CNIM Practice Exam

What are the two main ascending (sensory) pathways to understand for CNIM?

A) Anterior and lateral corticospinal tracts

B) Corticospinal and corticobulbar tracts

C) Dorsal column–medial lemniscus and spinothalamic tracts

D) Rubrospinal and reticulospinal tracts

C) Dorsal column–medial lemniscus and spinothalamic tracts

Mechanoreceptors respond to what, and what are the four types?

A) Pain and temperature (free nerve endings)

B) Proprioception only (muscle spindles, Golgi tendon organs)

C) Light and chemical stimuli (photoreceptors, chemoreceptors)

D) Touch, pressure, vibration, cutaneous tension (Meissner, Pacinian, Merkel, Ruffini)

D) Touch, pressure, vibration, cutaneous tension (Meissner, Pacinian, Merkel, Ruffini)

Where is the first-order neuron cell body of the dorsal column pathway, and what is its structure?

A) Anterior horn; multipolar

B) Dorsal root ganglion; pseudounipolar

C) Substantia gelatinosa; interneuron

D) Nucleus gracilis; bipolar

B) Dorsal root ganglion; pseudounipolar

In the dorsal column pathway, which fasciculus carries lower vs upper body input?

A) Both fasciculi carry upper-body input

B) Cuneate = lower; gracile = trunk

C) Gracile = lower; cuneate = upper

D) Gracile = upper; cuneate = lower

C) Gracile = lower; cuneate = upper

Where are the second-order neurons of the dorsal column pathway and where are they?

A) Dorsal root ganglion (intervertebral foramina)

B) Nucleus gracilis and nucleus cuneatus (medulla)

C) VPL of the thalamus (midbrain)

D) Substantia gelatinosa (dorsal horn)

B) Nucleus gracilis and nucleus cuneatus (medulla)

Where does the dorsal column pathway decussate, and what are the crossing fibers called?

A) Cord entry level; Lissauer's fibers

B) Midbrain; decussation of the pyramids

C) Medulla; internal arcuate fibers

D) Anterior white commissure; commissural fibers

C) Medulla; internal arcuate fibers

After decussation, what do internal arcuate fibers form and where do they terminate (3rd-order neuron)?

A) Spinothalamic tract; VPM of the thalamus

B) Lateral lemniscus; medial geniculate

C) Corona radiata; internal capsule

D) Medial lemniscus; VPL of the thalamus

D) Medial lemniscus; VPL of the thalamus

From the VPL, how do dorsal column fibers reach cortex?

A) Genu of internal capsule to cingulate gyrus

B) Posterior limb of internal capsule to corona radiata to postcentral gyrus

C) Medial lemniscus to inferior colliculus

D) Anterior limb of internal capsule to precentral gyrus

B) Posterior limb of internal capsule to corona radiata to postcentral gyrus

What does the lateral vs anterior spinothalamic tract carry?

A) Lateral = light touch; anterior = pain/temperature

B) Both tracts carry proprioception

C) Lateral = pain/temperature/coarse touch; anterior = light touch/pressure/itch

D) Lateral = vibration; anterior = pressure

C) Lateral = pain/temperature/coarse touch; anterior = light touch/pressure/itch

Where does the spinothalamic tract decussate?

A) Medulla, via internal arcuate fibers

B) Dorsal root entry zone

C) Midbrain

D) Anterior white commissure, near the level of entry

D) Anterior white commissure, near the level of entry

Where are the second-order neurons of the spinothalamic pathway?

A) VPL of the thalamus

B) Dorsal horn (substantia gelatinosa of Rolando / nucleus proprius)

C) Nucleus gracilis and cuneatus

D) Anterior horn cells

B) Dorsal horn (substantia gelatinosa of Rolando / nucleus proprius)

Where does the corticospinal pathway begin?

A) Anterior horn of the cord

B) Post-central gyrus (somatosensory cortex)

C) Supplementary motor area only

D) Pre-central gyrus (primary motor cortex)

D) Pre-central gyrus (primary motor cortex)

Where does the corticospinal tract decussate, and what is it called?

A) Cord entry; internal arcuate decussation

B) Midbrain; decussation of Meynert

C) Caudal medulla–cord junction; decussation of the pyramids

D) Anterior white commissure; decussation of Forel

C) Caudal medulla–cord junction; decussation of the pyramids

Lateral vs anterior corticospinal tract — which has already decussated?

A) Anterior already decussated; lateral at its target level

B) Neither tract decussates

C) Lateral already decussated (medulla); anterior decussates at its target level

D) Both decussate in the medulla

C) Lateral already decussated (medulla); anterior decussates at its target level

Define upper vs lower motor neurons in the corticospinal path.

A) UMN = anterior horn to muscle; LMN = cortex to horn

B) Both originate in the thalamus

C) UMN = DRG to cord; LMN = cord to skin

D) UMN = cortex to anterior horn; LMN = anterior horn to muscle

D) UMN = cortex to anterior horn; LMN = anterior horn to muscle

How many spinal nerve roots are there, and how are they distributed?

A) 31: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal

B) 33: 8C, 12T, 5L, 5S, 3 coccygeal

C) 30: 7C, 12T, 5L, 5S, 1 coccygeal

D) 31: 7C, 12T, 5L, 5S, 2 coccygeal

A) 31: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal

What is the purpose of the popliteal fossa (PF) recording?

A) Confirm nerve stimulation and identify peripheral nerve changes (ischemia, temperature)

B) Directly measure central conduction time

C) Record cortical somatosensory activity

D) Confirm conduction across the thoracic cord

A) Confirm nerve stimulation and identify peripheral nerve changes (ischemia, temperature)

What generates the lumbar potential (LP) and where is it recorded?

A) Caudal medial lemniscus; scalp

B) Spinal cord; recorded ~T12 (post-synaptic activity)

C) Brachial plexus; Erb's point

D) Nucleus cuneatus; C5

B) Spinal cord; recorded ~T12 (post-synaptic activity)

Generators of P31 and N34 (lower-limb SSEP)?

A) P31 = thalamus; N34 = medial lemniscus

B) P31 = caudal medial lemniscus; N34 = upper brainstem/thalamus

C) P31 = cervical cord; N34 = pons

D) P31 = cortex; N34 = cerebellum

B) P31 = caudal medial lemniscus; N34 = upper brainstem/thalamus

Why are P31/N34 absent in a Cpz–Fz montage?

A) They require a higher stimulus intensity

B) They are near-field and too small to see

C) They fall outside the analysis window

D) They are far-field and cancelled by the scalp-scalp montage (common mode rejection)

D) They are far-field and cancelled by the scalp-scalp montage (common mode rejection)

What generates the PTN cortical potentials P37/N45?

A) Somatosensory cortex, contralateral medial post-central gyrus

B) Caudal medial lemniscus

C) Ipsilateral pre-central gyrus

D) Lumbar spinal cord

A) Somatosensory cortex, contralateral medial post-central gyrus

Paradoxical lateralization changes the PTN montage how?

A) Record from Cpc (dipole points contralateral)

B) Record from Cpi (dipole points ipsilateral); use two channels

C) Use a single midline channel

D) Record from Fz only

B) Record from Cpi (dipole points ipsilateral); use two channels

Which lower-limb SSEP peaks are obligate?

A) N34, P37, and N45

B) P31, N34, and P37

C) LP, P31, and N45

D) LP, N34, and P37 (P31 is not obligate)

D) LP, N34, and P37 (P31 is not obligate)

What does Erb's point record, and what montage is recommended?

A) Cortical potential; Cpc–Cpi

B) Brachial plexus CNAP (N9); montage EPi–EPc

C) Medial lemniscus; Fpz–reference

D) Cervical cord potential; C5S–Fz

B) Brachial plexus CNAP (N9); montage EPi–EPc

Generators of N13, P14, and N18 (upper-limb SSEP)?

A) N13 = cuneate nucleus; P14 = thalamus; N18 = pons only

B) N13 = cervical cord; P14 = caudal medial lemniscus; N18 = upper brainstem/thalamus

C) N13 = brachial plexus; P14 = cortex; N18 = cerebellum

D) N13 = cortex; P14 = cervical cord; N18 = medulla

B) N13 = cervical cord; P14 = caudal medial lemniscus; N18 = upper brainstem/thalamus

What does cortical N20 reflect, and how is it recorded?

A) Brachial plexus; near-field recording

B) Brainstem; scalp–non-cephalic reference

C) Thalamus; monopolar montage

D) Primary somatosensory cortex; bipolar scalp-scalp montage

D) Primary somatosensory cortex; bipolar scalp-scalp montage

Which SSEP peaks are considered far-field?

A) P14, N18 (upper) and P31, N34 (lower)

B) N20 and P37

C) Erb's point and N9

D) N13 and LP

A) P14, N18 (upper) and P31, N34 (lower)

N13 — what is it, and how does its polarity behave?

A) Stationary cervical (cervicomedullary) potential; horizontal dipole (posterior neck negative)

B) Propagated cortical potential; vertical dipole

C) Far-field brainstem potential; radial dipole

D) Peripheral nerve potential; no dipole

A) Stationary cervical (cervicomedullary) potential; horizontal dipole (posterior neck negative)

Central conduction time (CCT) for the median nerve, and how it's measured?

A) P14–N20 = 15 ms

B) N20–P37 = 6 ms

C) LP–P37 = 6 ms

D) P14–N20 = 6 ms

D) P14–N20 = 6 ms

CCT for the PTN, and how it's measured?

A) LP–P37 = 6 ms

B) LP–P37 = 15 ms

C) P14–N20 = 15 ms

D) N34–P37 = 15 ms

B) LP–P37 = 15 ms

Upper-to-lower SSEP peak analogues?

A) N13 ~ N34; P14 ~ P37

B) P14 ~ N34; N18 ~ P31

C) N20 ~ P37; P14 ~ LP

D) P14 ~ P31; N18 ~ N34

D) P14 ~ P31; N18 ~ N34

On the CNIM, are upward-deflecting peaks positive or negative in the guideline montages?

A) Upward = negative; downward = positive

B) Both upward and downward = negative

C) Upward = positive; downward = negative

D) It depends on the gain setting

A) Upward = negative; downward = positive

Where is the ground electrode placed for clinical SSEP, and why?

A) Over the recording site, to lower impedance

B) On the scalp near Fz, to reduce EEG

C) On the stimulated limb, to reduce stimulus artifact

D) On the contralateral limb

C) On the stimulated limb, to reduce stimulus artifact

What SSEP electrode impedance should be maintained?

A) < 100 Ω

B) 10–50 kΩ

C) < 5 kΩ

D) < 5 MΩ

C) < 5 kΩ

Depolarization vs hyperpolarization — under the cathode or anode?

A) Depolarization under the anode; hyperpolarization under the cathode

B) Both occur under the cathode

C) Depolarization under the cathode; hyperpolarization under the anode

D) Neither depends on electrode polarity

C) Depolarization under the cathode; hyperpolarization under the anode

Blood supply relevant to upper- vs lower-limb SSEP peaks?

A) Upper: ACA only; Lower: MCA only

B) Both supplied solely by the basilar artery

C) Upper: MCA, basilar, spinal, subclavian; Lower: ACA, basilar, spinal

D) Upper: PCA; Lower: PICA

C) Upper: MCA, basilar, spinal, subclavian; Lower: ACA, basilar, spinal

At what velocity do myelinated fibers conduct, and what changes it?

A) 50–60 m/s; myelination and larger fibers increase, demyelination slows

B) 100–120 m/s; slowed by warming

C) 5–10 m/s; unaffected by myelination

D) 20–30 m/s; increased by cooling

A) 50–60 m/s; myelination and larger fibers increase, demyelination slows

Orthodromic vs antidromic conduction?

A) Both mean afferent conduction

B) Orthodromic = opposite; antidromic = normal

C) Both mean efferent conduction

D) Orthodromic = normal physiologic direction; antidromic = opposite

D) Orthodromic = normal physiologic direction; antidromic = opposite

ACNS SSEP stimulation: pulse duration and repetition rate?

A) 100–300 µs; clinical 3–5 Hz (IOM up to ~8–20 Hz)

B) 1–2 ms; 50–60 Hz

C) 10–50 µs; 0.5–1 Hz

D) 500–1000 µs; 2 Hz

A) 100–300 µs; clinical 3–5 Hz (IOM up to ~8–20 Hz)

ACNS cortical SSEP filter bandpass?

A) ~1–30 Hz to 250–3000 Hz

B) 0.1–1 Hz to 100 Hz

C) 10–30 Hz to 2500–3000 Hz

D) 100–200 Hz to 1000–3000 Hz

A) ~1–30 Hz to 250–3000 Hz

ACNS spinal-cord SSEP filter bandpass?

A) 100–200 Hz to 1000–3000 Hz

B) 0.5–5 Hz to 100 Hz

C) 1–30 Hz to 250–3000 Hz

D) 10–100 Hz to 10 kHz

A) 100–200 Hz to 1000–3000 Hz

SSEP analysis time — cervical vs thoracolumbar?

A) Both 500 ms

B) Cervical 75–150 ms; thoracolumbar 30–100 ms

C) Cervical 30–100 ms; thoracolumbar 75–150 ms

D) Cervical 10–15 ms; thoracolumbar 30–50 ms

C) Cervical 30–100 ms; thoracolumbar 75–150 ms

SSEP number of averages — cervical vs thoracolumbar?

A) Cervical 1000–3000; thoracolumbar 500–2000

B) Both 100

C) Cervical 500–2000; thoracolumbar 1000–3000

D) Cervical 50–100; thoracolumbar 100–300

C) Cervical 500–2000; thoracolumbar 1000–3000

For the differential amplifier, do we want high or low input impedance?

A) Equal to electrode impedance

B) Zero (grounded)

C) High — at least 100 MΩ

D) Low — 5 kΩ or less

C) High — at least 100 MΩ

Analog vs digital filters — the key difference in phase effects?

A) Analog has phase effects (pre-digitization); digital has none (post-A/D, reversible)

B) Neither has phase effects

C) Both are irreversible

D) Digital has phase effects; analog has none

A) Analog has phase effects (pre-digitization); digital has none (post-A/D, reversible)

Low frequency filter — other names and function?

A) Notch; removes 60 Hz

B) Hicut / low-pass; attenuates fast waves

C) Band-stop; removes the midband

D) Locut / high-pass; attenuates slow (low-frequency) waves

D) Locut / high-pass; attenuates slow (low-frequency) waves

High frequency filter — other names and function?

A) Hicut / low-pass; attenuates fast (high-frequency) waves

B) Locut / high-pass; attenuates slow waves

C) All-pass; no attenuation

D) Notch; removes 60 Hz

A) Hicut / low-pass; attenuates fast (high-frequency) waves

What is the notch filter for, and why avoid it in SSEP/T-EMG?

A) DC drift; avoided because it clips signals

B) 60 Hz; avoided due to a ringing artifact with transients (distorts the response)

C) 120 Hz; avoided because it only adds latency

D) 50 Hz; avoided because it raises impedance

B) 60 Hz; avoided due to a ringing artifact with transients (distorts the response)

Why are filters used?

A) To improve the signal-to-noise ratio (attenuate noise, keep the band of interest)

B) To increase stimulus intensity

C) To amplify all frequencies equally

D) To convert analog to digital

A) To improve the signal-to-noise ratio (attenuate noise, keep the band of interest)

Effect of increasing the locut (high-pass) filter on an SSEP peak?

A) Shifts the peak left (earlier latency) and attenuates amplitude

B) No latency change; increases amplitude

C) Shifts the peak right and increases amplitude

D) Shifts the peak left and increases amplitude

A) Shifts the peak left (earlier latency) and attenuates amplitude

Effect of decreasing the hicut (low-pass) filter on an SSEP peak?

A) No effect on latency

B) Shifts the peak right and increases amplitude

C) Shifts the peak left and attenuates amplitude

D) Shifts the peak right (later latency) and attenuates amplitude

D) Shifts the peak right (later latency) and attenuates amplitude

What is bandpass?

A) The 60 Hz notch region

B) The amplifier's dynamic range

C) The sampling frequency range

D) The frequency range between the low- and high-frequency cutoffs

D) The frequency range between the low- and high-frequency cutoffs

Define cutoff frequency and the -3 dB point.

A) The full-power point (100%)

B) Where energy begins to attenuate; -3 dB = half power (~70.71% voltage)

C) The zero-crossing of the waveform

D) Where energy doubles; +3 dB = double power

B) Where energy begins to attenuate; -3 dB = half power (~70.71% voltage)

What is roll-off, and its units?

A) The amplifier's gain; dB only

B) The sampling interval; µs

C) The filter's center frequency; Hz

D) Steepness of attenuation outside the cutoff; dB/decade or dB/octave

D) Steepness of attenuation outside the cutoff; dB/decade or dB/octave

20 dB/decade equals how many dB/octave?

A) About 20 dB/octave

B) About 3 dB/octave

C) About 12 dB/octave

D) About 6 dB/octave

D) About 6 dB/octave

Frequency formula and the definition of Hz?

A) Frequency = 1/amplitude

B) Frequency = period / 2

C) Frequency = period × cycles

D) Frequency = 1/period (Hz = cycles per second)

D) Frequency = 1/period (Hz = cycles per second)

What is the period of a 60 Hz signal?

A) 6 ms

B) 60 ms

C) 1.67 ms

D) 16.7 ms

D) 16.7 ms

You see 12 cycles of a repeating wave in a 100 ms sweep — what frequency?

A) 120 Hz

B) 60 Hz

C) 1200 Hz

D) 12 Hz

A) 120 Hz

What determines horizontal resolution?

A) The sampling frequency (points per second)

B) The number of bits

C) The filter bandpass

D) The amplifier gain

A) The sampling frequency (points per second)

ACNS maximum bin width and corresponding minimum sampling frequency?

A) 20 ms/point, so 50 Hz

B) 2 µs/point, so 500 kHz

C) 20 µs/point, so at least 50 kHz

D) 100 µs/point, so 10 kHz

C) 20 µs/point, so at least 50 kHz

Sampling frequency with a dwell time (bin width) of 10 µs?

A) 100 kHz

B) 1 MHz

C) 10 kHz

D) 50 kHz

A) 100 kHz

What is aliasing, and when does it occur?

A) Baseline drift from a DC offset

B) An erroneous signal from under-sampling below the Nyquist frequency

C) Signal clipping when above the dynamic range

D) Ringing from a notch filter

B) An erroneous signal from under-sampling below the Nyquist frequency

State the Nyquist theorem.

A) Sample at exactly the highest frequency

B) Sample at ten times the highest frequency

C) Sample at at least twice the highest frequency being recorded

D) Sample at at least half the highest frequency

C) Sample at at least twice the highest frequency being recorded

If the highest EP frequency is 2000 Hz, what sampling rate is required?

A) 8000 Hz

B) 4000 Hz

C) 1000 Hz

D) 2000 Hz

B) 4000 Hz

What determines vertical resolution?

A) The dwell time

B) The sampling frequency

C) The filter roll-off

D) Number of bits (2^N); at least 8 bits (256 values)

D) Number of bits (2^N); at least 8 bits (256 values)

What is dynamic range?

A) The electrode impedance window

B) The voltage range the A/D can represent; outside it, signals are lost or clipped

C) The number of trials averaged

D) The frequency range passed by the filters

B) The voltage range the A/D can represent; outside it, signals are lost or clipped

How does noise change with averaging?

A) Noise falls linearly with N; double to halve

B) Noise falls by the square root of N; quadruple the averages to halve noise

C) Averaging does not change noise

D) Noise falls by N squared; halve to halve

B) Noise falls by the square root of N; quadruple the averages to halve noise

SNR is 2:1 after 100 averages — how many averages are needed for SNR = 5?

A) 625

B) 250

C) 500

D) 2500

A) 625

Background noise is 5 µV — what is it after 400 averages?

A) 1.25 µV

B) 0.25 µV

C) 2.5 µV

D) 0.0125 µV

B) 0.25 µV

Define bandpass, sampling rate, and dwell time.

A) Bandpass = gain; sampling rate = bits; dwell = averages

B) Bandpass = passed band; sampling rate = samples/sec; dwell = time per sample

C) All three equal the analysis time

D) Bandpass = notch; sampling rate = sweep; dwell = trials

B) Bandpass = passed band; sampling rate = samples/sec; dwell = time per sample

Define epoch (sweep) and trials.

A) Epoch = bandpass; trials = gain

B) Epoch = dwell time; trials = bits

C) Epoch = total raw data length averaged; trials = number of stimulus/recording samples

D) Epoch = one sample point; trials = a filter setting

C) Epoch = total raw data length averaged; trials = number of stimulus/recording samples

Gain vs sensitivity?

A) Gain = impedance; sensitivity = filter

B) They are identical

C) Gain = signal amplification (sensitivity is a display parameter)

D) Gain = display scale; sensitivity = amplification

C) Gain = signal amplification (sensitivity is a display parameter)

Central auditory pathway mnemonic (AC-SLIM)?

A) Auditory nerve, Cochlear nucleus, Substantia nigra, Lateral lemniscus, Inferior colliculus, Medial lemniscus

B) Auditory nerve, Cochlear nucleus, Superior olivary complex, Lateral lemniscus, Inferior colliculus, Medial geniculate

C) Cochlea, Vestibular nucleus, Pons, Midbrain, Thalamus, Cortex

D) Auditory nerve, Cuneate nucleus, Superior colliculus, Lateral lemniscus, Inferior olive, Medial geniculate

B) Auditory nerve, Cochlear nucleus, Superior olivary complex, Lateral lemniscus, Inferior colliculus, Medial geniculate

BSER Wave I generator?

A) Inferior colliculus

B) Superior olivary complex

C) Cochlear nucleus (medulla)

D) Distal CN VIII as it leaves the cochlea

D) Distal CN VIII as it leaves the cochlea

BSER Wave II generator?

A) Lateral lemniscus

B) Distal CN VIII

C) Cochlear nucleus (medulla)

D) Inferior colliculus

C) Cochlear nucleus (medulla)

BSER Wave III generator?

A) Superior olivary complex (contralateral lower pons)

B) Inferior colliculus (midbrain)

C) Cochlear nucleus (medulla)

D) Distal CN VIII

A) Superior olivary complex (contralateral lower pons)

BSER Wave IV generator?

A) Medial geniculate

B) Distal CN VIII

C) Distal lateral lemniscus (pons)

D) Cochlear nucleus

C) Distal lateral lemniscus (pons)

BSER Wave V generator?

A) Medial geniculate (thalamus)

B) Superior olivary complex (pons)

C) Cochlear nucleus (medulla)

D) Inferior colliculus (midbrain)

D) Inferior colliculus (midbrain)

Obligate BAEP peaks and their normal adult latencies?

A) I = 2.7, III = 4.9, V = 6.7 ms

B) Wave I = 1.7 ms, III = 3.9 ms, V = 5.7 ms

C) I = 1.7, III = 5.7, V = 3.9 ms

D) I = 1.0, III = 3.0, V = 5.0 ms

B) Wave I = 1.7 ms, III = 3.9 ms, V = 5.7 ms

Where are the BSER generators located within the brainstem overall?

A) Medulla only

B) Lower pons to lower midbrain (III pons, V midbrain)

C) Thalamus and cortex

D) Cerebellum

B) Lower pons to lower midbrain (III pons, V midbrain)

What is Wave I also known as?

A) N1 / cochlear action potential (CAP)

B) Summating potential (SP)

C) Cochlear microphonic (CM)

D) Post-auricular muscle reflex (PAM)

A) N1 / cochlear action potential (CAP)

Standard BAEP recording montage?

A) Cz-Oz and Fz-Pz

B) Erb's–Cz bilaterally

C) C3-C4 and Fpz-Cz

D) A1-Cz and A2-Cz (M1/M2-Cz); EAM–Aipsi enhances Wave I

D) A1-Cz and A2-Cz (M1/M2-Cz); EAM–Aipsi enhances Wave I

BAEP stimulus type and intensity?

A) Tone burst, 1 ms; 40 dB HL

B) Broad-band click, 100 µs; 100 dB peSPL or 60–70 dB HL

C) Broad-band click; 20 dB SL

D) Click; 130 dB SPL

B) Broad-band click, 100 µs; 100 dB peSPL or 60–70 dB HL

BAEP contralateral masking value and purpose?

A) 10 dB HL to reduce artifact

B) 100 dB SPL to boost Wave I

C) 60 dB SPL (30–35 dB HL) to prevent crossover

D) No masking is used

C) 60 dB SPL (30–35 dB HL) to prevent crossover

BAEP repetition rate — clinical vs intraoperative?

A) 3–5 Hz clinical; 20 Hz intraop

B) 0.5–1 Hz clinical; 5 Hz intraop

C) 5–12 Hz clinical; up to 50 Hz intraoperative

D) 30 Hz clinical; 100 Hz intraop

C) 5–12 Hz clinical; up to 50 Hz intraoperative

BAEP filter bandpass — clinical vs IOM?

A) 0.5–5 Hz to 100 Hz for both

B) Clinical 10–30 Hz to 2500–3000 Hz; IOM 100–150 Hz to 2500–3000 Hz

C) Clinical 1–30 Hz to 250–3000 Hz

D) 100 Hz to 10 kHz for both

B) Clinical 10–30 Hz to 2500–3000 Hz; IOM 100–150 Hz to 2500–3000 Hz

BAEP sweep length and number of trials?

A) Sweep 50 ms; 10,000 trials

B) Sweep 5 ms; 50 trials

C) Sweep 10–15 ms; 1000–4000 trials

D) Sweep 100 ms; 500 trials

C) Sweep 10–15 ms; 1000–4000 trials

Cochlear microphonic — source, AC/DC, polarity dependence?

A) Auditory nerve; AC; independent of polarity

B) Hair cells; DC potential; independent of polarity

C) Cochlear nucleus; DC; polarity-dependent

D) Hair cells; AC potential; dependent on click polarity

D) Hair cells; AC potential; dependent on click polarity

Summating potential — source, AC/DC, polarity?

A) Hair cells; DC potential; independent of click polarity

B) Inferior colliculus; AC; independent

C) Auditory nerve; DC; dependent on polarity

D) Hair cells; AC; dependent on polarity

A) Hair cells; DC potential; independent of click polarity

What eliminates the cochlear microphonic?

A) Rarefaction clicks

B) Increasing stimulus intensity

C) Alternating clicks

D) Condensation clicks

C) Alternating clicks

What is PAM, and where/when does it appear?

A) A cortical response at 20 ms

B) Wave VI of the BAEP

C) A stimulus artifact at 0–2 ms

D) Post-auricular muscle reflex; triphasic ~12–20 ms

D) Post-auricular muscle reflex; triphasic ~12–20 ms

On CNIM, the downward potential at ~12 ms after stimulation is?

A) Cochlear microphonic

B) Post-auricular muscle reflex (PAM)

C) Summating potential

D) Wave V

B) Post-auricular muscle reflex (PAM)

Effect of condensation clicks?

A) Cancels the cochlear microphonic

B) No effect on latency

C) Larger Wave V; longer Wave I latency

D) Larger Wave I; shorter Wave I latency

C) Larger Wave V; longer Wave I latency

Effect of rarefaction clicks?

A) Reduces stimulus artifact

B) Larger Wave I; shorter Wave I latency

C) Eliminates the summating potential

D) Larger Wave V; longer Wave I latency

B) Larger Wave I; shorter Wave I latency

Effect of alternating clicks?

A) Reduce stimulus artifact and cancel the cochlear microphonic

B) Enhance the cochlear microphonic

C) Increase Wave V amplitude only

D) Prolong all latencies

A) Reduce stimulus artifact and cancel the cochlear microphonic

As stimulus intensity decreases, which BAEP wave attenuates last?

A) Wave III

B) All waves attenuate equally

C) Wave V (no interpeak latency change)

D) Wave I (with interpeak change)

C) Wave V (no interpeak latency change)

Effect of conductive hearing loss on BAEP interpeak intervals?

A) No interpeak change; absolute latencies shift outward symmetrically

B) Increased interpeak intervals

C) Abolishes Wave V only

D) Shortens all latencies

A) No interpeak change; absolute latencies shift outward symmetrically

What causes an increased Wave I latency?

A) Cortical injury

B) Conductive loss, fluid/wax, decreased intensity, transducer/tubing issues

C) Brainstem ischemia between III and V

D) Cerebellar retraction

B) Conductive loss, fluid/wax, decreased intensity, transducer/tubing issues

Effect of mild-to-moderate high-frequency (sensorineural) hearing loss on Wave I and the I–V interval?

A) Abolished Wave I

B) No change to any wave

C) Prolonged Wave V, giving a longer I–V interval

D) Prolonged Wave I, giving a shorter I–V interval

D) Prolonged Wave I, giving a shorter I–V interval

Cochlear (sensorineural) hearing loss — what is affected?

A) Middle-ear conduction problem; normal interpeaks

B) Nerve compression; prolonged III–V

C) Brainstem lesion; contralateral Wave V loss

D) Hair-cell loss; high-frequency; severe may abolish the BAEP or need higher intensity

D) Hair-cell loss; high-frequency; severe may abolish the BAEP or need higher intensity