WorksheetsEMG SAE (2020)
Total questions: 84
Worksheet time: 1hrs 3mins
Name
Class
Date
1.
A post-fixed brachial plexus has contributions primarily from the root levels of:
a)
C2-C6.
b)
C3-C7.
c)
C4-C8.
d)
C5-T1.
e)
C6-T2.
2.
Which one of the following best describes fasciculation potentials?
a)
Rapidly firing, high-amplitude, polyphasic motor unit action potentials (MUAPs).
b)
Trains of motor unit potentials under voluntary control.
c)
Spontaneous, irregular firing of MUAPs.
d)
Semirhythmic grouped discharges.
e)
Rhythmic firing of single muscle fibers.
3.
A 28-year-old tennis player complains of pain and weakness in the forearm. Sensation in the hand is normal, but there is weakness of interphalangeal flexion of the thumb. The median-to-index finger sensory response is normal. Needle electromyography (EMG) of the abductor pollicis brevis is normal. What should be done next?
a)
Diagnose mild carpal tunnel syndrome.
b)
Diagnose thoracic outlet syndrome with neurapraxia.
c)
Perform a needle EMG examination of the extensor indicus and paraspinal muscles.
d)
Perform a needle EMG examination of the flexor pollicis longus and pronator quadratus muscles.
e)
Perform an ulnar motor study.
4.
Which is the most critical factor listed in assessing heart rate variability during cyclic deep breathing?
a)
Age.
b)
Height.
c)
Core body temperature.
d)
Calculation used or statistical method.
e)
Gender.
5.
Which muscle listed is most clinically useful for a needle electromyography examination in a patient with hoarseness?
a)
Mylohyoid.
b)
Genioglossus.
c)
Cricothyroid.
d)
Lateral pterygoid.
e)
Thyrohyoid.
6.
When the sweep speed set at 10 ms/div and 10 div on the screen, a single voluntary motor unit action potential (MUAP) appears once per sweep on the screen. The MUAP slowly moves toward the right with each sweep. What is the frequency of the MUAP?
a)
1 Hz.
b)
8 Hz.
c)
10 Hz.
d)
12 Hz.
e)
20 Hz.
7.
What is a miniature endplate potential?
a)
The response of an individual muscle fiber to acute denervation.
b)
The presynaptic axon terminal response to near depletion of acetylcholine.
c)
The response of the endplate to full nerve terminal depolarization.
d)
The endplate response to the spontaneous release of acetylcholine.
e)
The depolarization of the entire motor unit.
8.
A 45-year-old man presents with tingling in the middle and index fingers of the right hand. Nerve conduction studies are normal. Needle electromyography (EMG) in the triceps and pronator teres show fibrillation potentials and reduced recruitment. Needle EMG in the biceps, deltoid, and first dorsal interosseous muscles are normal. Where is the lesion?
a)
C8 nerve root.
b)
Radial nerve at the spiral groove.
c)
Median nerve at the wrist.
d)
C7 nerve root.
e)
Middle trunk of the brachial plexus.
9.
During muscle contraction, the formation of the bridges between the actin and myosin depends on:
a)
Sodium (Na).
b)
Potassium (K).
c)
Calcium (Ca).
d)
Chlorine (Cl).
e)
Magnesium (Mg).
10.
Following 1 minute of contraction during needle electromyography of the gastrocnemius, there is an abrupt onset of a large number of potentials firing at 50 Hz for 20 seconds; just before termination they fire irregularly. This most likely represents:
a)
Cramp potentials.
b)
Complex repetitive discharges.
c)
Myokymic discharges.
d)
Fasciculation potentials.
e)
Neuromyotonia.
11.
A 65-year-old male presents with a 3-year history of progressive muscle weakness. Examination shows weakness of the deep finger flexors, quadriceps, and ankle dorsiflexors. His creatine kinase is elevated to 900 U/L. Muscle biopsy of the left quadriceps is most likely to show which of the following pathological findings?
a)
Angular muscle fibers with fiber type grouping.
b)
Enlarged capillaries with complement deposited in capillary walls adjacent to myofibers.
c)
Perifascicular atrophy with tubuloreticular inclusions in endothelial walls on electron microscopy.
d)
Muscle fibers with rimmed vacuoles with amyloid deposition and increased COX negative fibers.
e)
Ragged red fibers.
12.
While your patient gradually increases the voluntary tension in the muscle undergoing testing, you notice that the early motor unit action potential you have been observing is present 4 times per sweep and is accompanied by 1 other potential per sweep. The best explanation (gain 200 µV/div, 10 ms/div sweep speed, 10 divisions per screen) is that this represents:
a)
Normal recruitment and “psychogenic” weakness.
b)
Increased (early) recruitment as seen in a myopathy.
c)
Decreased (reduced) recruitment as seen in a neuropathy.
d)
Decreased (reduced) recruitment as seen in an upper motor neuron syndrome.
e)
Normal recruitment with poor effort.
13.
Which types of waveforms associated with hyperventilation may be seen by a needle electromyography examination?
a)
Doublets.
b)
Fibrillations.
c)
Complex repetitive discharges.
d)
Myokymic discharges.
e)
Positive sharp waves.
14.
An electrodiagnostic study may proceed without consent only when:
a)
The individual is incompetent to consent.
b)
Evaluating newborns for pathology.
c)
The patient is in a clinical emergency and is critically ill.
d)
The patient has no primary care physician.
e)
The patient is a minor with a legal guardian present.
15.
What effect would raising the low-frequency (high pass) filter up to 150 Hz with a constant high frequency filter cutoff have on nerve conduction studies with respect to duration and amplitude parameters of a compound muscle action potential?
a)
No change would occur.
b)
This would shorten the duration and lower the amplitude.
c)
This would lengthen the duration and lower the amplitude.
d)
This would shorten the duration and increase the amplitude.
e)
This would lengthen the duration and increase the amplitude.
16.
Which of the following findings would be most likely seen in a patient with active polymyositis?
a)
Long duration, large amplitude polyphasic motor units, predominantly in distally sampled muscles.
b)
Long duration, large amplitude polyphasic motor units, predominantly in proximally sampled muscles.
c)
Short duration, small amplitude polyphasic motor units, predominantly in distally sampled muscles.
d)
Short duration, small amplitude polyphasic motor units, predominantly in proximally sampled muscles.
e)
Normal motor units with reduced recruitment.
17.
Which of the following studies is most likely to be normal in an S1 radiculopathy?
a)
Sural sensory nerve action potential.
b)
Needle electromyography of the medial gastrocnemius muscle.
c)
Tibial-to-abductor hallucis (AH) compound muscle action potential (CMAP) amplitude.
d)
Tibial-to-AH F-wave latency.
e)
H-reflex.
18.
Which of the following is an example of a presynaptic neuromuscular junction disorder?
a)
Myasthenia gravis.
b)
Primary myopathy.
c)
Lambert-Eaton myasthenic syndrome.
d)
Anticholinesterase toxicity.
e)
Congenital myasthenic syndrome.
19.
A previously healthy 54-year-old male develops severe burning pain in his fingertips and numbness in his feet with profound fatigue and mild cardiomyopathy over the last 4 months. He has suffered with impotence for 1 year, and he now has recurrent diarrhea. There is no history of diabetes; he has a normal fasting glucose and no known toxic exposure. Nerve conduction testing shows absent sensory potentials in the lower extremities and severe bilateral carpal tunnel syndrome. Which of the following tests will be most likely abnormal and diagnostic?
a)
Serum levels of vitamin B12 and methylmalonic acid.
b)
Glucose tolerance test.
c)
Rectal biopsy.
d)
Abdomen and chest computed tomography scan.
e)
Heavy metal screen.
20.
Which study would be most helpful in differentiating a brachial plexus lesion from nerve root avulsion?
a)
H wave from the flexor carpi radialis.
b)
F-wave latency measurement.
c)
Sensory nerve action potential amplitude.
d)
Compound muscle action potential amplitude.
e)
Needle EMG of paraspinal muscles.
21.
Which neurotransmitter depolarizes the sweat glands?
a)
Epinephrine.
b)
Acetylcholine.
c)
Glycine.
d)
Glutamate.
e)
Norepinephrine.
22.
Decreasing the inter-electrode distance in a sensory nerve action potential recording will:
a)
Increase the amplitude.
b)
Decrease the amplitude.
c)
Increase the onset latency.
d)
Decrease the onset latency.
e)
Increase the duration.
23.
Complex repetitive discharges are characterized by which of the following?
a)
A gradual onset and slowing of the waveforms.
b)
Firing rates ranging from 1-5 Hz.
c)
Originating from ephaptic muscle fiber activation.
d)
An irregular firing rate of complex waveforms.
e)
Waxing and waning of amplitude.
24.
A 62-year-old man with diabetes complains of weakness, fatigue, and lightheadedness upon standing up. He also complains of “numbness” in his feet and a dry mouth. Which one of the following studies would be most helpful in establishing this patient’s diagnosis?
a)
Autonomic studies.
b)
Needle electromyography (EMG).
c)
Repetitive stimulation.
d)
Single-fiber EMG.
e)
Nerve biopsy.
25.
Myotonic discharges primarily in the paraspinal muscles would be most suggestive of:
a)
Myasthenia gravis.
b)
Myotubular myopathy.
c)
Botulinum intoxication.
d)
Acid maltase deficiency.
e)
Polymyositis.
26.
A 66-year-old male presents with bilateral hand weakness and difficulty swallowing. On examination he is noted to have significant finger flexor and mild hip flexor weakness. He has mild atrophy of his biceps, triceps, and intrinsic muscles. Muscle stretch reflexes are normal. No fasciculations are noted. Electrodiagnostic testing is most likely to reveal:
a)
Myotonic discharges.
b)
Conduction block.
c)
Fasciculations.
d)
Brief duration, low amplitude motor unit action potentials.
e)
Large amplitude, long duration motor unit action potentials.
27.
Which of the following is true regarding the neuromuscular junction?
a)
The postsynaptic membrane is 10 times longer than the presynaptic membrane.
b)
Miniature endplate potentials are responsible for muscle action potential.
c)
Synaptic transmission, like that of the nerve axon, is bidirectional.
d)
Synaptic vesicles contain acetylcholinesterase, an inactive form of acetylcholine (ACh).
e)
The synaptic cleft is 100 microns wide.
28.
Which of the following would be most appropriate in the recording of single-fiber potentials for jitter analysis?
a)
Positive to negative rise time of greater than 400 µs.
b)
Electrode uptake diameter of 1 mm.
c)
Electrode impedance greater than that of the amplifier.
d)
Peak-to-peak amplitude exceeding 200 µV.
e)
Filter settings of 10 Hz to 10 kHz.
29.
A 36-year-old woman experienced a mild upper respiratory tract infection 10 days ago from which she recovered without sequelae. Yesterday, she awoke with mild low aching back pain and tingling in her fingers and toes. This morning she awoke with more intense tingling in all extremities, and gait difficulty due to a combination of imbalance and mild weakness of her arms and legs. She presents to the emergency department where her examination is notable for mild diffuse weakness. An urgent electrodiagnostic study is requested. Which of the following findings is most likely to be discovered in this study?
a)
Prolongation of tibial H-wave latencies bilaterally.
b)
Prolonged motor distal latencies of tibial and fibular nerves.
c)
Reduced compound muscle action potential amplitudes of median and ulnar nerves.
d)
Increased sensory nerve action potential amplitudes of median and ulnar nerves
e)
Absent sural responses.
30.
Single-fiber electromyography is abnormal in which of the following conditions?
a)
Inclusion body myositis.
b)
Amyotrophic lateral sclerosis.
c)
Charcot–Marie–Tooth disease.
d)
All of the above.
e)
None of the above.
31.
Which of the following is a characteristic of both fibrillations and fasciculations?
a)
Regular firing rhythm.
b)
An initial negative deflection.
c)
Provocation by needle movement.
d)
Spontaneous occurrence.
e)
High frequency firing (over 50 Hz).
32.
An electrodiagnostic (EDX) medicine physician should stop an EDX evaluation if:
a)
The physician learns during the examination that the patient has hepatitis C.
b)
The patient initially agrees to testing, but later refuses to continue.
c)
The physician learns that the patient has no valid insurance.
d)
The patient notes that a recent international normalized ratio (INR) was 2.5.
e)
The patient exhibits minor discomfort during the needle exam.
33.
Which of the following conditions is most likely to clinically mimic lower moter neuron disease?
a)
Multifocal motor neuropathy.
b)
Lambert-Eaton myasthenic syndrome.
c)
Hereditary spastic paraplegia.
d)
Cervical myelopathy.
e)
Multiple sclerosis.
34.
In contrast to the F wave, the H wave:
a)
Utilizes a polysynaptic spinal cord reflex arc.
b)
Has a maximum amplitude with submaximal stimulation.
c)
Has a variable waveform at low rates of stimulation.
d)
Can be recorded from stimulation of any nerve/muscle.
e)
Is only found in the upper extremities.
35.
A patient had the suprascapular nerve completely severed 6 months ago in the course of a surgical procedure. While performing a needle electromyography for other reasons, you decide to examine the infraspinatus muscle. You find motor unit action potentials of normal configuration and recruitment pattern. What is the most likely explanation?
a)
The nerve has regenerated.
b)
The infraspinatus muscle has anomalous innervation.
c)
The needle is in the trapezius.
d)
The infraspinatus muscle is not normally innervated by the suprascapular nerve.
e)
The patient has a pre-fixed brachial plexus.
36.
Varying or unstable motor unit action potentials occur in which of the following?
a)
Acute, complete nerve transection.
b)
Lambert–Eaton myasthenic syndrome.
c)
Neurapraxia.
d)
Steroid myopathy.
e)
Normal aging.
37.
Which of the following disorders is most likely to be associated with normal needle electromyography findings when the study is performed at least 4 weeks after onset of symptoms?
a)
Inclusion body myositis.
b)
Botulinum toxin overdose.
c)
Nerve root avulsion.
d)
Steroid myopathy.
e)
Dermatomyositis.
38.
A 40-year-old woman presents with numbness and pain in the lateral and anterior thigh. A neuropathy of the right lateral cutaneous nerve of the thigh (meralgia paresthetica) is suspected. Which of the following answers best describes the lateral cutaneous nerve of the thigh?
a)
It is a pure sensory nerve that is derived from the L2-3 roots.
b)
It is a pure sensory nerve that is derived from the L4-5 roots.
c)
It is a pure sensory nerve that is derived from the L1-2 roots.
d)
It is a mixed sensory and motor nerve.
e)
It passes through the femoral canal.
39.
What is the advantage of a constant current stimulator versus a constant voltage stimulator when performing nerve conduction studies?
a)
Constant current stimulators deliver a consistent stimulus current that is impedance dependent.
b)
Constant voltage stimulators deliver a consistent current stimulation that is impedance independent.
c)
Constant current stimulators deliver a consistent current that is independent of impedance.
d)
Constant voltage stimulators deliver a varying current stimulus that is impedance dependent.
e)
Constant current stimulators are safer for patients with pacemakers.
40.
A 45-year-old man presents with right foot drop. On examination he has weakness of right foot dorsiflexion, inversion and eversion. Ankle plantar flexion, knee flexion, and extension strength are normal. Patellar and Achilles reflexes are normal. Which of the following, is the best diagnosis, reflecting an accurate localization of the lesion?
a)
Right fibular neuropathy at the knee.
b)
Right sciatic neuropathy.
c)
Right L5 radiculopathy.
d)
Right S1 radiculopathy.
e)
Right femoral neuropathy.
41.
The external anal sphincter can best be relaxed for needle electromyography examination by:
a)
Digital stretch with a finger placed in the anal canal.
b)
A long exhalation after a deep breath.
c)
Having the patient attempt to relax while lying on his or her side.
d)
Having the patient attempt to defecate.
e)
Applying a cold compress to the perianal area.
42.
Monopolar and concentric needle electrodes have the most similar characteristic in which of the following?
a)
Shape of the needle tip.
b)
Recorded firing rates.
c)
Recorded amplitudes.
d)
Recorded motor unit area.
e)
Electrical noise level.
43.
Axonotmesis is characterized by which of the following?
a)
Loss of axon but retained epineurium continuity.
b)
Loss of axon and loss of epineurium continuity.
c)
Persistent segmental conduction block.
d)
Axonal preservation but Schwann cell injury.
e)
Focal demyelination with preserved conduction.
44.
A 45-year-old man presents with weakness of his right hand. He denies sensory symptoms. Examination shows severe weakness in median-innervated distal hand intrinsic muscles with relative sparing of ulnar-innervated hand intrinsic muscles. Reflexes are reduced. Antiganglioside antibody titer is elevated. What is electrodiagnostic testing is most likely to reveal?
a)
Decreased activation.
b)
Early recruitment.
c)
Myotonic discharge.
d)
Conduction block.
e)
Fibrillation potentials in paraspinal muscles.
45.
Which of the following is true when performing nerve conduction studies in Lambert–Eaton myasthenic syndrome?
a)
Baseline compound muscle action potential (CMAP) is normal amplitude.
b)
Slow (2-3 Hz) repetitive nerve stimulation results in an incrementing response.
c)
Baseline CMAP is low amplitude.
d)
Endplate potential amplitude is normal at baseline.
e)
Fast stimulation results in a decrement.
46.
A patient with progressive sensorimotor neuropathy demonstrates severely and disproportionately prolonged distal motor latencies and diffusely absent sensory nerve action potentials. No site of focal motor conduction block is identified. Which antibodies are most likely to be present in this patient?
a)
Acetylcholine receptor antibodies.
b)
Myelin-associated glycoprotein antibodies.
c)
GM1 ganglioside antibodies.
d)
Voltage-gated potassium channel antibodies.
e)
Anti-MuSK antibodies.
47.
What effect would lowering the high-frequency (low pass) filter down to 500 Hz with a constant low-frequency cutoff on a compound muscle action potential with respect to the parameters of latency and amplitude?
a)
This would result in no change in either parameter.
b)
This would result in prolonged onset latencies and reduced amplitudes.
c)
This would result in shorter onset latencies and increased amplitudes.
d)
This would result in shorter onset latencies with no effect on amplitude.
e)
This would result in longer onset latencies and increased amplitudes.
48.
Which statement explains why the sensory nerve action potential is usually unaffected with a typical compressive radiculopathy?
a)
There is only a small segment of focal demyelination.
b)
There is no significant axonal degeneration.
c)
The lesion is usually proximal to the dorsal root ganglion.
d)
The lesion is usually distal to the dorsal root ganglion.
e)
The sensory fibers are more resistant to pressure than motor fibers.
49.
When interpreting repetitive nerve stimulation studies, which of the following is true?
a)
The majority of patients with presynaptic neuromuscular junction disorders have normal compound muscle action potentials at rest.
b)
At 2-3 Hz stimulation, Lambert–Eaton myasthenic syndrome (LEMS) demonstrates marked increment.
c)
Postactivation exhaustion is present in both LEMS and myasthenia gravis (MG).
d)
Abnormalities are demonstrated in asymptomatic muscles in MG.
e)
A 5% decrement is considered diagnostic for MG.
50.
If an initial positive deflection is seen in the morphology of the response when recording a compound muscle action potential, what would be the most likely cause?
a)
The active recording electrode is not placed exactly over the motor point.
b)
The stimulus is submaximal.
c)
The temperature is too low.
d)
The temperature is too high.
e)
The ground electrode is improperly placed.
51.
Hereditary neuropathy with liability to pressure palsy is characterized by which of the following?
a)
Autosomal recessive inheritance.
b)
X-linked inheritance.
c)
Painful neuropathy.
d)
Tomaculae on nerve biopsy.
e)
Hypertrophic 'onion bulb' formation.
52.
A 67-year-old with diabetes presents with 3 months of low back pain radiating into the right leg to the foot with paresthesias but no weakness. Her nerve conduction studies (NCSs) demonstrate normal fibular and tibial compound muscle action potentials and absent superficial fibular and sural sensory nerve action potentials on both legs. Needle electromyography demonstrates fibrillation potentials and long duration motor unit action potentials in the extensor digitorum brevis, tibialis posterior, and tibialis anterior muscles. Which of the following muscles, if abnormal, would be most supportive of an L5 radiculopathy?
a)
Adductor longus.
b)
Gluteus medius.
c)
Rectus femoris.
d)
Fibularis longus.
e)
Medial gastrocnemius.
53.
What are the effects of cool temperature on nerve conduction studies with respect to amplitude and nerve conduction velocity (NCV)?
a)
Increased amplitude and increased NCV.
b)
Increased amplitude and slowed NCV.
c)
Decreased amplitude and increased NCV.
d)
Increased amplitude and no change in NCV.
e)
Decreased amplitude and slowed NCV.
54.
Which of the following is true regarding the external anal sphincter?
a)
It receives innervation from the ilioinguinal nerve.
b)
It receives innervation via the dorsal rami of S2, S3, and S4.
c)
Its motor unit action potentials (MUAPs) are recordable at rest.
d)
Its MUAP discharge rate is greatest during sleep.
e)
It is composed entirely of smooth muscle.
55.
A 48-year-old railroad conductor has difficulty using his ticket puncher with his right hand. He has no sensory signs or symptoms. Examination demonstrates weakness of the adductor pollicis, first dorsal interosseous, but not abductor digiti quinti muscles. Other muscles examined in the right hand and arm are normal. What is the most likely diagnosis?
a)
Anterior interosseous nerve lesion.
b)
Posterior interosseous nerve lesion.
c)
Ulnar nerve lesion at the elbow.
d)
Ulnar nerve lesion at the wrist.
e)
Radial nerve lesion at the spiral groove.
56.
A fibrillation potential is a spontaneous depolarization of a:
a)
Sensory receptor.
b)
Muscle fiber.
c)
Nerve axon.
d)
Motor neuron.
e)
Neuromuscular junction.
57.
Motor unit action potential morphology is affected by which of the following parameters?
a)
Intrafusal fibers.
b)
Type 2 muscle fibers.
c)
Distance from the needle to the motor unit.
d)
Recruitment frequency.
e)
Skin impedance.
58.
Anti-GQ1b antibodies are frequently detected in which of the following conditions?
a)
Miller Fisher syndrome.
b)
Ocular myasthenia gravis.
c)
Chronic inflammatory demyelinating polyneuropathy.
d)
Lambert–Eaton myasthenic syndrome.
e)
Multifocal motor neuropathy.
59.
What are some methods to reduce electrode impedance mismatch and 60 Hz interference?
a)
Clean all dirt and oil from the skin using alcohol or acetone.
b)
Apply conducting electrode gel between the skin and electrodes.
c)
Place the ground between the stimulating and recording electrodes.
d)
All of the above.
e)
Increase the distance between active and reference electrodes.
60.
A mononeuropathy which produces lateral scapular winging that is at its most prominent during arm abduction would most likely exhibit weakness of which muscle?
a)
Serratus anterior.
b)
Subscapularis.
c)
Infraspinatus.
d)
Trapezius.
e)
Rhomboids.
61.
Which type of traumatic nerve injury is the most severe and carries a poor prognosis without surgical intervention?
a)
Neurotmesis.
b)
Neurapraxia.
c)
Conduction block.
d)
Axonotmesis.
e)
Segmental demyelination.
62.
During needle electromyography, conduction block would be recognized most easily by abnormalities in which of the following parameters?
a)
Activation.
b)
Insertional activity.
c)
Spontaneous activity.
d)
Recruitment.
e)
Duration.
63.
Which of the following is the most desirable technical condition for reliable repetitive nerve stimulation studies of the upper limb?
a)
Stimuli must be of long duration and submaximal.
b)
Skin temperature should be at least 33°C.
c)
The muscle should be allowed to move freely.
d)
Low frequency stimulation should be at 5 or 10 Hz.
e)
Fast stimulation should be at 50 Hz.
64.
In Bell's palsy, which of the following muscles will demonstrate abnormality with needle electromyography?
a)
Medial pterygoid.
b)
Lateral pterygoid.
c)
Masseter.
d)
Frontalis.
e)
Temporalis.
65.
Which is true regarding repetitive nerve stimulation in the evaluation of a suspected neuromuscular junction disorder?
a)
A normal compound muscle action potential excludes the diagnosis of Lambert–Eaton myasthenic syndrome.
b)
Immobilizing the area of study will degrade the waveform.
c)
Temperature must be maintained at 42°C.
d)
Patients with early stages of botulism may have normal tests.
e)
Repetitive stimulation is more sensitive than single-fiber EMG.
66.
Needle electromyography of which muscle is at highest risk of causing a pneumothorax?
a)
Infraspinatus.
b)
Posterior head of the deltoid.
c)
Supraspinatus.
d)
Latissimus dorsi.
e)
Serratus anterior.
67.
Why is neuromuscular transmission more likely to be impaired in proximal than distal muscles in myasthenia gravis?
a)
The motor units are larger in proximal muscles.
b)
Proximal muscles are warmer than distal muscles.
c)
More exposure to abnormal serum antibodies occurs in proximal muscles.
d)
Proximal muscles are stimulated more often than distal muscles.
e)
Distal muscles have fewer postjunctional folds.
68.
Sural nerve biopsy is most diagnostically informative in which condition?
a)
Idiopathic painful sensory neuropathy.
b)
Multifocal motor neuropathy.
c)
Mononeuritis multiplex.
d)
Alcoholic polyneuropathy.
e)
Vitamin B12 deficiency.
69.
Which 2 cervical roots are most commonly involved with burners or stingers?
a)
C3 and C4.
b)
C4 and C5.
c)
C5 and C6.
d)
C6 and C7.
e)
C7 and C8.
70.
Which of the following types of abnormal spontaneous activity is generated by a single muscle fiber?
a)
Fasciculation potential.
b)
Myokymic discharge.
c)
Neuromyotonic discharge.
d)
Myotonic discharge.
e)
Grouping discharge.
71.
The observation during peripheral nerve ultrasonography of ulnar nerve subluxation / dislocation during elbow flexion is most likely to be associated with which of the following findings on electrodiagnostic testing?
a)
Pseudo-conduction block of the ulnar nerve.
b)
The presence of a Martin–Gruber (median-to-ulnar) anastomosis.
c)
Myokymic discharges within the first dorsal interosseous.
d)
Erroneously normal ulnar nerve conduction velocity across the elbow.
e)
Low amplitude ulnar sensory response at the wrist.
72.
When compared to motor neurons that innervate type 2 muscle fibers, motor neurons that innervate type 1 muscle fibers have a:
a)
Faster conduction velocity.
b)
Lower threshold for recruitment.
c)
Higher firing frequency.
d)
Higher frequency of miniature endplate potentials.
e)
Larger soma size.
73.
A patient suffers from quadriceps weakness, and their ipsilateral femoral motor nerve conduction study (NCS) demonstrates diminished amplitude. The saphenous NCS is abnormal. The sartorius, iliopsoas, and vastus medialis muscles are abnormal and adductor longus and tibialis anterior are normal on needle electromyography. What is the most likely diagnosis?
a)
Lumbosacral plexopathy.
b)
L2-3 radiculopathy.
c)
Femoral neuropathy proximal to the inguinal ligament.
d)
Femoral neuropathy distal to the inguinal ligament.
e)
Obturator neuropathy.
74.
What is the optimal distance between the active and reference electrodes for recording a sensory nerve action potential?
a)
2.0-2.5 cm.
b)
2.5-3.0 cm.
c)
3.0-4.0 cm.
d)
4.0-5.0 cm.
e)
More than 6.0 cm.
75.
Which of the following ultrasonographic findings would be most consistent with the diagnosis of carpal tunnel syndrome?
a)
Increased nerve anisotropy.
b)
Increased nerve vascularity.
c)
Decreased thickness of the epineurium.
d)
Decreased bowing of the flexor retinaculum.
e)
Reduced cross-sectional area of the median nerve at the inlet.
76.
Acetylcholine is not the neurotransmitter used by:
a)
Sympathetic postganglionic fibers to the heart muscle.
b)
Sympathetic postganglionic fibers to the sweat glands.
c)
Parasympathetic preganglionic fibers.
d)
Sympathetic preganglionic fibers.
e)
Motor neurons at the neuromuscular junction.
77.
A 53-year-old man presents with right shoulder weakness. Needle electromyography shows denervation in the right deltoid, rhomboids, and biceps muscles. The right triceps and pronator teres are normal. Where is the lesion?
a)
Musculocutaneous nerve.
b)
C5 nerve root.
c)
C7 nerve root.
d)
Lateral cord brachial plexus.
e)
Upper trunk of the brachial plexus.
78.
Which of the findings listed is associated with poor outcome in Guillain–Barré syndrome?
a)
Fibrillation potentials observed in lumbar paraspinal muscles.
b)
Absent H wave.
c)
Absent fibular-to-extensor digitorum brevis F waves.
d)
Low amplitude tibial motor response.
e)
Normal cerebrospinal fluid protein level.
79.
A neuropraxic lesion of the fibular nerve at the fibular head would be associated with:
a)
Normal superficial fibular sensory nerve action potential amplitude.
b)
Normal fibular F waves stimulating at the knee and recording at the extensor digitorum brevis (EDB).
c)
Prolonged fibular motor distal latency to the EDB.
d)
Slowed sciatic nerve conduction velocity across the knee recording from the abductor digiti quinti (pedis).
e)
Reduced CMAP amplitude when stimulating at the ankle.
80.
In comparison to the compound muscle action potential (CMAP) amplitude, the amplitude of the F-wave response:
a)
Should be identical.
b)
Should be 1-10% of the amplitude of the preceding CMAP amplitude.
c)
Should be 2 times the amplitude of the preceding CMAP amplitude.
d)
Should be 25-50% of the amplitude of the preceding CMAP amplitude.
e)
Should be less than 0.1% of the CMAP amplitude.
81.
Short duration motor unit action potentials occur in which of the following scenarios?
a)
Chronic remote cervical radiculopathy.
b)
Postpolio syndrome.
c)
The low frequency filter is set at 500 Hz instead of 10 Hz.
d)
Trigeminal neuralgia.
e)
Late-stage reinnervation.
82.
A 35-year-old man presents with foot drop after prolonged crossing of his legs during an airline flight. You suspect a fibular neuropathy. What is the earliest point in time after onset of weakness can the motor nerve conduction studies of the fibular nerve provide definitive information regarding whether the foot drop is due to a severe axon loss or neurapraxia?
a)
Within 24 hours.
b)
1-3 days.
c)
4-7 days.
d)
10-14 days.
e)
21 days.
83.
In a lower trunk brachial plexus lesion, which of the following is most likely to be abnormal?
a)
Needle examination of the deltoid muscle.
b)
Needle examination of the extensor carpi radialis longus.
c)
Medial antebrachial cutaneous response, recording from the forearm.
d)
Lateral antebrachial cutaneous response, recording from the forearm.
e)
Median sensory response, recording from the thumb.
84.
Which of the following pathologic features are typically seen in acetylcholine receptor (AChR) antibody-positive myasthenia gravis?
a)
Increased postsynaptic area with more postjunctional folds and reduced synaptic space.
b)
Reduction of complement levels in the region of the postsynaptic membrane.
c)
Increased numbers of AChRs on the postsynaptic membrane.
d)
Crosslinking of AChR by antibodies, leading to reabsorption by the postsynaptic membrane.
e)
Reduction in presynaptic calcium channels.
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