Page 1 of 154
Clinical Neurophysiology (Oxford Specialist
Handbooks in Neurology) 2026.
Q1. In a clinical neurophysiology recording, what is the primary
function of a differential amplifier?
A) To increase the amplitude of the signal from a single
electrode
B) To subtract the signal at the reference electrode from the
signal at the active electrode
C) To filter out all frequencies above 50 Hz
D) To convert analog signals to digital
Answer: B
Rationale: A differential amplifier amplifies the difference
between two input signals (active and reference) while rejecting
signals that are common to both (common-mode rejection). This is
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essential for reducing noise and recording small
neurophysiological signals.
Q2. The 10-20 International System for EEG electrode
placement is based on measurements between which two skull
landmarks?
A) Nasion and inion
B) Tragus and mastoid
C) Vertex and pre-auricular points
D) Glabella and opisthion
Answer: A
Rationale: The nasion (bridge of nose) and inion (external
occipital protuberance) are the anterior and posterior midline
landmarks. The distance between them is divided into 10% and
20% intervals to locate electrodes.
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Q3. A patient has a cold limb during a nerve conduction study.
The recorded nerve conduction velocity will be:
A) Unchanged
B) Increased by approximately 2 m/s per 1°C drop
C) Decreased by approximately 1.5–2.5 m/s per 1°C drop
D) Decreased by 10 m/s per 1°C drop
Answer: C
Rationale: Temperature has a major effect on nerve conduction.
Cooling slows the opening of sodium channels, reducing
conduction velocity by about 1.5–2.5 m/s for each 1°C below
34°C. This is a common source of error.
Q4. (Scenario) A neurophysiology trainee is setting up for a
median nerve motor study. Where should the active (E1)
recording electrode be placed?
A) Over the thenar eminence, 2 cm distal to the wrist crease
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B) Over the belly of the abductor pollicis brevis muscle
C) Over the tendon of the flexor pollicis longus at the thumb
interphalangeal joint
D) Over the anatomical snuffbox
Answer: B
Rationale: For a median motor study, the active electrode (E1) is
placed over the motor point of the abductor pollicis brevis (APB)
muscle – approximately the midpoint of the thenar eminence. The
reference (E2) is placed over the thumb metacarpophalangeal
joint (tendon). This belly-tendon arrangement maximises the
compound muscle action potential (CMAP).
Q5. What is the typical electrode impedance range for a routine
EEG recording?
A) < 1 kΩ
B) < 5 kΩ
Clinical Neurophysiology (Oxford Specialist
Handbooks in Neurology) 2026.
Q1. In a clinical neurophysiology recording, what is the primary
function of a differential amplifier?
A) To increase the amplitude of the signal from a single
electrode
B) To subtract the signal at the reference electrode from the
signal at the active electrode
C) To filter out all frequencies above 50 Hz
D) To convert analog signals to digital
Answer: B
Rationale: A differential amplifier amplifies the difference
between two input signals (active and reference) while rejecting
signals that are common to both (common-mode rejection). This is
,Page 2 of 154
essential for reducing noise and recording small
neurophysiological signals.
Q2. The 10-20 International System for EEG electrode
placement is based on measurements between which two skull
landmarks?
A) Nasion and inion
B) Tragus and mastoid
C) Vertex and pre-auricular points
D) Glabella and opisthion
Answer: A
Rationale: The nasion (bridge of nose) and inion (external
occipital protuberance) are the anterior and posterior midline
landmarks. The distance between them is divided into 10% and
20% intervals to locate electrodes.
,Page 3 of 154
Q3. A patient has a cold limb during a nerve conduction study.
The recorded nerve conduction velocity will be:
A) Unchanged
B) Increased by approximately 2 m/s per 1°C drop
C) Decreased by approximately 1.5–2.5 m/s per 1°C drop
D) Decreased by 10 m/s per 1°C drop
Answer: C
Rationale: Temperature has a major effect on nerve conduction.
Cooling slows the opening of sodium channels, reducing
conduction velocity by about 1.5–2.5 m/s for each 1°C below
34°C. This is a common source of error.
Q4. (Scenario) A neurophysiology trainee is setting up for a
median nerve motor study. Where should the active (E1)
recording electrode be placed?
A) Over the thenar eminence, 2 cm distal to the wrist crease
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B) Over the belly of the abductor pollicis brevis muscle
C) Over the tendon of the flexor pollicis longus at the thumb
interphalangeal joint
D) Over the anatomical snuffbox
Answer: B
Rationale: For a median motor study, the active electrode (E1) is
placed over the motor point of the abductor pollicis brevis (APB)
muscle – approximately the midpoint of the thenar eminence. The
reference (E2) is placed over the thumb metacarpophalangeal
joint (tendon). This belly-tendon arrangement maximises the
compound muscle action potential (CMAP).
Q5. What is the typical electrode impedance range for a routine
EEG recording?
A) < 1 kΩ
B) < 5 kΩ
