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

Question 1: What distinguishes a polyspike-and-wave complex from a single spike-and-wave complex?

Polyspike-and-wave has a slower frequency than single spike-and-wave
Polyspike-and-wave contains multiple spikes (2 or more) preceding the slow wave component (Correct answer)
Polyspike-and-wave occurs only during REM sleep
Polyspike-and-wave is always focal rather than generalized

Correct answer: Polyspike-and-wave contains multiple spikes (2 or more) preceding the slow wave component

Polyspike-and-wave complexes contain a burst of two or more spikes before the slow wave, and are particularly associated with juvenile myoclonic epilepsy and other generalized epilepsies with myoclonic seizures.

Question 2: A technologist changes the sensitivity setting from 7 µV/mm to 10 µV/mm. How will this affect the appearance of a 70 µV spike on the display?

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

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

Monophasic
Transient
Polyphasic
Triphasic (Correct answer)

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

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

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 5: The alpha rhythm in a normal awake adult typically has a frequency range of:

0.5–3 Hz
4–7 Hz
8–13 Hz (Correct answer)
14–30 Hz

Correct answer: 8–13 Hz

The normal adult alpha rhythm ranges from 8 to 13 Hz and is best seen over posterior regions with eyes closed.

Question 6: Amplitude-integrated EEG (aEEG) is most commonly used in which clinical setting?

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

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

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

Question 7: In pediatric EEG, the hyperventilation response in children differs from adults in that:

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

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

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

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 9: In the ACNS ICU EEG terminology, the '+F' modifier on a periodic discharge pattern indicates:

Superimposed fast activity on the discharge (Correct answer)
Fixed morphology unchanged over time
Associated frequency >4 Hz
Focal predominance of the pattern

Correct answer: Superimposed fast activity on the discharge

The '+F' modifier in ACNS standardized terminology denotes the presence of superimposed fast (beta-range) activity riding on top of the periodic or rhythmic discharge.

Question 10: The lateral sulcus (Sylvian fissure) separates the frontal and parietal lobes above from which lobe below?

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

Correct answer: Temporal lobe

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

Question 11: What is the primary waveform of clinical interest in a pattern reversal visual evoked potential (VEP)?

P200
P100 (Correct answer)
N145
N75

Correct answer: P100

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

Question 12: During an ambulatory EEG, a patient calls to report they removed the electrodes themselves because of discomfort. What is the technologist's primary ethical obligation?

Respect patient autonomy, document the removal, and notify the ordering physician (Correct answer)
Report the patient to the billing department for equipment misuse
Document the incident and attempt to retrieve the equipment
Immediately dispatch a technologist to reapply electrodes without discussing with the patient

Correct answer: Respect patient autonomy, document the removal, and notify the ordering physician

Patients have the right to discontinue testing; the technologist must respect autonomy, document thoroughly, and inform the physician.

Question 13: 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:

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

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 14: Electrographic seizure activity on EEG is defined by which characteristic evolution?

Random isolated spikes without pattern
Only generalized tonic-clonic movements on video
Evolving pattern with change in frequency, morphology, or spatial distribution over time (Correct answer)
Static, unchanging repetitive discharges

Correct answer: Evolving pattern with change in frequency, morphology, or spatial distribution over time

Electrographic seizures are defined by evolution — a progressive change in frequency, amplitude, morphology, and/or spatial distribution over at least 10 seconds, distinguishing them from brief interictal discharges.

Question 15: A technologist uses a short-time constant (high-pass filter increase) to reduce which type of artifact?

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

Correct answer: Slow sweat artifact

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

Question 16: K-complexes are characterized by which of the following features?

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

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

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

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 18: Rhythmic midtemporal theta of drowsiness (RMTD) is characterized by:

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
Focal beta activity in the temporal region
Continuous high-amplitude slow waves during deep sleep

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

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

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

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

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

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

Question 21: Which of the following describes the typical, normal response to hyperventilation in a healthy 8-year-old child's EEG?

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

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

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

Question 22: What is the typical voltage (amplitude) range of normal alpha waves recorded from the scalp?

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

Correct answer: 20–200 µV

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

Question 23: What does a referential montage compare each electrode to?

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

Correct answer: A common reference electrode

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

Question 24: Reflex epilepsy triggered by specific cognitive tasks (such as reading or calculating) is an example of:

Normal hyperventilation response
Medication-induced seizures
Cognitive activation of seizures (thinking epilepsy or praxis-induced epilepsy) (Correct answer)
Photosensitive epilepsy

Correct answer: Cognitive activation of seizures (thinking epilepsy or praxis-induced epilepsy)

Praxis-induced or cognitive-task-induced epilepsy is a form of reflex epilepsy where specific mental activities (reading, calculating, spatial tasks) trigger epileptiform discharges or seizures, most commonly in genetic generalized epilepsies.

Question 25: In terms of cortical dipole orientation, activity generated on the crown of a gyrus produces:

A tangential dipole that is difficult to detect on scalp EEG
A quadrupolar field pattern
A radial dipole oriented perpendicular to the scalp surface, most easily detected by nearby scalp electrodes (Correct answer)
No detectable signal at any scalp electrode

Correct answer: A radial dipole oriented perpendicular to the scalp surface, most easily detected by nearby scalp electrodes

Cortical activity on the gyral crown creates a radial dipole (perpendicular to the scalp surface), which is optimally oriented for detection by overlying scalp electrodes, unlike sulcal activity which creates tangential dipoles.

Question 26: In a bipolar longitudinal montage, what is the typical chain order for the left hemisphere?

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

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

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

Question 27: What is the purpose of the ground electrode in an EEG recording?

To serve as the primary reference
To measure impedance across the scalp
To detect eye movement artifacts
To reduce common-mode noise and electrical interference (Correct answer)

Correct answer: To reduce common-mode noise and electrical interference

The ground electrode helps the amplifier reject common-mode noise and electrical interference by providing a reference point for the differential amplifier.

Question 28: Breach rhythm is a normal consequence of a skull defect that appears as:

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

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 29: Dynamic range in digital EEG refers to:

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

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

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

Question 30: What is the primary purpose of the 'biological calibration' signal used in EEG systems?

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

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

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

Question 31: 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?

5–10 ms
30–35 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 32: Periodic lateralized epileptiform discharges (PLEDs) are most commonly associated with which condition?

Metabolic encephalopathy
Acute structural brain lesion such as stroke (Correct answer)
Benign childhood epilepsy
Normal drowsiness

Correct answer: Acute structural brain lesion such as stroke

PLEDs (now called lateralized periodic discharges or LPDs) are strongly associated with acute destructive brain lesions, most commonly stroke, and may indicate ongoing seizure activity.

Question 33: Which of the following EEG findings is most characteristic of a patient performing lateral eye movements to the right?

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

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

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

Question 34: In a normal adult EEG, what is the expected effect of opening the eyes on the posterior alpha rhythm?

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

Correct answer: Alpha is attenuated or blocked

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

Question 35: Which patient condition is an absolute contraindication to photic stimulation during EEG?

History of photosensitive epilepsy with prior status epilepticus (Correct answer)
Anxiety disorder
Mild hypertension
Drowsiness

Correct answer: History of photosensitive epilepsy with prior status epilepticus

History of photosensitive epilepsy with prior status epilepticus is an absolute contraindication because photic stimulation could trigger a prolonged seizure.

Question 36: An EEG showing continuous generalized polymorphic delta slowing with no clear faster frequencies in a patient with altered consciousness most likely indicates what?

REM sleep
Normal drowsiness pattern
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 37: The time constant of an EEG amplifier determines:

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

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

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

Question 38: 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?

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

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

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

Correct answer: Chewing/jaw muscle artifact

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

Question 40: What infection control measure is required when applying reusable EEG electrodes between patients?

Electrodes must be disinfected or sterilized according to facility protocol between each patient (Correct answer)
Rinsing electrodes with tap water is sufficient
Alcohol wipe of the electrode surface is the only requirement
Electrodes only need cleaning if visible contamination is present

Correct answer: Electrodes must be disinfected or sterilized according to facility protocol between each patient

Reusable EEG electrodes must undergo proper disinfection or sterilization between patients to prevent transmission of infections, following facility-specific protocols and manufacturer guidelines.

Question 41: During hyperventilation activation in EEG, what is the expected normal response in an adult?

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

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 42: Which montage type displays the voltage difference between each electrode and a common reference point?

Bipolar longitudinal montage
Bipolar transverse montage
Referential montage (Correct answer)
Laplacian montage

Correct answer: Referential montage

A referential montage shows the potential at each electrode compared to a single common reference (such as linked ears, Cz, or an average reference), allowing direct comparison of amplitudes across channels.

Question 43: Sleep efficiency is calculated as:

Total sleep time divided by time in bed × 100 (Correct answer)
REM time divided by total sleep time × 100
Sleep onset latency divided by time in bed × 100
Total sleep time divided by total recording time × 100

Correct answer: Total sleep time divided by time in bed × 100

Sleep efficiency = (TST / TIB) × 100; a value ≥85% is generally considered normal in adults.

Question 44: The primary physiological mechanism by which hyperventilation (HV) activates epileptiform discharges is through inducing:

Increased cerebral blood flow and oxygenation.
Respiratory alkalosis and cerebral vasoconstriction. (Correct answer)
Respiratory acidosis and cerebral vasodilation.
A decrease in heart rate and systemic blood pressure.

Correct answer: Respiratory alkalosis and cerebral vasoconstriction.

Hyperventilation causes a rapid decrease in arterial CO2 (hypocapnia), leading to respiratory alkalosis. The brain compensates for this change in blood pH by constricting cerebral blood vessels, which reduces cerebral blood flow and can lead to mild cerebral hypoxia, thereby lowering the seizure threshold in susceptible individuals.

Question 45: A flatline EEG tracing recorded at 2 µV/mm sensitivity is most likely artifactual rather than true ECI if which finding is present?

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

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 46: Generalized voltage attenuation (low-voltage EEG) with amplitudes below 20 µV throughout may be caused by:

Scalp edema, subdural fluid, or certain medications such as barbiturates (Correct answer)
Caffeine ingestion in the last hour
Hyperventilation artifact
Photic driving response

Correct answer: Scalp edema, subdural fluid, or certain medications such as barbiturates

Generalized low voltage can result from physical barriers between brain and electrodes (scalp edema, subdural effusions, thick skull) or from cortical suppression by medications like barbiturates, hypothermia, or severe diffuse brain injury.

Question 47: The primary generators of the electrical potentials recorded by scalp EEG are:

Axonal currents from white matter tracts
Action potentials from deep cortical neurons
Postsynaptic potentials of pyramidal cells in the cerebral cortex (Correct answer)
Electrical activity from glial cells and astrocytes

Correct answer: Postsynaptic potentials of pyramidal cells in the cerebral cortex

Scalp EEG primarily reflects the summation of excitatory (EPSPs) and inhibitory (IPSPs) postsynaptic potentials from large, vertically oriented pyramidal neurons in the cerebral cortex. Action potentials are too brief and their electrical fields are too localized to be reliably detected at the scalp. Glial cells and white matter tracts do not generate the synchronized electrical fields necessary for scalp EEG detection.

Question 48: Which montage change is most useful for confirming that a suspected artifact is truly artifactual rather than cerebral?

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

Correct answer: Switching between bipolar and referential montages

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

Question 49: Which EEG frequency band is most prominent during deep NREM sleep (stage N3)?

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

Correct answer: Delta (0.5–4 Hz)

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

Question 50: A technologist is reviewing an EEG on a digital system and wants to enhance the visualization of a very localized, focal discharge while minimizing the influence from distant, widespread activity. Which montage would be the most appropriate choice?

Longitudinal bipolar montage
Average reference montage
Laplacian montage (Correct answer)
Contralateral ear reference montage

Correct answer: Laplacian montage

The Laplacian montage, also known as a source derivation or local average reference, is specifically designed to highlight focal activity. It calculates the voltage at each electrode relative to a weighted average of its immediate surrounding electrodes. This technique enhances localized events and reduces the effect of widespread or distant electrical fields.

Question 51: Glossokinetic artifact is caused by movement of which structure?

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

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

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

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 53: What documentation should the EEG technologist include in the technical report for a routine study?

Only the start and end time of the recording
A diagnosis based on the EEG findings
Just the montages used during the recording
Patient state, medications, impedance values, activation procedure details, artifacts encountered, and any clinical events observed (Correct answer)

Correct answer: Patient state, medications, impedance values, activation procedure details, artifacts encountered, and any clinical events observed

The technical report should comprehensively document patient state, current medications, electrode impedances, activation procedures performed and their responses, artifacts encountered, clinical observations, and any events during the recording.

Question 54: Sweat artifact on EEG typically presents as:

Rhythmic 14 Hz activity at temporal electrodes
High-frequency beta activity over central regions
Very slow, undulating baseline shifts in the delta or sub-delta frequency range (Correct answer)
Sharp spike-like transients at all electrodes simultaneously

Correct answer: Very slow, undulating baseline shifts in the delta or sub-delta frequency range

Sweat artifact produces slow, rolling baseline undulations (typically <1 Hz) caused by changes in skin potential and electrode impedance from perspiration, often appearing as very slow waves that can obscure underlying EEG activity.

Question 55: Which EEG feature is the hallmark of Stage N2 sleep?

Delta waves >75 µV
Alpha rhythm dropout
Sawtooth waves
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 56: Theta waves' frequency is

8–13 Hertz
More than thirteen hertz
less than four Hz
4–7 Hertz (Correct answer)

Correct answer: 4–7 Hertz

Brainwaves known as theta waves can happen during deep relaxation or light sleep. They oscillate at a rate of 4 to 7 cycles per second, with a frequency range of 4-7 Hertz. Deep concentration, improved memory, and increased creativity are all linked to this frequency range. Deep sleep is usually associated with frequencies below 4 Hertz, while wakefulness and relaxation are related with frequencies above 7 Hertz, which are connected with alpha waves. Therefore, 4–7 Hertz is the right response.

Question 57: Which EEG pattern during absence status epilepticus distinguishes it from typical 3-Hz absence discharges?

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

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

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

Question 58: When applying EEG electrodes using collodion, what substance is used to remove them after the recording?

Acetone (Correct answer)
Electrode gel
Saline solution
Isopropyl alcohol

Correct answer: Acetone

Acetone is used to dissolve collodion and safely remove electrodes from the scalp after the EEG recording.

Question 59: Sleep onset REM (SOREMP) within 15 minutes of sleep onset on a PSG is most suggestive of:

Narcolepsy (Correct answer)
Idiopathic hypersomnia
Restless legs syndrome
Obstructive sleep apnea

Correct answer: Narcolepsy

SOREMPs are a key diagnostic finding in narcolepsy, where the loss of orexin/hypocretin neurons disrupts normal sleep architecture and causes premature REM onset.

Question 60: On a qEEG trend panel, a sudden increase in the seizure probability (SP) line coincides with a visible change on the rhythmic run detector. The NEXT step for the EEG technologist should be:

Increase the high-frequency filter setting to reduce muscle artifact
Review the corresponding raw EEG segment to confirm whether the trend reflects a true electrographic seizure or artifact (Correct answer)
Immediately notify the physician that the patient is in status epilepticus
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 61: 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 62: Which activation procedure is most effective for provoking absence seizures during a routine EEG?

Sleep deprivation
Hyperventilation (Correct answer)
Intermittent photic stimulation
Cold water caloric testing

Correct answer: Hyperventilation

Hyperventilation is the most effective provocative maneuver for absence seizures, eliciting 3 Hz spike-and-wave discharges in approximately 80-90% of patients with untreated typical absence epilepsy.

Question 63: According to the American Clinical Neurophysiology Society (ACNS) guidelines, interelectrode impedances should be within what range for a standard EEG recording?

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

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

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

Question 64: During the transition from wakefulness to drowsiness, the expected EEG changes include:

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

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

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

Question 65: A continuous EEG shows lateralized periodic discharges (LPDs) at 2 Hz in a patient with herpes simplex encephalitis. What is the significance of LPDs in this context?

They confirm the diagnosis of HSV encephalitis
They indicate ictal or interictal activity and require antiseizure consideration (Correct answer)
They are pathognomonic for focal cortical dysplasia
They represent a benign artifact from electrode impedance mismatch

Correct answer: They indicate ictal or interictal activity and require antiseizure consideration

LPDs in HSV encephalitis represent a continuum between interictal and ictal activity (the 'ictal-interictal continuum') and typically warrant antiseizure medication evaluation.

Question 66: What is the primary clinical advantage of flash VEPs over pattern reversal VEPs?

Shorter recording time due to lower averaging requirement
Can be performed in uncooperative or visually impaired patients unable to fixate on a pattern (Correct answer)
Better amplitude resolution of cortical responses
Greater sensitivity for demyelinating optic nerve disease

Correct answer: Can be performed in uncooperative or visually impaired patients unable to fixate on a pattern

Flash VEPs require only light perception and no fixation, making them useful in infants, comatose patients, or those with dense media opacities, even though pattern reversal VEPs are more diagnostically sensitive.

Question 67: An EEG shows electrical status epilepticus during slow-wave sleep (ESES), with spike-wave index exceeding 85%. This pattern underlies which syndrome?

Ohtahara syndrome
Childhood absence epilepsy
Lennox-Gastaut syndrome
Continuous spike-waves during slow sleep (CSWS) / Landau-Kleffner syndrome spectrum (Correct answer)

Correct answer: Continuous spike-waves during slow sleep (CSWS) / Landau-Kleffner syndrome spectrum

ESES (spike-wave index > 85% during NREM sleep) is the electrographic hallmark of CSWS and Landau-Kleffner syndrome, associated with acquired cognitive or language regression.

Question 68: 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:

Cardiac artifact
Ventilator artifact (Correct answer)
Movement 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 69: Sleep spindles are a hallmark of which stage of sleep?

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

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

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

Correct answer: Focal polymorphic delta slowing

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

Question 71: In polysomnography scoring, an arousal is defined as an abrupt EEG frequency shift lasting at least:

10 seconds
3 seconds (Correct answer)
15 seconds
1 second

Correct answer: 3 seconds

AASM defines an arousal as an abrupt shift to higher EEG frequencies (alpha, theta, or >16 Hz) lasting ≥3 seconds, preceded by ≥10 seconds of sleep.

Question 72: Which normal EEG variant appearing at sleep onset consists of brief 4–6 Hz runs with a positive polarity at the vertex?

6 Hz spike-and-wave (phantom spike)
Wicket spikes
POSTS
Hypnic jerks with associated vertex potentials (Correct answer)

Correct answer: Hypnic jerks with associated vertex potentials

Hypnic jerks are sudden body twitches at sleep onset that correlate with brief vertex-maximal EEG potentials and are a normal physiologic phenomenon.

Question 73: In the 10-20 system, which electrode is located at the vertex of the skull?

C3
Pz
Fz
Cz (Correct answer)

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

Cardiac artifact
AC line noise (Correct answer)
Electrode pop
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 75: When performing a square wave calibration, the 'tilt' or slant on the flat top of the square wave most likely indicates a problem with:

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

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

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

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

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

Question 77: What is the normal frequency range of the posterior dominant rhythm (alpha rhythm) in a healthy awake adult?

8-13 Hz (Correct answer)
4-7 Hz
14-20 Hz
21-30 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 78: Photomyogenic (photomyoclonic) response, which can mimic a photoparoxysmal response, differs in that it:

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

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

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

Question 79: The blood-brain barrier's role in EEG is primarily related to:

Filtering EEG signals before they reach the scalp
Directly generating electrical potentials recorded on 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 80: Which neonatal EEG pattern is considered highly abnormal and suggests severe encephalopathy?

Tracé alternant
Delta brushes in the temporal regions
Burst-suppression with interburst intervals showing isoelectric or near-isoelectric activity (Correct answer)
Activité moyenne (continuous medium-voltage mixed pattern)

Correct answer: Burst-suppression with interburst intervals showing isoelectric or near-isoelectric activity

Burst-suppression is a severely abnormal neonatal EEG pattern with bursts of high-voltage mixed activity separated by nearly isoelectric periods, indicating severe diffuse cerebral dysfunction from hypoxic-ischemic injury, metabolic disorders, or other causes.

Question 81: In a healthy, awake adult, the presence of excessive, generalized, and persistent theta activity (4-7 Hz) would most likely be interpreted as:

A normal posterior dominant rhythm.
An indicator of deep relaxation.
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 82: 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
10-12 Hz
8-9 Hz (Correct answer)

Correct answer: 8-9 Hz

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

Question 83: Which epileptiform feature specifically distinguishes a true spike from a sharp wave on EEG?

Amplitude greater than 200 µV
Occurrence only during NREM sleep
Duration less than 70 ms vs. 70–200 ms (Correct answer)
Presence of a following slow wave

Correct answer: Duration less than 70 ms vs. 70–200 ms

By convention, a spike has a duration of less than 70 ms, whereas a sharp wave has a duration of 70–200 ms; both may be followed by a slow wave.

Question 84: 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 85: What electrical safety measure prevents harmful current flow through the patient during EEG recording?

Using only metal electrodes instead of plastic
Electrical isolation of the patient circuit from ground through optically coupled or transformer-isolated amplifier inputs (Correct answer)
Connecting all electrodes directly to the building ground
Using maximum amplifier gain at all times

Correct answer: Electrical isolation of the patient circuit from ground through optically coupled or transformer-isolated amplifier inputs

Modern EEG amplifiers use electrical isolation (optical coupling or transformer isolation) between the patient-connected inputs and the mains-powered electronics, preventing dangerous ground currents from flowing through the patient.

Question 86: In juvenile myoclonic epilepsy (JME), the EEG hallmark is polyspike-and-wave discharges typically at which frequency?

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

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 87: At what age does the posterior dominant rhythm typically reach the adult alpha frequency range of 8 Hz?

6 months
3 years (Correct answer)
1 year
8 years

Correct answer: 3 years

The posterior dominant rhythm gradually increases from approximately 3-4 Hz in infancy to 8 Hz by around age 3 years, continuing to increase to the full adult range of 8-13 Hz by approximately age 8-10 years.

Question 88: What percentage of total sleep time must be occupied by high-amplitude delta activity to score Stage N3?

30% or more (Correct answer)
10%
50%
20%

Correct answer: 30% or more

AASM scoring criteria require that delta waves (0.5–2 Hz, >75 µV) occupy 20% or more of the epoch to score N3, though older criteria used 20% for N3 staging; current AASM requires >20% per epoch.

Question 89: During hyperventilation in a normal adult, what EEG change is expected?

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

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 90: In a bipolar transverse montage, the electrode chains run in which direction?

Left to right across the head (coronal) (Correct answer)
In a circular pattern around the head
Diagonally from frontal to contralateral occipital
Front to back (anterior-posterior)

Correct answer: Left to right across the head (coronal)

Bipolar transverse montages chain electrodes from left to right across the head in coronal rows, complementing the longitudinal (anterior-posterior) montage and helping lateralize epileptiform discharges.

Question 91: What is the minimum recommended sampling rate for routine digital EEG recording?

128 Hz
1024 Hz
256 Hz (Correct answer)
64 Hz

Correct answer: 256 Hz

A sampling rate of at least 256 Hz is recommended for routine EEG to adequately capture frequencies up to 70-100 Hz according to the Nyquist theorem (sampling rate must be at least twice the highest frequency of interest).

Question 92: Which of the following is the LEAST likely cause of persistent 60 Hz electrical interference in an EEG recording?

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

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

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

Question 93: What is the typical duration criterion for an EEG spike?

70 to 200 milliseconds
200 to 500 milliseconds
Less than 20 milliseconds
20 to 70 milliseconds (Correct answer)

Correct answer: 20 to 70 milliseconds

By IFCN definition, a spike has a duration of 20 to 70 milliseconds, distinguishing it from sharp waves which last 70 to 200 milliseconds.

Question 94: If a routine EEG shows no epileptiform abnormalities, this means:

The patient's medication should be stopped immediately
No further testing is needed
A single normal EEG does not exclude epilepsy, as interictal sensitivity is approximately 50% for a single routine study (Correct answer)
The patient definitely does not have epilepsy

Correct answer: A single normal EEG does not exclude epilepsy, as interictal sensitivity is approximately 50% for a single routine study

A single normal routine EEG has limited sensitivity (approximately 50%) for detecting interictal epileptiform discharges. Epilepsy remains a clinical diagnosis, and serial or prolonged EEG studies increase diagnostic yield.

Question 95: On a neonatal EEG, which feature best distinguishes a seizure discharge from a normal sharp transient?

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

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

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

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.

Question 97: 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
Avoid placing electrodes over or applying pressure to the affected area, and consult with the clinical team (Correct answer)
No special precautions are needed — standard application applies
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 98: An EEG amplifier has a CMRR of 100 dB. This means the amplifier rejects common-mode signals by a factor of approximately:

10,000 times
100 times
1,000 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 99: Triphasic waves with anterior-to-posterior phase lag are most classically associated with which metabolic condition?

Hepatic encephalopathy (Correct answer)
Hyponatremia
Hypoglycemia
Hyperthyroidism

Correct answer: Hepatic encephalopathy

Triphasic waves — high-amplitude, anteriorly dominant complexes with three phases and an anterior-to-posterior time lag — are the classic EEG hallmark of hepatic (portosystemic) encephalopathy, though they can also appear in renal failure and other toxic-metabolic states. Recognizing this pattern and its metabolic context is essential for accurate reporting.

Question 100: Which cortical cell type is the primary generator of EEG signals recorded at the scalp?

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

Correct answer: Pyramidal neurons in cortical layers III and V

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

Question 101: During an EEG recording, a patient begins to have a generalized tonic-clonic seizure. What is the technologist's first priority?

Continue recording and immediately stop all activation procedures (Correct answer)
Restrain the patient to prevent movement artifact
Turn off the EEG machine to protect the equipment
Remove all electrodes before calling for help

Correct answer: Continue recording and immediately stop all activation procedures

The technologist's first priority is to ensure patient safety while continuing the recording. This means stopping any activation procedures (hyperventilation, photic stimulation) and ensuring the patient is safe from injury, while keeping the EEG recording to capture the seizure.

Question 102: Focal polymorphic delta activity (PDA) over the right temporal region in an awake adult most strongly suggests:

Normal drowsiness
A structural lesion in the right temporal area (Correct answer)
Medication effect from benzodiazepines
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 103: Anterior dysrhythmia (frontal sharp transients) in a premature neonate at 34 weeks conceptional age is considered:

Evidence of frontal lobe seizure activity
Always pathological requiring treatment
A normal developmental feature (encoches frontales) expected at this age (Correct answer)
An artifact from eye movements

Correct answer: A normal developmental feature (encoches frontales) expected at this age

Anterior dysrhythmia (encoches frontales or frontal sharp transients) is a normal developmental pattern in premature neonates from approximately 34-36 weeks conceptional age, appearing as bilateral frontal sharp waves during quiet sleep.

Question 104: Which evoked potential modality is specifically used to assess the integrity of the auditory pathway from the cochlea through the brainstem?

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

Correct answer: Brainstem Auditory Evoked Potentials (BAEP)

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

Question 105: Periodic discharges on the ictal-interictal continuum are challenging because:

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

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

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

Question 106: What are the typical high-pass and low-pass filter settings used when recording brainstem auditory evoked potentials (BAEPs)?

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

Correct answer: 100–3000 Hz

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

Question 107: Which electrode placement system uses 10% and 20% distances from skull landmarks to determine electrode positions?

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

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 108: 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:

EKG artifact
Muscle 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 109: In cEEG monitoring, an alpha coma pattern is characterized by:

Alpha rhythm appearing only during REM sleep
Reactive alpha in a drowsy but arousable patient
Diffuse, unreactive alpha-frequency activity in a comatose patient (Correct answer)
Frontal alpha with preserved posterior reactivity

Correct answer: Diffuse, unreactive alpha-frequency activity in a comatose patient

Alpha coma features widespread alpha or alpha-like activity that is unresponsive to external stimuli, often seen after cardiac arrest or pontine lesions, and carries a poor prognosis.

Question 110: A patient has recurrent brief lapses with 3-Hz spike-and-wave that are abruptly terminated by photic stimulation. This response pattern is called:

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

Correct answer: Photoparoxysmal response

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

Question 111: Which component of the EEG amplifier circuit is responsible for rejecting signals common to both inputs (such as 60 Hz power line noise)?

The electrode selector matrix
The low-frequency filter
The analog-to-digital converter
The differential amplifier (Correct answer)

Correct answer: The differential amplifier

The differential amplifier amplifies the difference between two inputs while rejecting signals that appear equally on both (common mode), which is how 60 Hz interference is suppressed.

Question 112: A cEEG monitoring technologist notices sudden onset of rhythmic, evolving 2 Hz sharp-wave activity for 90 seconds followed by postictal slowing. This is best classified as:

Breach rhythm
Lateralized periodic discharge
Rhythmic delta activity
Electrographic seizure (Correct answer)

Correct answer: Electrographic seizure

An electrographic seizure requires evolution in frequency, morphology, or spatial distribution lasting ≥10 seconds, and this pattern with evolution and postictal slowing meets criteria.

Question 113: What electrode application method is preferred for ambulatory EEG to ensure electrodes remain in place during extended recording?

Collodion adhesive (Correct answer)
Conductive gel alone
Paste with gauze
Saline-soaked sponges

Correct answer: Collodion adhesive

Collodion is the preferred adhesive for ambulatory EEG because it provides secure, long-lasting electrode fixation that withstands the physical activity of daily living during multi-day recordings.

Question 114: Beta activity (13-30 Hz) on the normal EEG is typically maximal over which brain region?

Temporal regions
Occipital regions
Parietal regions only
Frontal and central regions (Correct answer)

Correct answer: Frontal and central regions

Normal beta activity is most prominent over frontal and central regions, reflecting the activity of frontal cortical networks during alertness and cognitive processing.

Question 115: Waveforms connected to and unrelated from clinical seizure symptoms.

Paroxysmal
Interictal
The epileptiform (Correct answer)
Unusual Behavior

Correct answer: The epileptiform

Waveforms indicative of epilepsy or seizure activity are referred to as "epileptiforms". An electroencephalogram (EEG) can show these waves, which are usually aberrant in nature. Clinical seizure symptoms including convulsions or loss of consciousness are frequently linked to them. On the other hand, waveforms that do not exhibit clinical signs of seizures are classified as normal or non-epileptiform. Consequently, the best term to characterize waveforms linked to clinical seizure symptoms is "epileptiform".

Question 116: The high-frequency filter (low-pass filter) in EEG recording at a typical setting of 70 Hz will:

Block all frequencies below 70 Hz
Only display the 70 Hz component
Attenuate frequencies above 70 Hz while passing lower frequencies (Correct answer)
Amplify frequencies above 70 Hz

Correct answer: Attenuate frequencies above 70 Hz while passing lower frequencies

The high-frequency (low-pass) filter attenuates signals above its cutoff frequency. At 70 Hz, it progressively reduces muscle artifact and electrical noise above 70 Hz while preserving brain activity which is predominantly below 70 Hz.

Question 117: Which peripheral nerve is most commonly stimulated at the ankle when performing lower extremity somatosensory evoked potential (SSEP) testing?

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

Correct answer: Posterior tibial nerve

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

Question 118: 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?

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

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 119: What does the '10' and '20' refer to in the International 10-20 system?

Percentage of total skull distance between electrode sites (Correct answer)
Number of electrodes in each region
Frequency bands measured at each site
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 120: What does the term 'electrocerebral inactivity' (ECI) refer to in EEG?

Intermittent suppression during burst-suppression pattern
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
Normal low-voltage pattern during deep sleep

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

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

Correct answer: Vertex sharp wave

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

Question 122: Which of the following statements is true regarding beta activity in a normal adult EEG?

It is typically highest in amplitude in the occipital regions.
It is defined as activity in the 4-7 Hz frequency range.
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.

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

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

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

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

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 125: Impedance testing of EEG electrodes should ideally be performed using:

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

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

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

Question 126: Post-ictal slowing on EEG following a focal seizure is clinically useful because it:

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

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

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

Question 127: What is the standard low-frequency filter (LFF) setting used in routine clinical EEG?

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

Correct answer: 1 Hz

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

Question 128: What is the typical frequency range of theta activity in EEG?

8-13 Hz
0.5-4 Hz
4-8 Hz (Correct answer)
13-30 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 129: What property of pyramidal neurons makes them the primary generators of scalp-recorded EEG signals rather than stellate cells?

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

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

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

Question 130: What is the modified combinatorial nomenclature (MCN) designation for the traditional T3 electrode position?

FT7
T9
TP7
T7 (Correct answer)

Correct answer: T7

In the modified combinatorial nomenclature system, the traditional T3 position is redesignated as T7, following the logic that odd numbers indicate left hemisphere and the '7' indicates the temporal row position.

Question 131: Lambda waves in the EEG are best elicited by which condition?

Active visual scanning of a patterned surface (Correct answer)
Auditory stimulation
Eye closure in a dark room
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 132: 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:

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

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 133: What is the most effective method for reducing 60 Hz electrical interference artifact?

Switching to a bipolar montage
Increasing the high-frequency filter to 100 Hz
Ensuring all electrode impedances are balanced and below 5 kOhm (Correct answer)
Increasing the recording sensitivity

Correct answer: Ensuring all electrode impedances are balanced and below 5 kOhm

Balanced, low impedances (below 5 kOhm) allow the differential amplifier to effectively reject common-mode 60 Hz noise. Impedance imbalance between electrodes is the primary cause of excessive 60 Hz artifact.

Question 134: 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 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
Low-Frequency Filter (LFF) at 5 Hz, High-Frequency Filter (HFF) at 70 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 135: Waveforms connected to and unrelated from clinical seizure symptoms.

Interictal
The epileptiform (Correct answer)
Unusual Behavior
Pyroclastic

Correct answer: The epileptiform

Waveforms indicative of epilepsy or seizure activity are referred to as "epileptiforms". When performing an electroencephalogram (EEG), a test used to identify and track seizures, these waves can be seen. Abnormal electrical discharges in the brain called epileptiform waveforms are frequently linked to clinical seizure symptoms including convulsions or loss of consciousness. Consequently, the best term to characterize waveforms linked to clinical seizure symptoms is "epileptiform".

Question 136: When performing EEG on a patient with an implanted cardiac defibrillator (ICD), the technologist should:

Only use 4 electrodes to minimize electromagnetic interference
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)
Refuse to perform the study as it is absolutely contraindicated
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 137: A patient post-cardiac arrest shows an EEG with suppression-burst ratio >50% and identical burst morphology across channels. What does this suggest?

Therapeutic hypothermia artifact
Favorable prognosis for neurological recovery
Severe diffuse cortical injury with poor prognosis (Correct answer)
Focal cortical dysplasia

Correct answer: Severe diffuse cortical injury with poor prognosis

High suppression-burst ratios with stereotyped bursts in post-cardiac arrest patients indicate severe anoxic brain injury and are associated with poor neurological outcomes.

Question 138: 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 139: What is the most important factor in interpreting a neonatal EEG?

Whether the recording is digital or analog
The number of electrodes used
The conceptional age (gestational age plus postnatal age) of the infant (Correct answer)
The ambient room temperature during recording

Correct answer: The conceptional age (gestational age plus postnatal age) of the infant

Conceptional age is the single most important factor in neonatal EEG interpretation because normal EEG patterns change dramatically with brain maturation, and age-inappropriate patterns indicate abnormality.

Question 140: Subclinical rhythmic electrographic discharges of adults (SREDA) is a rare benign pattern that mimics:

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

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

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

Question 141: 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 142: Which of the following statements accurately describes the fundamental principle of a bipolar montage?

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

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

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

Question 143: 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?

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

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

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

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

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

Question 145: Which of the following actions by an EEG technologist is a direct violation of the Health Insurance Portability and Accountability Act (HIPAA)?

Discussing a complex EEG record with the interpreting neurologist in a private reading room.
Calling the patient's nurse to confirm their current list of medications.
Looking up the medical records of a celebrity who is a patient in another part of the hospital out of curiosity. (Correct answer)
Using a hospital-provided, encrypted tablet to review a patient's prior EEG report.

Correct answer: Looking up the medical records of a celebrity who is a patient in another part of the hospital out of curiosity.

Accessing a patient's protected health information (PHI) without a legitimate, job-related reason is a serious HIPAA violation. Curiosity is not a valid reason for accessing records. The other options describe appropriate actions: consulting with the care team, using secure devices, and gathering necessary clinical information are all permissible uses of PHI for patient care.

Question 146: A compressed spectral array (CSA) displays EEG information by showing:

Raw EEG waveforms compressed to fit on a single page per hour
Power spectral density plotted over time, with frequency on one axis and time on the other (Correct answer)
Amplitude envelope of the raw EEG plotted as a single line per channel
Spike-and-wave discharge counts per epoch displayed as a histogram

Correct answer: Power spectral density plotted over time, with frequency on one axis and time on the other

A CSA (also called a density spectral array or DSA depending on color coding) uses Fast Fourier Transform (FFT) to decompose the EEG into its component frequencies and plots the power at each frequency band over time. This allows hours of EEG to be reviewed at a glance for trends in frequency content, making it useful for detecting delayed cerebral ischemia, seizures, and drug effects.

Question 147: Which EEG pattern in a neonate is characterized by high-amplitude bursts separated by periods of relative quiescence and is considered normal in premature infants?

Burst suppression
Trace alternant (Correct answer)
Hypsarrhythmia
Delta brushes

Correct answer: Trace alternant

Trace alternant is a normal sleep pattern in term and preterm neonates consisting of high-amplitude bursts alternating with lower-amplitude inter-burst intervals.

Question 148: A burst suppression pattern on EEG is most consistent with which clinical scenario?

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

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 149: On EEG, a burst-suppression pattern in a neonate without hypothermia treatment most likely indicates which condition?

Normal preterm variant
Hypoxic-ischemic encephalopathy grade I
Ohtahara syndrome (Correct answer)
Benign neonatal sleep myoclonus

Correct answer: Ohtahara syndrome

Burst-suppression in a neonate (outside therapeutic hypothermia) is a hallmark of Ohtahara syndrome (early infantile epileptic encephalopathy).

Question 150: Which artifact would most likely appear as a high-amplitude, low-frequency deflection time-locked to the R-wave on ECG?

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

Correct answer: Pulse artifact

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

Question 151: According to American Clinical Neurophysiology Society (ACNS) and AAN guidelines, what is the minimum sensitivity required when recording an EEG to assess for electrocerebral inactivity (ECI)?

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

Correct answer: 2 µV/mm

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

Question 152: Sleep deprivation before an EEG is primarily used to:

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

Correct answer: Increase the likelihood of recording epileptiform discharges

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

Question 153: The posterior dominant rhythm (alpha rhythm) in a normal awake adult is generated primarily by which brain structure interaction?

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

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 154: ____ pounds is the typical weight of a human brain?

5
6
3 (Correct answer)
8

Correct answer: 3

A human brain typically weighs three pounds.

Question 155: Which electrode placement is standard for detecting eye movements during sleep staging PSG?

C3-A2 and C4-A1
Fp1-Fp2 bipolar pair
E1-M2 and E2-M2 (outer canthi referenced to contralateral mastoid) (Correct answer)
F7-F8 bipolar pair

Correct answer: E1-M2 and E2-M2 (outer canthi referenced to contralateral mastoid)

EOG channels placed at the outer canthi (E1, E2) referenced to mastoids capture horizontal and vertical eye movements needed for sleep staging.

Question 156: To minimize the risk of electrical shock to the patient, what is the single most important electrical safety practice in the EEG laboratory?

Using a notch filter to remove 60 Hz interference.
Ensuring all electrodes have an impedance below 1 kOhm.
Plugging all patient-connected equipment into the same properly grounded, hospital-grade outlet cluster. (Correct answer)
Applying a separate ground electrode for each piece of monitoring equipment.

Correct answer: Plugging all patient-connected equipment into the same properly grounded, hospital-grade outlet cluster.

Using a single, common ground point for all equipment connected to the patient prevents the formation of ground loops and minimizes the risk of leakage currents passing through the patient. Plugging the EEG machine and any other connected devices into the same outlet block ensures they share a common ground reference. Applying multiple ground electrodes from different pieces of equipment can be dangerous and is known as 'double grounding'.

Question 157: 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)
Wakefulness with eyes open
REM sleep only

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

A highly pathological pattern requiring immediate treatment
A benign normal variant seen in adolescents during drowsiness and light sleep (Correct answer)
An indicator of deep midline structural lesion
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 159: AAN guidelines for ECI recordings require a minimum interelectrode distance of at least how many centimeters to avoid missing low-amplitude activity between nearby electrodes?

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

Correct answer: 10 cm

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

Question 160: An asymmetry in the posterior dominant rhythm amplitude, with the right side consistently 50% lower than the left, suggests:

Normal variant — mild asymmetry is always benign
Possible structural or functional abnormality of the right hemisphere (Correct answer)
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 161: Which antiepileptic drug effect on the EEG may be mistaken for a pathological finding if the technologist is unaware of the patient's medication list?

Carbamazepine causing bifrontal spike-and-wave discharges
Valproate at therapeutic levels causing diffuse slowing that mimics metabolic encephalopathy (Correct answer)
Lamotrigine causing prominent mu rhythm enhancement
Phenytoin toxicity causing rhythmic beta activity indistinguishable from normal

Correct answer: Valproate at therapeutic levels causing diffuse slowing that mimics metabolic encephalopathy

Valproate, even at therapeutic serum levels, can produce diffuse background slowing that resembles a mild encephalopathy. Without knowing the patient is on valproate, the EEG reader could incorrectly diagnose a metabolic or structural abnormality. This is a common source of interpretation error and underscores the importance of obtaining a complete medication history before interpreting any EEG.

Question 162: In a term neonate, which finding on EEG is most consistent with hypoxic-ischemic encephalopathy (HIE)?

Burst suppression with prolonged inter-burst intervals (Correct answer)
Well-organized trace alternant
Abundant sleep spindles
Continuous high-amplitude delta activity

Correct answer: Burst suppression with prolonged inter-burst intervals

Burst suppression with prolonged inter-burst intervals (>10 seconds) in a term neonate is a marker of severe cerebral dysfunction associated with HIE.

Question 163: 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
Persistent beta spindle activity
Well-organized posterior dominant rhythm
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 164: What are the three main types of evoked potentials commonly recorded in a clinical neurophysiology laboratory?

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

Correct answer: Visual, Auditory, and Somatosensory

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

Question 165: What is the primary safety concern when performing EEG on a patient in the ICU with external ventricular drains?

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

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 166: 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)
11-12 Hz
4-5 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 167: Eye blink artifact is primarily seen at which electrode positions?

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

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

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

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 169: Which EEG pattern in a comatose patient is most associated with nonconvulsive status epilepticus (NCSE)?

Burst suppression with flat interburst intervals
Diffuse slowing with theta predominance
Rhythmic or periodic discharges evolving in frequency or morphology (Correct answer)
Alpha coma pattern with unreactive background

Correct answer: Rhythmic or periodic discharges evolving in frequency or morphology

Rhythmic or periodic discharges that evolve in frequency, morphology, or spatial distribution are the hallmark EEG feature of NCSE in critically ill patients.

Question 170: Sphenoidal electrodes are used to improve detection of epileptiform discharges from which brain region?

Parietal lobe parasagittal area
Frontal lobe convexity
Mesial temporal lobe structures (Correct answer)
Occipital cortex

Correct answer: Mesial temporal lobe structures

Sphenoidal electrodes are inserted near the foramen ovale to record from the inferomedial temporal region, improving detection of mesial temporal epileptiform activity that may not reach standard scalp electrodes.

Question 171: The synchronization of cortical neurons necessary to produce normal resting rhythms and abnormal discharges like generalized spike-and-wave is heavily dependent on the integrity of:

Corticothalamic circuits (Correct answer)
Corticospinal tracts
Corpus callosum pathways
The fornix and limbic pathways

Correct answer: Corticothalamic circuits

Corticothalamic circuits, the reciprocal connections between the cortex and the thalamus, are fundamental for synchronizing neuronal activity across large brain regions. These circuits are responsible for pacing normal rhythms like sleep spindles and the alpha rhythm, and their dysfunction is implicated in the generation of widespread, synchronized discharges seen in generalized epilepsies.

Question 172: During sleep recording, repetitive, high-amplitude spike-like potentials appearing synchronously with each heartbeat across all leads are best identified as:

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

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 173: Which electrode placement best captures activity from the temporal lobe?

O1/O2
P3/P4
F3/F4
T3/T4 (T7/T8) (Correct answer)

Correct answer: T3/T4 (T7/T8)

T3/T4 (now called T7/T8 in the revised system) are positioned over the temporal lobes and best capture temporal lobe activity.

Question 174: Photic stimulation at what flash frequency range is most likely to provoke a photoparoxysmal response in susceptible individuals?

30-40 Hz
15-20 Hz (Correct answer)
50-60 Hz
1-3 Hz

Correct answer: 15-20 Hz

The photoparoxysmal response, characterized by generalized spike-and-wave or polyspike-and-wave discharges, is most commonly elicited at flash frequencies between 15-20 Hz.

Question 175: FIRDA (Frontal Intermittent Rhythmic Delta Activity) is most commonly associated with which condition?

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

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

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

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

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

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

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

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

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

Correct answer: Burst-suppression

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

Question 180: An EEG technologist is setting up for a routine adult EEG. According to the International 10-20 System, what are the four primary anatomical landmarks used to ensure standardized and proportional electrode placement?

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

Correct answer: Nasion, inion, and both preauricular points

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

Question 181: During a routine outpatient EEG, a patient discloses they are currently experiencing active suicidal ideation. What is the technologist's first action?

Complete the EEG as planned, then document the disclosure at the end of the session
Do not engage further to avoid worsening distress
Immediately alert clinical staff or a supervisor and ensure the patient is not left alone (Correct answer)
Ask the patient to contact their own therapist after leaving the facility

Correct answer: Immediately alert clinical staff or a supervisor and ensure the patient is not left alone

Active suicidal ideation is a psychiatric emergency requiring immediate notification of clinical staff and continuous patient supervision.

Question 182: A patient shows repeated brief arousals out of N3 sleep in the first third of the night without awakening. This pattern is most consistent with:

Sleep-onset insomnia
Sleep terror disorder (Correct answer)
Narcolepsy
REM sleep behavior disorder

Correct answer: Sleep terror disorder

Sleep terrors (NREM parasomnias) classically arise from N3 slow-wave sleep in the early part of the night with partial arousals and autonomic activation.

Question 183: Spectral edge frequency (SEF95) is defined as the frequency below which what percentage of the total EEG spectral power is contained?

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

Correct answer: 95%

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

Question 184: Hypsarrhythmia on EEG is the interictal hallmark of which epilepsy syndrome?

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

Correct answer: West syndrome

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

Question 185: Informed consent for EEG should include information about which potential discomfort or risk?

Risk of permanent brain damage from the recording
Risk of electric shock from the EEG machine
Skin irritation from electrode adhesive and small possibility of seizure provocation during activation procedures (Correct answer)
Radiation exposure during the recording

Correct answer: Skin irritation from electrode adhesive and small possibility of seizure provocation during activation procedures

Informed consent should cover possible skin irritation from electrode paste or adhesive (collodion), mild discomfort from skin preparation, and the small risk that activation procedures could provoke a seizure in susceptible individuals.

Question 186: What is the purpose of recording a period of wakefulness with eyes open and eyes closed before activation procedures?

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

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

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

Question 187: In neonatal EEG, what does the term 'dysmature' pattern refer to?

A pattern caused by maternal medication effects
A pattern with excessive fast activity for the infant's age
Normal variability in neonatal EEG patterns
An EEG pattern that appears normal but for a younger conceptional age than the infant's actual age, suggesting delayed brain maturation (Correct answer)

Correct answer: An EEG pattern that appears normal but for a younger conceptional age than the infant's actual age, suggesting delayed brain maturation

A dysmature EEG pattern shows features appropriate for a younger conceptional age than the infant's actual age, indicating delayed cerebral maturation which may result from prematurity complications, hypoxic-ischemic injury, or other insults.

Question 188: Centrotemporal spikes (rolandic spikes) in a child are associated with which EEG characteristic regarding sleep?

They occur exclusively during drowsiness
They are only seen during REM sleep
They increase in frequency and may become bilateral during NREM sleep (Correct answer)
They disappear entirely during NREM sleep

Correct answer: They increase in frequency and may become bilateral during NREM sleep

Centrotemporal spikes in benign epilepsy with centrotemporal spikes (BECTS) are markedly activated and may spread bilaterally during NREM sleep.

Question 189: The wicket rhythm is a benign normal variant that can be confused with:

Temporal sharp waves or epileptiform discharges (Correct answer)
Sleep spindles
Occipital spikes
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 190: Which ICU patient population has the highest risk of nonconvulsive seizures, justifying prompt cEEG monitoring?

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

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

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

Question 191: 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?

Basal Ganglia
Thalamus (Correct answer)
Hippocampus
Cerebellum

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

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

Correct answer: The midline frontal position

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

Question 193: How can chewing artifact be distinguished from rhythmic temporal seizure activity?

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

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

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

Question 194: What is the standard duration of a routine EEG recording?

5-10 minutes
60-90 minutes
20-30 minutes (Correct answer)
4-6 hours

Correct answer: 20-30 minutes

A standard routine EEG typically records for 20-30 minutes, providing adequate time for baseline recording, activation procedures (hyperventilation and photic stimulation), and ideally capturing some drowsiness.

Question 195: The mu rhythm, typically recorded over the central regions, is characterized by:

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

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

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

Question 196: The 'N13' potential recorded at the cervical spine (Cv5 or Cv7 electrode) during median nerve SSEP is generated by which structure?

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

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

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

Question 197: Temporal intermittent rhythmic delta activity (TIRDA) is significant because it:

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

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

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

Question 198: The reticular activating system (RAS) primarily influences EEG by:

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

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

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

Question 199: 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 symmetry of the waveforms.
The frequency of the transients.
The patient's state of consciousness. (Correct answer)

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

5 cm
10 cm
30 cm (Correct answer)
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 201: An EEG technologist is performing a biological calibration. The patient is asked to open and close their eyes, look left and right, and clench their jaw. What is the primary purpose of this procedure?

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

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

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

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%

To Pass

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