Q.1 Which of the following frequency bands is most commonly associated with the alpha rhythm in an EEG recording?
0.5–4 Hz (Delta)
4–8 Hz (Theta)
8–13 Hz (Alpha)
13–30 Hz (Beta)
Explanation - The alpha rhythm is traditionally defined as the 8–13 Hz band, most prominent when a subject is relaxed with eyes closed.
Correct answer is: 8–13 Hz (Alpha)
Q.2 Which electrode placement system is used worldwide for standardized EEG recordings?
10–20 System
Frontal–Parietal System
C7–C8 System
L1–L2 System
Explanation - The International 10–20 system specifies electrode positions relative to the nasion, inion, and preauricular points.
Correct answer is: 10–20 System
Q.3 Which artifact is most likely to appear as a large spike in an EEG during sudden eye closure?
Cardiac artifact
Muscle artifact
Electrooculographic (EOG) artifact
Movement artifact
Explanation - Eye movements and blinks generate strong potentials recorded as spikes or slow waves in the EEG.
Correct answer is: Electrooculographic (EOG) artifact
Q.4 What is the primary clinical use of an EEG in newborns?
Detecting congenital heart defects
Assessing cranial nerve function
Diagnosing neonatal seizures
Measuring blood glucose levels
Explanation - EEG is critical for detecting epileptiform activity in neonates, guiding anticonvulsant therapy.
Correct answer is: Diagnosing neonatal seizures
Q.5 In EEG signal processing, which filter type is commonly used to remove power line interference at 60 Hz?
High-pass filter
Low-pass filter
Notch filter
Band-stop filter
Explanation - A notch filter centered at 60 Hz (or 50 Hz) attenuates power line noise while preserving surrounding frequencies.
Correct answer is: Notch filter
Q.6 Which of the following statements best describes the Nyquist criterion for EEG sampling?
Sampling rate should be at least twice the highest signal frequency.
Sampling rate should be equal to the highest signal frequency.
Sampling rate should be half the lowest signal frequency.
Sampling rate is irrelevant for EEG.
Explanation - Nyquist theorem ensures accurate reconstruction by sampling at ≥2× highest frequency component.
Correct answer is: Sampling rate should be at least twice the highest signal frequency.
Q.7 What is the typical range of impedance values for a good EEG electrode contact?
0–5 Ω
30–50 Ω
100–200 Ω
10–30 kΩ
Explanation - EEG electrodes aim for impedance below 10–30 kΩ to minimize noise, though some protocols accept up to 50 kΩ.
Correct answer is: 10–30 kΩ
Q.8 Which EEG frequency band is most prominent during deep, dreamless sleep?
Delta (0.5–4 Hz)
Theta (4–8 Hz)
Alpha (8–13 Hz)
Beta (13–30 Hz)
Explanation - Delta waves dominate in stages N3 of slow‑wave sleep, reflecting deep, restorative sleep.
Correct answer is: Delta (0.5–4 Hz)
Q.9 Which EEG feature is often used to differentiate between focal and generalized seizures?
Presence of high‑frequency bursts
Location of initial epileptiform spikes
Amplitude of alpha rhythm
Duration of the EEG recording
Explanation - Focal seizures originate in a limited cortical area, whereas generalized seizures involve both hemispheres simultaneously.
Correct answer is: Location of initial epileptiform spikes
Q.10 Which of the following electrodes is most sensitive to the occipital lobe activity?
Fz
C3
O1
T3
Explanation - O1 is positioned over the left occipital lobe, making it ideal for recording visual cortex activity.
Correct answer is: O1
Q.11 In an EEG, a rhythmic burst of 3–4 Hz activity that occurs during eye closure is most likely to represent what?
Delta burst
Beta burst
Alpha burst
Theta burst
Explanation - Theta rhythm (4–8 Hz) can appear during relaxation and eye closure, especially in older adults.
Correct answer is: Theta burst
Q.12 Which of the following best describes the term 'background activity' in an EEG?
The most prominent oscillation present when the subject is at rest.
The high‑frequency noise from muscle artifacts.
The slow waves seen during deep sleep.
The spike‑and‑wave complexes of epilepsy.
Explanation - Background activity refers to the dominant rhythm (e.g., alpha during relaxation) in the absence of stimulation.
Correct answer is: The most prominent oscillation present when the subject is at rest.
Q.13 Which artifact is caused by electrode movement relative to the scalp?
Power line interference
EOG artifact
Movement artifact
Muscle artifact
Explanation - Shifting electrodes produce abrupt voltage changes, seen as artifacts in the recording.
Correct answer is: Movement artifact
Q.14 Which of the following is a common non‑clinical application of EEG?
Measuring blood pressure
Brain‑computer interface development
Detecting bone fractures
Assessing liver function
Explanation - EEG signals are used in BCIs to translate brain activity into computer commands.
Correct answer is: Brain‑computer interface development
Q.15 Which EEG frequency band is typically associated with active problem solving and concentration?
Alpha
Beta
Delta
Theta
Explanation - Beta waves (13–30 Hz) are linked to alertness, focus, and cognitive processing.
Correct answer is: Beta
Q.16 What is the main difference between an active and a passive EEG electrode?
Active electrodes use a preamplifier at the contact point; passive electrodes do not.
Passive electrodes have a larger surface area.
Active electrodes are only used in research settings.
Passive electrodes require external power supply.
Explanation - Active electrodes include an integrated preamplifier to boost signal and reduce noise, improving signal quality.
Correct answer is: Active electrodes use a preamplifier at the contact point; passive electrodes do not.
Q.17 Which EEG phenomenon is characterized by a 3–4 Hz rhythmic spike‑and‑wave pattern?
Generalized tonic‑clonic seizures
Absence seizures
Myoclonic seizures
Focal seizures
Explanation - Absence seizures show 3–4 Hz spike‑and‑wave complexes in the EEG.
Correct answer is: Absence seizures
Q.18 Which of the following best describes the term 'clinical significance' of an EEG finding?
Whether the EEG is legally admissible.
The degree to which the EEG informs patient care.
The presence of artifacts in the recording.
The number of electrodes used.
Explanation - Clinical significance refers to how an EEG finding affects diagnosis, treatment, or prognosis.
Correct answer is: The degree to which the EEG informs patient care.
Q.19 Which type of electrode is commonly used for EMG recordings during muscle contraction tests?
Dry electrodes
Surface electrodes
Invasive needle electrodes
Both surface and needle electrodes
Explanation - Surface electrodes are non‑invasive, while needle electrodes provide deeper muscle activity, each used depending on the assessment.
Correct answer is: Both surface and needle electrodes
Q.20 What is the typical amplitude range of a surface EMG signal?
0.1–1 μV
1–5 mV
10–50 μV
0.1–1 mV
Explanation - Surface EMG signals usually range from 0.1 to 1 millivolt during voluntary contraction.
Correct answer is: 0.1–1 mV
Q.21 Which EMG signal component represents the frequency content of muscle activity?
Time domain
Frequency domain
Phase domain
Amplitude domain
Explanation - Spectral analysis of EMG yields information about motor unit firing rates and muscle fatigue.
Correct answer is: Frequency domain
Q.22 In surface EMG, what does a higher root‑mean‑square (RMS) value indicate?
Lower muscle activation
Higher muscle activation
More noise
Artifact contamination
Explanation - RMS amplitude is proportional to the level of muscle activation during contraction.
Correct answer is: Higher muscle activation
Q.23 Which of the following is a common artifact in EMG recordings?
Eye blinks
Cardiac activity
Jaw movement
Respiratory cycle
Explanation - Jaw clenching produces strong electrical potentials that can contaminate EMG signals of facial muscles.
Correct answer is: Jaw movement
Q.24 Which EMG technique is used to assess muscle fatigue during prolonged activity?
Amplitude modulation
Frequency shift analysis
Power line filtering
Artifact rejection
Explanation - A shift to lower frequency content in EMG indicates developing fatigue.
Correct answer is: Frequency shift analysis
Q.25 Which type of EMG electrode is most suitable for intra‑operative neuromonitoring during spinal surgery?
Surface electrodes
Fine‑wire needle electrodes
Subdermal needle electrodes
Disposable adhesive electrodes
Explanation - Fine‑wire needles allow precise placement in target nerves or muscles while minimizing tissue disruption.
Correct answer is: Fine‑wire needle electrodes
Q.26 Which of the following best defines the term 'motor unit action potential' in EMG?
The electrical activity of a single neuron in the CNS.
The combined electrical response of all muscles in the body.
The composite electrical activity generated by a single motor neuron and all the muscle fibers it innervates.
The voltage measured across the skin surface during EMG.
Explanation - A motor unit action potential reflects the synchronized activation of all muscle fibers driven by one motor neuron.
Correct answer is: The composite electrical activity generated by a single motor neuron and all the muscle fibers it innervates.
Q.27 What is the typical frequency range of a normal surface EMG signal?
0–50 Hz
20–200 Hz
100–500 Hz
1–10 kHz
Explanation - Muscle action potentials produce frequencies predominantly in the 20–200 Hz band.
Correct answer is: 20–200 Hz
Q.28 Which of the following best describes 'myoelectric amplification' in EMG?
Reducing the EMG signal to increase signal‑to‑noise ratio.
Increasing the amplitude of EMG signals to make them measurable.
Filtering out frequencies below 10 Hz.
Applying a notch filter at 60 Hz.
Explanation - Myoelectric amplification boosts the small EMG potentials for easier detection by the recording system.
Correct answer is: Increasing the amplitude of EMG signals to make them measurable.
Q.29 Which of the following clinical conditions is commonly evaluated using surface EMG?
Hypertension
Peripheral neuropathy
Gastroesophageal reflux disease
Chronic obstructive pulmonary disease
Explanation - EMG is used to assess nerve conduction and muscle response in peripheral neuropathies.
Correct answer is: Peripheral neuropathy
Q.30 Which EMG technique is used to estimate the recruitment order of motor units?
Amplitude analysis
Frequency decomposition
Time‑frequency mapping
Spike‑train analysis
Explanation - Spike‑train analysis of motor unit potentials reveals the temporal recruitment sequence.
Correct answer is: Spike‑train analysis
Q.31 In an EMG recording, a sudden increase in signal amplitude lasting 50–100 ms is most likely indicative of what?
Muscle fatigue
Electrical interference
Twitch or myokymia
Heart rate variability
Explanation - Brief, isolated bursts of high‑amplitude EMG activity are characteristic of involuntary muscle twitches.
Correct answer is: Twitch or myokymia
Q.32 Which of the following is NOT a factor that affects the quality of EMG recordings?
Electrode placement
Skin preparation
Ambient temperature
Electrode impedance
Explanation - While temperature can influence comfort, it does not directly alter EMG signal quality as the other factors do.
Correct answer is: Ambient temperature
Q.33 Which type of EMG recording is used to monitor diaphragmatic activity during mechanical ventilation?
Surface EMG of the chest
Needle EMG of the diaphragm
Surface EMG of the limb muscles
Subdermal EMG of the back
Explanation - Needle electrodes placed near the diaphragm provide direct measurement of respiratory muscle activity.
Correct answer is: Needle EMG of the diaphragm
Q.34 What does the term 'myoelectric prosthesis' refer to?
A device that uses EMG signals to control artificial limbs.
A diagnostic test for muscle disorders.
An EMG recording system with built‑in amplifiers.
A surgical implant for nerve regeneration.
Explanation - Myoelectric prostheses interpret EMG from residual muscles to generate prosthetic movements.
Correct answer is: A device that uses EMG signals to control artificial limbs.
Q.35 Which of the following best describes the term 'crosstalk' in EMG?
Electrical interference from the power grid.
Signal contamination from adjacent muscles.
Artifacts due to electrode movement.
Noise introduced by the recording equipment.
Explanation - Crosstalk occurs when EMG from neighboring muscles is picked up by the electrode array.
Correct answer is: Signal contamination from adjacent muscles.
Q.36 Which EMG analysis technique is useful for estimating motor unit firing rates?
Time‑domain RMS
Frequency‑domain spectral density
Spike‑sorting
Amplitude‑phase analysis
Explanation - Spike‑sorting separates individual motor unit action potentials, allowing firing rate estimation.
Correct answer is: Spike‑sorting
Q.37 In an EEG recording, a sudden, short burst of high‑frequency activity that lasts less than 200 ms and appears in one electrode is most likely to be which of the following?
Inter‑ictal spike
Eye blink artifact
Movement artifact
Muscle artifact
Explanation - Inter‑ictal spikes are brief, sharp transients often seen in epilepsy patients.
Correct answer is: Inter‑ictal spike
Q.38 Which of the following is a typical artifact produced by poor electrode contact in EEG?
Sharp spikes
Flatline
High‑frequency noise
Slow drifts
Explanation - Poor contact can cause a complete loss of signal, resulting in a flatline segment.
Correct answer is: Flatline
Q.39 Which EEG rhythm is most prominent during REM sleep?
Delta
Theta
Alpha
Beta
Explanation - REM sleep displays low‑amplitude, high‑frequency activity similar to wakefulness, often in the beta range.
Correct answer is: Beta
Q.40 Which of the following best describes the 'gold standard' for diagnosing amyotrophic lateral sclerosis (ALS) using EMG?
Nerve conduction velocity testing
Fine‑needle EMG of multiple muscles
Resting EMG only
High‑density surface EMG of the upper limbs
Explanation - ALS diagnosis often relies on needle EMG to detect fibrillation potentials and positive sharp waves.
Correct answer is: Fine‑needle EMG of multiple muscles
Q.41 Which of the following statements about EEG power spectral density is true?
It shows the amplitude of each frequency component over time.
It is computed by applying a Fast Fourier Transform to the EEG data.
It measures the voltage difference between two electrodes.
It is used only in research, not clinical practice.
Explanation - Power spectral density is derived via FFT, revealing the energy distribution across frequencies.
Correct answer is: It is computed by applying a Fast Fourier Transform to the EEG data.
Q.42 Which EEG feature is most associated with generalized epilepsy?
Focal spike‑and‑wave complexes
Diffuse 3–4 Hz spike‑and‑wave patterns
High‑amplitude delta waves
Occipital alpha slowing
Explanation - Generalized epilepsy often shows synchronous spike‑and‑wave activity across the brain.
Correct answer is: Diffuse 3–4 Hz spike‑and‑wave patterns
Q.43 Which of the following best describes 'burst suppression' in EEG?
Continuous high‑frequency oscillations.
Alternating periods of high amplitude bursts and flat periods.
Persistent slow waves.
Sharp spikes every few seconds.
Explanation - Burst suppression is characteristic of severe cerebral dysfunction, with clear bursts and suppressions.
Correct answer is: Alternating periods of high amplitude bursts and flat periods.
Q.44 Which of the following is a key parameter used in EMG to evaluate muscle contraction force?
Signal amplitude
Signal frequency
Signal phase
Signal impedance
Explanation - Higher amplitude in EMG correlates with greater motor unit recruitment, reflecting force production.
Correct answer is: Signal amplitude
Q.45 What is the typical duration of a motor unit action potential in a surface EMG recording?
0.1–0.5 ms
1–2 ms
5–10 ms
20–30 ms
Explanation - Surface EMG motor unit potentials generally last about 1–2 milliseconds.
Correct answer is: 1–2 ms
Q.46 Which of the following best explains why EMG is performed with electrodes placed over the skin surface rather than directly on muscle?
Surface electrodes are less invasive and provide sufficient signal for many assessments.
Surface electrodes are more expensive but more accurate.
Direct muscle contact is prohibited by regulations.
Skin surface recordings have higher impedance.
Explanation - Surface EMG is non‑invasive and suitable for routine functional testing.
Correct answer is: Surface electrodes are less invasive and provide sufficient signal for many assessments.
Q.47 Which of the following best describes 'electromyographic fatigue index'?
Ratio of high‑frequency to low‑frequency power in EMG.
The total duration of muscle contraction.
The average EMG amplitude over time.
The change in RMS value after fatigue.
Explanation - A decline in high‑frequency power relative to low‑frequency power indicates fatigue.
Correct answer is: Ratio of high‑frequency to low‑frequency power in EMG.
Q.48 Which of the following EEG artifacts is most likely caused by chewing or jaw clenching?
Cardiac artifact
Muscle artifact
Electrooculographic artifact
Power line artifact
Explanation - Jaw clenching activates facial muscles, generating high‑frequency EMG contamination.
Correct answer is: Muscle artifact
Q.49 Which of the following is a common method to reduce crosstalk in EMG recordings?
Using high‑gain amplifiers
Placing electrodes over the same muscle belly
Using bipolar electrode configuration
Increasing sampling frequency
Explanation - Bipolar pairs can cancel out signals from surrounding muscles, reducing crosstalk.
Correct answer is: Using bipolar electrode configuration
Q.50 Which of the following is a primary limitation of surface EMG?
Inability to detect deep muscle activity.
High susceptibility to motion artifacts.
Invasive nature of electrodes.
Requirement for skin preparation with alcohol.
Explanation - Surface electrodes cannot reliably pick up signals from deep muscles beneath other tissue layers.
Correct answer is: Inability to detect deep muscle activity.
Q.51 Which of the following is NOT typically recorded during an EEG study of a patient with suspected epilepsy?
Resting wakefulness
Eyes‑closed rest
Video monitoring
Immediate blood glucose measurement
Explanation - EEG studies focus on electrical brain activity; blood glucose is not part of routine EEG recording.
Correct answer is: Immediate blood glucose measurement
Q.52 Which of the following best explains why the EEG of a sleeping infant shows a predominance of slow waves?
Infants have higher heart rates.
The brain is still developing and uses more delta activity during sleep.
Infants have larger skulls.
Infant EEGs are recorded with higher sampling rates.
Explanation - Infants exhibit prolonged slow‑wave sleep, reflecting immature cortical networks.
Correct answer is: The brain is still developing and uses more delta activity during sleep.
Q.53 Which of the following is a key parameter used to assess muscle force generation via EMG?
Root‑mean‑square (RMS) amplitude
Signal impedance
Electrode size
Sampling frequency
Explanation - RMS of the EMG signal correlates linearly with muscle force during isotonic contractions.
Correct answer is: Root‑mean‑square (RMS) amplitude
Q.54 Which of the following best describes the difference between EEG and EMG signal amplitude scales?
EEG amplitudes are typically in the microvolt range, while EMG amplitudes are in the millivolt range.
EEG amplitudes are in millivolts, EMG in microvolts.
Both EEG and EMG amplitudes are in the same scale.
EEG amplitudes are always higher than EMG amplitudes.
Explanation - EEG signals are smaller (µV) compared to EMG signals (mV).
Correct answer is: EEG amplitudes are typically in the microvolt range, while EMG amplitudes are in the millivolt range.
Q.55 Which of the following is a typical indication for performing a long‑term ambulatory EEG?
Sudden cardiac arrest
Unexplained seizures that occur intermittently
Routine hearing assessment
Routine blood sugar monitoring
Explanation - Ambulatory EEG captures seizures that are infrequent and may not occur in a clinical setting.
Correct answer is: Unexplained seizures that occur intermittently
Q.56 Which of the following best describes 'phase‑locked' EMG activity?
EMG activity that occurs randomly with respect to a stimulus.
EMG activity that is synchronized with a reference signal, such as a voluntary contraction.
EMG activity that only appears during rest.
EMG activity that is blocked by medication.
Explanation - Phase‑locked signals maintain a consistent timing relationship with another event.
Correct answer is: EMG activity that is synchronized with a reference signal, such as a voluntary contraction.
Q.57 Which EEG electrode placement is used to monitor the anterior cingulate cortex during tasks involving decision making?
Fp1
Fz
Pz
Oz
Explanation - Fz is positioned over the frontal midline, near the anterior cingulate cortex.
Correct answer is: Fz
Q.58 Which of the following best explains why the EEG recording may show a sudden, brief spike followed by a slow wave in a patient with epilepsy?
Artifact from a power supply.
Inter‑ictal spike‑and‑wave complex.
Movement artifact during sleep.
Muscle artifact from jaw clenching.
Explanation - Spike‑and‑wave complexes are characteristic of epileptiform discharges.
Correct answer is: Inter‑ictal spike‑and‑wave complex.
Q.59 In surface EMG, what is the main purpose of using a high‑pass filter with a cutoff around 20 Hz?
To remove high‑frequency noise.
To attenuate motion artifacts and low‑frequency drift.
To isolate alpha waves.
To reduce power line interference.
Explanation - A high‑pass filter removes slow baseline shifts, improving the integrity of the EMG signal.
Correct answer is: To attenuate motion artifacts and low‑frequency drift.
Q.60 Which of the following best describes the 'beta block' phenomenon in EEG?
A sudden reduction in beta band activity during drowsiness.
An increase in beta waves during seizures.
Beta waves appearing in the occipital lobe during REM sleep.
The presence of beta waves in muscle activity during rest.
Explanation - Beta suppression occurs when the brain transitions from alertness to drowsiness.
Correct answer is: A sudden reduction in beta band activity during drowsiness.
Q.61 Which of the following best explains why EMG recordings often require band‑pass filtering between 10–500 Hz?
To eliminate muscle noise.
To isolate the heart rate signal.
Because muscle action potentials contain most energy in this band.
To capture the alpha rhythm.
Explanation - EMG frequency content largely lies between 10–500 Hz; filtering reduces irrelevant components.
Correct answer is: Because muscle action potentials contain most energy in this band.
Q.62 Which of the following is a typical feature of a focal interictal epileptiform discharge on EEG?
Diffuse, bilateral 3–4 Hz spike‑and‑wave pattern.
Sharp wave or spike localized to one or a few electrodes.
High amplitude theta rhythm.
Beta bursts across all channels.
Explanation - Focal spikes are confined to a limited cortical region.
Correct answer is: Sharp wave or spike localized to one or a few electrodes.
Q.63 Which of the following best describes the term 'electroencephalogram (EEG) amplitude spectrum'?
The plot of EEG voltage over time.
The distribution of EEG power across different frequencies.
The electrode impedance values.
The phase relationship between electrodes.
Explanation - An amplitude spectrum shows how power is allocated among frequency components.
Correct answer is: The distribution of EEG power across different frequencies.
Q.64 Which of the following is the most common cause of 'flat line' in an EEG recording?
Excessive muscle activity.
Improper electrode contact.
High sampling rate.
Low‑pass filter saturation.
Explanation - Poor contact leads to no detectable electrical activity, yielding a flatline.
Correct answer is: Improper electrode contact.
Q.65 Which of the following best explains why a 32‑channel EEG is preferred for source localization over a 19‑channel EEG?
It uses fewer electrodes.
It allows higher sampling rates.
It provides better spatial resolution.
It is less expensive.
Explanation - More electrodes yield finer spatial sampling, improving source reconstruction accuracy.
Correct answer is: It provides better spatial resolution.
Q.66 Which of the following is a key component of the EMG signal that indicates the recruitment of motor units?
RMS amplitude increases.
Signal frequency decreases.
Phase shift increases.
Sampling rate increases.
Explanation - Increased RMS reflects activation of additional motor units during stronger contraction.
Correct answer is: RMS amplitude increases.
Q.67 Which of the following best describes the role of an EEG in diagnosing sleep‑disordered breathing?
Detecting respiratory muscle EMG bursts.
Measuring oxygen saturation.
Recording brain activity during apnea events.
Assessing heart rhythm during sleep.
Explanation - EEG helps determine arousal thresholds and central vs. obstructive events by monitoring brain waves.
Correct answer is: Recording brain activity during apnea events.
Q.68 Which of the following is a common technique used to remove ocular artifacts from EEG data?
Independent component analysis (ICA).
Band‑stop filtering at 60 Hz.
Amplitude thresholding.
Root‑mean‑square calculation.
Explanation - ICA can isolate components representing eye movements, which are then subtracted.
Correct answer is: Independent component analysis (ICA).
Q.69 Which of the following best describes the term 'burst suppression ratio' in an EEG?
The percentage of time the signal is above a certain amplitude.
The ratio of the number of bursts to the total recording time.
The proportion of suppressed periods relative to the entire recording.
The ratio of high‑frequency power to low‑frequency power.
Explanation - Burst suppression ratio quantifies how much of the EEG is in a flat or low‑activity state.
Correct answer is: The proportion of suppressed periods relative to the entire recording.
Q.70 Which of the following best explains the 'muscle artifact' seen in EEG recordings during a patient speaking?
Brain waves are suppressed.
Jaw muscles generate high‑frequency potentials that contaminate the EEG.
Power line interference increases.
Eye movement artifact increases.
Explanation - Speaking activates facial muscles, producing EMG signals that superimpose on the EEG.
Correct answer is: Jaw muscles generate high‑frequency potentials that contaminate the EEG.
Q.71 Which of the following is a typical EMG finding in myasthenia gravis during repetitive nerve stimulation?
Monophasic motor unit potentials.
Short latency reflexes.
Worsening of EMG amplitude with repeated stimulation.
Continuous high‑frequency bursts.
Explanation - Myasthenia gravis shows decremental responses during repetitive nerve stimulation.
Correct answer is: Worsening of EMG amplitude with repeated stimulation.
Q.72 Which of the following best describes a 'seizure focus' in EEG?
Area where high‑frequency activity originates during a seizure.
Region with the lowest amplitude activity.
The entire brain during a tonic‑clonic seizure.
Area that shows no activity during sleep.
Explanation - The seizure focus is the cortical region initiating abnormal electrical discharges.
Correct answer is: Area where high‑frequency activity originates during a seizure.
Q.73 Which of the following is a common feature of the EMG signal during a 'flickering' muscle contraction?
Constant amplitude.
Rapid, intermittent bursts of activity.
Slow sinusoidal pattern.
No detectable signal.
Explanation - Flickering represents a series of brief contractions, seen as bursts in EMG.
Correct answer is: Rapid, intermittent bursts of activity.
Q.74 Which of the following is a standard criterion for classifying an EEG as 'normal'?
Presence of 1–2 Hz delta waves.
Absence of epileptiform discharges and normal background rhythm.
Continuous slow‑wave activity.
Diffuse 3–4 Hz spike‑and‑wave pattern.
Explanation - A normal EEG shows typical background rhythms without abnormal spikes or waves.
Correct answer is: Absence of epileptiform discharges and normal background rhythm.
Q.75 Which of the following best describes the term 'signal‑to‑noise ratio' (SNR) in EMG?
Ratio of muscle force to EMG amplitude.
Ratio of signal power to background noise power.
Ratio of electrode impedance to skin resistance.
Ratio of sampling frequency to Nyquist frequency.
Explanation - SNR indicates how distinguishable the muscle signal is from noise.
Correct answer is: Ratio of signal power to background noise power.
Q.76 Which of the following best explains why the EEG is useful in monitoring brain function during anesthesia?
It detects cardiac output changes.
It measures muscle tone changes.
It records electrical activity, indicating depth of anesthesia.
It tracks blood glucose levels.
Explanation - EEG patterns such as burst suppression or alpha activity correlate with anesthetic depth.
Correct answer is: It records electrical activity, indicating depth of anesthesia.
Q.77 Which of the following best describes the 'myoelectric burst' phenomenon observed during sustained contraction?
A single, long‑duration action potential.
A rapid succession of action potentials from multiple motor units.
A continuous low‑frequency wave.
An isolated high‑amplitude spike.
Explanation - During sustained contraction, many motor units fire in bursts, creating a continuous EMG signal.
Correct answer is: A rapid succession of action potentials from multiple motor units.
Q.78 Which of the following is a typical cause of 'slow waves' in the EEG of an elderly patient?
Hypertensive crisis.
Chronic insomnia.
Generalized slowing due to metabolic encephalopathy.
Acute stroke.
Explanation - Slow waves often reflect diffuse cortical dysfunction, common in elderly metabolic states.
Correct answer is: Generalized slowing due to metabolic encephalopathy.
Q.79 Which of the following best describes the 'muscle artifact' in EEG that has a frequency of about 80–150 Hz?
Eye movement artifact.
Power line interference.
Facial muscle activity.
Cardiac artifact.
Explanation - Facial muscles generate EMG noise in this high‑frequency band, contaminating the EEG.
Correct answer is: Facial muscle activity.
Q.80 Which of the following is NOT a typical method for cleaning up EEG data?
Band‑pass filtering
Artifact rejection by thresholding
Increasing electrode impedance
Independent component analysis (ICA)
Explanation - Higher impedance degrades signal quality; cleaning aims to reduce impedance.
Correct answer is: Increasing electrode impedance
Q.81 Which of the following best describes the 'spectral power density' of an EMG signal?
The total number of spikes per second.
The distribution of EMG power over frequency components.
The amplitude of the largest peak.
The ratio of high to low frequencies.
Explanation - Spectral power density shows how EMG energy is spread across frequencies.
Correct answer is: The distribution of EMG power over frequency components.
Q.82 Which of the following best explains the clinical significance of an EEG showing a 'periodic lateralized epileptiform discharge (PLED) pattern'?
It indicates a normal sleep pattern.
It suggests an acute unilateral cortical abnormality.
It denotes chronic insomnia.
It is a marker of normal aging.
Explanation - PLEDs are often associated with acute lesions such as stroke or infection.
Correct answer is: It suggests an acute unilateral cortical abnormality.
Q.83 Which of the following best describes the 'focal motor seizure' as seen in an EEG?
Diffuse 3–4 Hz spike‑and‑wave activity.
Localized spike‑and‑wave activity restricted to one region.
High‑amplitude theta waves.
Beta bursts across the scalp.
Explanation - Focal seizures originate in a specific cortical area and produce localized EEG changes.
Correct answer is: Localized spike‑and‑wave activity restricted to one region.
Q.84 Which of the following is a major advantage of using high‑density EMG arrays?
Increased electrode impedance.
Reduced spatial resolution.
Detailed mapping of muscle activation patterns.
Simplified electrode placement.
Explanation - High‑density arrays provide fine spatial sampling of muscle activity.
Correct answer is: Detailed mapping of muscle activation patterns.
Q.85 Which of the following best explains why EEG electrodes are usually placed on the scalp?
The brain is directly connected to the scalp.
The scalp provides a convenient, non‑invasive interface to the underlying cortex.
The scalp can be used for stimulation.
The scalp amplifies neural signals.
Explanation - EEG electrodes detect electrical potentials generated by cortical neurons through the scalp.
Correct answer is: The scalp provides a convenient, non‑invasive interface to the underlying cortex.
Q.86 Which of the following best describes the 'focal slow wave' seen on EEG?
Diffuse low‑frequency activity over the entire scalp.
High‑amplitude slow wave restricted to a specific region.
Rapid 30‑Hz oscillations.
Alpha rhythm during eyes‑open rest.
Explanation - A focal slow wave indicates localized cortical dysfunction.
Correct answer is: High‑amplitude slow wave restricted to a specific region.
Q.87 Which of the following best explains why EMG is a useful tool in assessing peripheral nerve injuries?
It directly images nerve fibers.
It measures conduction velocity and muscle response.
It records cortical activity.
It monitors heart rate.
Explanation - EMG evaluates motor unit integrity and nerve conduction, crucial for nerve injury assessment.
Correct answer is: It measures conduction velocity and muscle response.
Q.88 Which of the following is the most common artifact seen in EEG recordings during sleep?
Power line noise at 60 Hz.
Eyelid blink artifact.
Muscle artifact from leg movements.
Respiratory artifact.
Explanation - Eyelid movements produce large potentials in the frontal electrodes during sleep.
Correct answer is: Eyelid blink artifact.
Q.89 Which of the following best describes the term 'neural noise' in the context of EEG?
Random fluctuations in the EEG signal unrelated to meaningful brain activity.
Noise from the patient's breathing.
Electrical interference from the power supply.
Artifacts from electrode movement.
Explanation - Neural noise refers to non‑cortical, random background fluctuations in the EEG.
Correct answer is: Random fluctuations in the EEG signal unrelated to meaningful brain activity.
Q.90 Which of the following best explains why the EMG signal of the biceps brachii shows a higher amplitude during a maximal voluntary contraction?
Because the skin is thicker over the biceps.
Because more motor units are recruited and fire at higher rates.
Because the electrode impedance decreases.
Because the sampling rate increases.
Explanation - Maximal contraction recruits the full motor unit pool, increasing EMG amplitude.
Correct answer is: Because more motor units are recruited and fire at higher rates.
Q.91 Which of the following best describes the 'EEG coherence' measure?
The similarity between EEG signals from different electrodes.
The absolute amplitude of the EEG signal.
The time delay between stimulus and response.
The ratio of high‑frequency to low‑frequency power.
Explanation - Coherence quantifies functional connectivity across brain regions.
Correct answer is: The similarity between EEG signals from different electrodes.
Q.92 Which of the following is a typical method for reducing EMG contamination in an EEG recording?
Increase electrode impedance.
Use a high‑pass filter at 0.1 Hz.
Use a notch filter at 50/60 Hz.
Use a band‑pass filter from 30–70 Hz.
Explanation - Notch filters eliminate power‑line interference, which can mimic EMG artifacts.
Correct answer is: Use a notch filter at 50/60 Hz.
Q.93 Which of the following best describes a 'seizure‑related muscle artifact' in EEG?
A high‑frequency EMG burst that coincides with a seizure onset.
A slow delta wave during REM sleep.
A flatline due to electrode failure.
A 3–4 Hz spike‑and‑wave pattern.
Explanation - Seizure‑related muscle artifacts arise from tonic muscle activity during seizures.
Correct answer is: A high‑frequency EMG burst that coincides with a seizure onset.
Q.94 Which of the following is the most reliable method for quantifying muscle fatigue from an EMG signal?
Decrease in the median frequency of the power spectrum.
Increase in the amplitude of the signal.
Decrease in sampling frequency.
Increase in electrode impedance.
Explanation - Fatigue often leads to a shift toward lower frequencies in the EMG spectrum.
Correct answer is: Decrease in the median frequency of the power spectrum.
Q.95 Which of the following best describes the term 'beta blocking' in an EEG during drowsiness?
An increase in beta activity.
A decrease in beta activity.
An appearance of theta waves.
An appearance of delta waves.
Explanation - Beta blocking occurs as alertness decreases and slower rhythms dominate.
Correct answer is: A decrease in beta activity.
Q.96 Which of the following best describes 'EMG‑driven prosthetic control'?
Using the EMG signal to trigger electrical stimulation of muscles.
Using EMG signals to encode prosthetic limb movements.
Using EMG signals to control a computer cursor only.
Using EMG to measure heart rate.
Explanation - EMG‑driven prosthetics interpret muscle signals to produce prosthesis motions.
Correct answer is: Using EMG signals to encode prosthetic limb movements.
Q.97 Which of the following is a characteristic of the EEG pattern seen in chronic insomnia?
Diffuse delta activity.
Alpha waves during eyes‑closed rest.
Increased theta and low‑beta activity.
Rapid 3–4 Hz spike‑and‑wave patterns.
Explanation - Insomnia often shows hyperactivity in theta/low‑beta ranges, indicating reduced sleep depth.
Correct answer is: Increased theta and low‑beta activity.
Q.98 Which of the following best explains why high‑pass filtering at 10 Hz is used in surface EMG recordings?
To remove power line interference.
To remove slow drift and movement artifacts.
To isolate the alpha rhythm.
To increase the signal amplitude.
Explanation - A 10 Hz high‑pass filter suppresses low‑frequency artifacts while preserving EMG content.
Correct answer is: To remove slow drift and movement artifacts.
Q.99 Which of the following is a typical feature of a 'periodic sharp wave' pattern in EEG?
Continuous high‑amplitude alpha rhythm.
Regularly spaced sharp waves at 1–2 Hz.
Diffuse low‑frequency slowing.
Sudden, short bursts of activity.
Explanation - Periodic sharp waves are seen in status epilepticus and other severe conditions.
Correct answer is: Regularly spaced sharp waves at 1–2 Hz.
Q.100 Which of the following best describes the 'median frequency shift' technique in EMG fatigue assessment?
A shift of the median frequency to higher values.
A shift of the median frequency to lower values.
No shift in the median frequency.
A shift in the amplitude of the median frequency.
Explanation - Fatigue causes a shift to lower frequencies as motor units fatigue and firing rates drop.
Correct answer is: A shift of the median frequency to lower values.
Q.101 Which of the following best describes a 'burst‑suppression pattern' in an EEG recorded during severe anoxic injury?
Continuous high‑frequency activity.
Alternating periods of high amplitude bursts and flat lines.
Diffuse slow‑wave activity.
Persistent 3–4 Hz spike‑and‑wave complexes.
Explanation - Burst‑suppression is a hallmark of deep coma or anoxic brain injury.
Correct answer is: Alternating periods of high amplitude bursts and flat lines.
Q.102 Which of the following best describes the 'low‑frequency' component of an EEG?
Activity below 0.5 Hz.
Activity between 4–8 Hz.
Activity between 8–13 Hz.
Activity above 30 Hz.
Explanation - Low‑frequency components include DC shifts and very slow drift potentials.
Correct answer is: Activity below 0.5 Hz.
Q.103 Which of the following is the most common cause of a sudden, high‑amplitude spike in the EEG of a patient with epilepsy?
Power line interference.
Eyelid blink artifact.
Inter‑ictal epileptiform discharge.
Motion artifact.
Explanation - Spike‑and‑wave complexes are typical of inter‑ictal activity in epileptic brains.
Correct answer is: Inter‑ictal epileptiform discharge.