly absent in acoustic neuroma?

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

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 133: What is the recommended minimum distance between the photic stimulator and the patient's eyes during IPS?

10 cm
30 cm (Correct answer)
5 cm
1 meter

Correct answer: 30 cm

The photic stimulator is typically placed approximately 30 cm (about 12 inches) from the patient's eyes to ensure adequate luminance without discomfort or retinal risk.

Question 134: In a normal adult EEG, what is the expected effect of opening the eyes on the posterior alpha rhythm?

Alpha amplitude increases
Alpha spreads to frontal regions
Alpha is attenuated or blocked (Correct answer)
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 135: Rhythmic midtemporal theta of drowsiness (RMTD) is characterized by:

Continuous high-amplitude slow waves during deep sleep
Focal beta activity in the temporal region
Sharply contoured 5-7 Hz rhythmic theta bursts over the midtemporal regions during drowsiness, with a characteristic notched appearance (Correct answer)
Irregular polymorphic delta activity during wakefulness

Correct answer: Sharply contoured 5-7 Hz rhythmic theta bursts over the midtemporal regions during drowsiness, with a characteristic notched appearance

RMTD (formerly called psychomotor variant) consists of rhythmic, sharply contoured 5-7 Hz theta activity over one or both midtemporal regions during drowsiness, with a distinctive notched or flat-topped morphology.

Question 136: When measuring for electrode placement, the preauricular point is identified as:

The external auditory meatus
The tip of the ear lobe
The depression anterior to the tragus of the ear at the root of the zygoma (Correct answer)
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 137: Eye closure during photic stimulation testing serves what purpose?

It produces delta wave artifacts that mimic epileptiform activity
It enhances the photoparoxysmal response by removing fixation suppression (Correct answer)
It prevents retinal damage from the strobe light
It eliminates all photic driving responses

Correct answer: It enhances the photoparoxysmal response by removing fixation suppression

Eye closure removes fixation suppression, making it easier to elicit photoparoxysmal responses in susceptible individuals during IPS.

Question 138: In pediatric EEG, the posterior dominant rhythm (PDR) reaches its adult frequency of approximately 10 Hz by what age?

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

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 139: Stimulation of the median nerve in a somatosensory evoked potential (SSEP) study produces a cortical response designated N20 at approximately what latency in a normal adult?

30–35 ms
5–10 ms
18–21 ms (Correct answer)
12–15 ms

Correct answer: 18–21 ms

The N20 cortical potential following median nerve stimulation peaks at approximately 18–21 ms in normal adults, reflecting conduction time from wrist to primary somatosensory cortex.

Question 140: During a routine EEG, the standard display sensitivity is set to:

15 µV/mm
50 µV/mm
7 µV/mm (Correct answer)
3 µV/mm

Correct answer: 7 µV/mm

The standard display sensitivity for routine EEG is 7 µV/mm, which provides adequate visualization of normal brain rhythms. Sensitivity may be adjusted for high-amplitude (increase µV/mm) or low-amplitude (decrease µV/mm) activity.

Question 141: What montage is typically used as the initial display for reviewing a routine EEG?

Bipolar transverse montage
Bipolar longitudinal (double banana) montage (Correct answer)
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 142: What is the typical frequency range of theta activity in EEG?

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

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 143: What is the typical voltage (amplitude) range of normal alpha waves recorded from the scalp?

500–1000 µV
20–200 µV (Correct answer)
200–500 µV
5–10 µV

Correct answer: 20–200 µV

Alpha waves normally range from about 20 to 200 µV in amplitude when recorded from scalp electrodes.

Question 144: The wicket rhythm is a benign normal variant that can be confused with:

Occipital spikes
Sleep spindles
Temporal sharp waves or epileptiform discharges (Correct answer)
Frontal intermittent rhythmic delta activity

Correct answer: Temporal sharp waves or epileptiform discharges

Wicket spikes (or wicket rhythm) are arch-shaped 6-11 Hz waveforms over the temporal regions that can resemble temporal sharp waves, potentially leading to misdiagnosis of temporal lobe epilepsy if not recognized as benign.

Question 145: The posterior dominant rhythm (alpha rhythm) in a normal awake adult is generated primarily by which brain structure interaction?

Thalamocortical circuits involving the thalamus and occipital cortex (Correct answer)
Basal ganglia output to frontal cortex
Hippocampal-entorhinal connections
Brainstem reticular formation alone

Correct answer: Thalamocortical circuits involving the thalamus and occipital cortex

The alpha rhythm arises from synchronized oscillations in thalamocortical loops, with the thalamic relay nuclei (particularly the pulvinar and lateral geniculate) pacing cortical neurons in the occipital visual cortex.

Question 146: 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)
Rhythmic Mid-Temporal Theta of Drowsiness (RMTD)
Lambda Waves
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 147: 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)
A prolonged afterhyperpolarization and inhibitory postsynaptic potentials (IPSPs) (Correct answer)
Artifact from patient movement following the sharp wave
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 148: Which of the following flash frequencies used in intermittent photic stimulation (IPS) is most likely to elicit a photoparoxysmal response in photosensitive individuals?

3–5 Hz
15–20 Hz (Correct answer)
50 Hz
1–2 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 149: Generalized periodic discharges (GPDs) at 1-2 Hz intervals with triphasic morphology are most characteristic of which condition?

Juvenile myoclonic epilepsy
Lennox-Gastaut syndrome
Hepatic encephalopathy (Correct answer)
Benign rolandic epilepsy

Correct answer: Hepatic encephalopathy

Triphasic waves appearing as generalized periodic discharges are classically associated with metabolic encephalopathies, particularly hepatic encephalopathy, though they can be seen in other toxic-metabolic states.

Question 150: What is the minimum percentage of an epoch that must consist of delta waves for that epoch to be scored as stage N3 sleep?

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

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 151: During hyperventilation, if the patient has an underlying brain tumor, you would most likely expect to see:

Focal or lateralized slow-wave abnormality that increases in prominence (Correct answer)
Bilateral synchronous generalized slowing
High-frequency gamma activity over the tumor site
Suppression of all EEG activity

Correct answer: Focal or lateralized slow-wave abnormality that increases in prominence

Focal structural lesions such as tumors typically produce focal or lateralized slow-wave abnormalities that are accentuated by hyperventilation-induced hypocapnia.

Question 152: When setting up cEEG in the ICU, a reduced electrode array (e.g., 8–10 electrodes) is often used instead of full 10-20 because:

It is required by ACNS guidelines for all ICU recordings
It eliminates all artifact from ICU equipment
It provides higher spatial resolution than full arrays
It allows faster setup and is practical in critically ill patients while still detecting most seizures (Correct answer)

Correct answer: It allows faster setup and is practical in critically ill patients while still detecting most seizures

Reduced electrode sets are a practical compromise in ICU settings, enabling rapid application while still capturing the majority of electrographic seizures with acceptable sensitivity.

Question 153: Generalized background slowing with intermittent frontal rhythmic delta activity (FIRDA) in an adult typically indicates:

Focal frontal lobe epilepsy
Diffuse encephalopathy or deep midline dysfunction (Correct answer)
Posterior fossa tumor
Normal aging changes

Correct answer: Diffuse encephalopathy or deep midline dysfunction

FIRDA (now called generalized rhythmic delta activity with frontal predominance or GRDA) is a non-specific finding indicating diffuse cerebral dysfunction from metabolic, toxic, or structural causes affecting deep midline structures.

Question 154: The Delta wave frequency is

Under 4 Hertz (Correct answer)
Over 13 Hertz
8–13 Hertz
4–7 Hertz

Correct answer: Under 4 Hertz

Brainwaves known as delta waves are connected to unconsciousness and profound sleep. They occur less frequently than four times per second because their frequency range is less than four Hertz. The slowest and largest amplitude brainwaves fall within this frequency range. It's crucial to remember that delta waves are more frequently seen in newborns and early children and are normally only seen in adults during deep sleep or in specific brain illnesses.

Question 155: Approximately how many stimulus repetitions (averages) are typically needed to obtain a reliable, reproducible BAEP waveform?

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

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 156: What is the standard calibration signal used to verify EEG amplifier function?

A 50 µV square wave at 1 Hz (Correct answer)
A 100 µV triangle wave at 5 Hz
A 200 µV sine wave at 60 Hz
A 10 µV sine wave at 10 Hz

Correct answer: A 50 µV square wave at 1 Hz

The standard calibration signal is a 50 µV square wave at 1 Hz. This verifies amplifier gain accuracy, frequency response, and channel matching across the system.

Question 157: Slow, sinusoidal, high-amplitude waves that wax and wane over frontal electrodes in a drowsy, diaphoretic patient are most characteristic of:

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

Correct answer: Sweat artifact

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

Question 158: 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
EKG artifact
Sweat 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 159: The Laplacian (source derivation) montage differs from standard montages by:

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

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

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

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

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

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 162: 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:

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

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 163: 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 164: Delta activity (0.5-4 Hz) in a normal awake adult EEG is considered abnormal because it typically indicates:

Increased alpha variant activity
Normal arousal response
Enhanced attention and concentration
Cortical dysfunction from structural or metabolic causes (Correct answer)

Correct answer: Cortical dysfunction from structural or metabolic causes

In awake adults, delta activity is abnormal and suggests cortical or subcortical dysfunction. Focal delta suggests structural lesion; generalized delta suggests diffuse encephalopathy or deep midline dysfunction.

Question 165: Which cortical layer contains the large pyramidal neurons (Betz cells) that give rise to corticospinal tract fibers?

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

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 166: Positive Occipital Sharp Transients of Sleep (POSTS) and Lambda waves are two non-epileptiform patterns that share a similar morphology and occipital location. What is the primary distinguishing feature between them?

The polarity of the sharp component.
The frequency of the transients.
The patient's state of consciousness. (Correct answer)
The symmetry of the waveforms.

Correct answer: The patient's state of consciousness.

The key factor that differentiates POSTS from Lambda waves is the patient's state. Lambda waves occur exclusively during the awake state when the patient's eyes are open and they are visually scanning their environment. [38, 40] In contrast, POSTS are a hallmark of drowsiness and light sleep (N1/N2) and disappear when the patient is awake. [28, 30, 32]

Question 167: In a longitudinal bipolar montage, often called a 'double banana', how are the electrodes connected?

In chains running from the left to the right side of the head.
In chains running from anterior to posterior regions of the head. (Correct answer)
To a single common reference electrode, such as the vertex (Cz).
Each electrode is compared to a weighted average of its surrounding electrodes.

Correct answer: In chains running from anterior to posterior regions of the head.

The longitudinal bipolar montage, or 'double banana', consists of chains of electrodes linked from front to back. For example, a temporal chain might connect Fp1-F7, F7-T3, T3-T5, and T5-O1. This arrangement is excellent for identifying phase reversals, which help localize the source of an abnormality between two adjacent electrodes.

Question 168: Which evoked potential modality is most useful for monitoring spinal cord function during scoliosis correction surgery?

Somatosensory evoked potentials (Correct answer)
Brainstem auditory evoked potentials
Visual evoked potentials
P300 event-related 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 169: What precaution should be taken when performing EEG on a patient with a suspected skull fracture or recent craniotomy?

Only use subdermal needle electrodes at the affected site
No special precautions are needed — standard application applies
Avoid placing electrodes over or applying pressure to the affected area, and consult with the clinical team (Correct answer)
EEG is absolutely contraindicated in these patients

Correct answer: Avoid placing electrodes over or applying pressure to the affected area, and consult with the clinical team

Electrode application over skull fractures or recent craniotomy sites requires avoiding direct pressure on the area, using alternative electrode positions, and coordinating with the clinical team to prevent complications.

Question 170: Electrocerebral silence (ECS) on EEG, required for brain death determination, must be recorded at a sensitivity of:

10 µV/mm for 60 minutes
2 µV/mm for 30 minutes with inter-electrode distances ≥10 cm (Correct answer)
1 µV/mm for 10 minutes
5 µV/mm for 15 minutes

Correct answer: 2 µV/mm for 30 minutes with inter-electrode distances ≥10 cm

ACNS guidelines for EEG confirmation of brain death require recording at ≥2 µV/mm sensitivity for at least 30 minutes, using electrodes ≥10 cm apart, with no reactivity.

Question 171: Signal averaging in evoked potential recording improves waveform clarity primarily because:

It eliminates biological noise by randomizing it across trials
The evoked response is time-locked to the stimulus while background EEG cancels out with repeated averaging (Correct answer)
It increases the stimulation frequency proportional to the number of averages
It amplifies the stimulus artifact to improve timing reference

Correct answer: The evoked response is time-locked to the stimulus while background EEG cancels out with repeated averaging

The neural response to each stimulus occurs at a fixed latency (time-locked), so it adds coherently across averages; random background EEG noise is uncorrelated and averages toward zero, improving signal-to-noise ratio.

Question 172: The 14-and-6 Hz positive spikes pattern is considered:

A highly pathological pattern requiring immediate treatment
An indicator of deep midline structural lesion
A benign normal variant seen in adolescents during drowsiness and light sleep (Correct answer)
A pattern seen exclusively in neonates

Correct answer: A benign normal variant seen in adolescents during drowsiness and light sleep

14-and-6 Hz positive spikes (also called positive bursts or ctenoids) are a benign normal variant most commonly seen in adolescents during drowsiness and light sleep, predominantly over posterior temporal regions.

Question 173: In normal neonatal EEGs, which activity pattern is considered developmentally appropriate but would be abnormal in a healthy adult?

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

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 174: What is the primary safety concern when performing EEG on a patient in the ICU with external ventricular drains?

Risk of infection or displacement of the drain during electrode application (Correct answer)
Need for sedation during the recording
Interference from the drain's electrical signal
Risk of photic-induced seizures

Correct answer: Risk of infection or displacement of the drain during electrode application

Electrode application near external ventricular drains (EVDs) poses risks of infection (introducing pathogens near the surgical site) and mechanical displacement of the drain. Careful coordination with nursing and neurosurgery is essential.

Question 175: What is the upper limit of normal for the interpeak latency I–V (IPL I–V) in BAEPs recorded from a typical adult?

Less than 2.0 ms
Less than 4.4 ms (Correct answer)
Less than 6.0 ms
Less than 3.0 ms

Correct answer: Less than 4.4 ms

The IPL I–V, representing total brainstem conduction time, normally does not exceed approximately 4.4 ms; values beyond this suggest central conduction slowing.

Question 176: AAN guidelines recommend that ECI be recorded for a minimum duration of how many minutes of technically satisfactory tracing?

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

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 177: An EEG technologist notes that a patient's EEG shows generalized high-amplitude rhythmic delta with superimposed faster frequencies. The patient's chart indicates a blood glucose of 28 mg/dL. The MOST likely explanation for this EEG pattern is:

Hypoglycemic encephalopathy producing diffuse metabolic slowing (Correct answer)
Subcortical ischemia from a posterior circulation stroke
Benzodiazepine overdose
Nonconvulsive status epilepticus

Correct answer: Hypoglycemic encephalopathy producing diffuse metabolic slowing

Severe hypoglycemia deprives neurons of their primary energy substrate, producing diffuse encephalopathy with EEG slowing ranging from theta to delta frequencies, often with high amplitude. This metabolic encephalopathy reverses rapidly with glucose correction. The clinical context (blood glucose 28 mg/dL) makes this the most parsimonious explanation.

Question 178: Burst suppression on EEG in a critically ill patient is characterized by:

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

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

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

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 180: Hypnagogic hypersynchrony in children refers to:

High-amplitude 3–4.5 Hz rhythmic activity at drowsiness onset (Correct answer)
K-complexes occurring in clusters
Sleep spindles exceeding 15 Hz
Delta bursts during REM

Correct answer: High-amplitude 3–4.5 Hz rhythmic activity at drowsiness onset

Hypnagogic hypersynchrony is a normal pediatric variant of high-amplitude slow rhythmic activity seen during drowsiness that should not be mistaken for a seizure.

Question 181: What guidance should patients receive about bathing and water exposure during an ambulatory EEG recording?

Water exposure has no effect on ambulatory EEG recordings
Brief hot showers are encouraged to improve electrode contact
Normal bathing and swimming are permitted
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 182: During intraoperative monitoring with somatosensory evoked potentials, which change should prompt immediate surgical notification?

50% amplitude decrease or 10% latency increase (Correct answer)
10% amplitude decrease
Baseline drift only
Any waveform variability

Correct answer: 50% amplitude decrease or 10% latency increase

The universally accepted alarm criterion for intraoperative SSEP is a ≥50% amplitude decrease or ≥10% latency increase from baseline.

Question 183: The cortical area represented by electrode T3 (T7 in modified nomenclature) overlies which brain region?

Right parietal lobe
Superior frontal gyrus
Occipital pole
Left mid-temporal region near the Sylvian fissure (Correct answer)

Correct answer: Left mid-temporal region near the Sylvian fissure

T3 (T7) is positioned over the left mid-temporal region, approximately overlying the middle temporal gyrus near the lateral sulcus (Sylvian fissure), a common area for temporal lobe epilepsy discharges.

Question 184: Cajal-Retzius cells in cortical layer I release reelin, which guides neuronal migration. Dysfunction in this process can result in lissencephaly, which characteristically produces what EEG pattern?

Very high voltage slow activity with multifocal spikes (Correct answer)
High-amplitude fast activity (>14 Hz) diffusely
Persistent alpha coma pattern
Normal background with occasional spikes

Correct answer: Very high voltage slow activity with multifocal spikes

Lissencephaly produces disorganized cortical architecture with very high-voltage slow waves and multifocal epileptiform discharges due to abnormal cortical lamination.

Question 185: FIRDA (Frontal Intermittent Rhythmic Delta Activity) is most commonly associated with which condition?

Diffuse encephalopathy or deep midline dysfunction (Correct answer)
Normal variant in elderly
Focal cortical lesion
Temporal lobe epilepsy

Correct answer: Diffuse encephalopathy or deep midline dysfunction

FIRDA reflects diffuse cerebral dysfunction or deep midline/diencephalic disturbance and is not a focal or epileptiform finding.

Question 186: Analog-to-digital conversion in digital EEG requires an anti-aliasing filter because:

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

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

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

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 188: During an EEG on a febrile and diaphoretic patient, the technologist observes very slow, undulating, low-frequency (<0.5 Hz) waves that are widespread and cause the baselines of multiple channels to sway. This pattern is most characteristic of which type of artifact?

Respiration artifact
Glossokinetic artifact
Pulse artifact
Sweat artifact (Correct answer)

Correct answer: Sweat artifact

Sweat (perspiration) changes the electrical properties and conductivity at the skin-electrode interface. This change in impedance creates very slow, rolling baseline sway, also known as galvanic skin response (GSR), which is consistent with the described pattern.

Question 189: In pediatric EEG, the hyperventilation response in children differs from adults in that:

Children develop beta activity instead of slowing
The response is identical to adults at all ages
Children show no response to hyperventilation
Children typically show a more prominent and prolonged buildup response with higher amplitude slowing (Correct answer)

Correct answer: Children typically show a more prominent and prolonged buildup response with higher amplitude slowing

Children demonstrate a more robust hyperventilation buildup response than adults, with more prominent high-amplitude generalized slowing that may persist longer after cessation. This is normal and should not be mistaken for pathology.

Question 190: Which ascending arousal pathway originating in the locus coeruleus modulates cortical excitability and EEG background through norepinephrine release?

Dorsal noradrenergic bundle (Correct answer)
Raphe-cortical serotonin pathway
Mesolimbic dopamine pathway
Nigrostriatal 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 191: In digital EEG systems, the Nyquist theorem states that to accurately digitize a signal, the sampling rate must be at least:

Twice the highest frequency of interest (Correct answer)
Ten times the highest frequency of interest
1.5 times the highest frequency of interest
Equal to the highest frequency of interest

Correct answer: Twice the highest frequency of interest

The Nyquist theorem requires a sampling rate of at least twice the highest frequency component to avoid aliasing artifacts in the digitized signal.

Question 192: For a patient who cannot perform volitional hyperventilation (e.g., young child), an alternative activation method may include:

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

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 193: 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)
Its focal and asymmetric nature.
The presence of intermixed beta frequencies.
The high amplitude of the activity compared to the contralateral side.

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 194: An EEG showing continuous generalized polymorphic delta slowing with no clear faster frequencies in a patient with altered consciousness most likely indicates what?

Normal drowsiness pattern
REM sleep
Severe diffuse cortical dysfunction (Correct answer)
Stage 3 NREM sleep

Correct answer: Severe diffuse cortical dysfunction

Continuous generalized polymorphic delta without faster activity in a wakeful patient indicates severe diffuse encephalopathy affecting cortical function.

Question 195: A rhythmic artifact at exactly 60 Hz appearing uniformly across all electrodes is most consistent with:

Electrode pop
Cardiac artifact
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 196: A technologist notices a patient's pacemaker is not listed on the referral but the patient mentions it during setup. Which is the correct immediate action regarding electrical safety?

Proceed since modern EEG machines produce no significant current that could affect pacemakers
Replace all electrodes with wireless Bluetooth electrodes to eliminate any risk
Complete the study but avoid placing electrodes near the chest
Stop setup, verify pacemaker type and settings with the patient's cardiologist, and document the finding before proceeding (Correct answer)

Correct answer: Stop setup, verify pacemaker type and settings with the patient's cardiologist, and document the finding before proceeding

Undisclosed implanted devices require clinical verification before proceeding because certain electrode currents and stimulation protocols may interact with pacemaker function.

Question 197: Breach rhythm is a normal consequence of a skull defect that appears as:

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

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

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

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 199: 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)
Bursts are consistently asymmetric between hemispheres
Delta activity is absent during burst periods

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 200: Which EEG pattern is characterized by diffuse slowing that waxes and wanes and is classically associated with hepatic encephalopathy?

FIRDA
Triphasic waves (Correct answer)
Burst suppression
Beta spindles

Correct answer: Triphasic waves

Triphasic waves are bilaterally synchronous, frontally dominant, high-amplitude slow waves classically seen in hepatic encephalopathy and other toxic-metabolic states.

Question 201: The standard paper speed used in routine clinical EEG recording in the United States is:

30 mm/sec (Correct answer)
10 mm/sec
60 mm/sec
15 mm/sec

Correct answer: 30 mm/sec

30 mm/sec is the standard paper speed for routine clinical EEG in the US, providing optimal visualization of typical brain wave frequencies.

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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