Which of the following statements is TRUE regarding SNAP amplitudes?
are lower than normal with lesions of the ventral
horn
are lower than normal in a mixed (motor and sensory)
peripheral nerve if the myelin associated with all
of the axons is diseased
are normal in a mixed (motor and sensory) peripheral
nerve if all of the axons (versus myelin) are diseased
are normal in muscle disease
none of the statements are true
Weakness Practice question 2
Which of the following statements is TRUE regarding type grouping
and group atrophy?
occur during anterior horn disease
occur during NMJ disease
occur during muscle disease
commonly occur during myasthenia gravis
occur during myelin degeneration of a peripheral
nerve
Weakness Practice question 3
Which of the following statements is TRUE regarding a demyelinating
disease? (NO axis cylinder damage)
inflammation and an increase in blood CK
larger than normal MUPs
slower than normal conduction velocities
group atrophy
decrease in CMAP amplitude
Weakness Practice question 4
Which of the following statements is TRUE regarding a disease
of 75% of all axis cylinders (not myelin) in
a mixed (motor and sensory) peripheral nerve?
normal amplitude of SNAPs and CMAPs
normal conduction velocity
smaller than normal MUPs
decrement in CMAP response upon repetitive stimulation
absence of type grouping and group atrophy
Weakness Practice question 5
Which of the following statements is TRUE?
myasthenia gravis is an autoimmune disease
in which antibodies destroy norepinephrine receptors
in myasthenia gravis, there are smaller than
normal MUPs
in myasthenia gravis, there are lower than normal
CMAP and SNAP amplitudes
myasthenia gravis is caused by a defect of the neuromuscular
junction
in myasthenia gravis, there are large MUPs
Weakness Practice question 6
Which of the following statements is TRUE? (ALL parts
of the statement must be TRUE)
diseases of the neuromuscular junction never
result in abnormal fatigue on exercise
in Duchenne muscle dystrophy, the patient exhibits
large calves and distal muscle weakness
in primary muscle diseases, there are normal nerve
conduction velocities, normal SNAPs, and normal CMAPs
in primary muscle diseases, needle examination reveals
large MUPs
myotonia is sustained contraction
Weakness Practice question 7
Which of the following statements is TRUE?
blood CK is elevated in myasthenia gravis
an EMG that reveals decremental CMAP responses on
repeated nerve stimulation
indicates a disease of the muscle
type I muscle fibers are slow contracting
type grouping occurs in muscular dystrophy
inflammation is not indicative of myopathy
Weakness Practice question 8
Which of the following statements is TRUE regarding distal
polyneuropathies?
results in increased tendon reflexes
results in only motor deficits
sensory loss = glove and stocking distribution
effect is greater on proximal muscles than on distal
never seen in diabetes
Weakness Practice question 9
Which of the following statements is TRUE?
a SNAP represents the action potential of a
single axon
a CMAP represents the action potential of a
single muscle fiber
a motor unit is a single neuron in the ventral horn
and all of the muscle fibers that it innervates
a MUP represents the action potential of an entire
muscle
myasthenia gravis is a presynaptic defect
Weakness Practice question 10
Which of the following statements is TRUE regarding the result
of the lesion (shaded area) shown in the drawing below?
increase in amplitude of CMAPs upon stimulation
of innervating nerve
decrease in conduction velocity of innervating
nerve
decremental CMAP upon repetitive stimulation of innervating
nerve
increase in MUPs
increase in CK
Weakness Practice question 11
Which of the following statements is FALSE regarding the result
of the lesion (shaded area) shown in the
drawing below? Not all of the fibers are dead and both
the axis cylinder and myelin are affected.
type grouping
group atrophy
decrease in CMAP amplitude
decrease in MUPs
normal conduction velocities
Weakness Practice question 12
Which of the following statements is TRUE regarding the result
of the lesion shown in the drawing below?
ALL myelin is affected (gone) in the involved structures.
type grouping
group atrophy
decrease in CMAP amplitude
decrease in size of MUPs
decrease in conduction velocities
Weakness Practice question 13
Which of the following statements is FALSE regarding the result
of the lesion shown in the drawing below?
Only the axis cylinder (not the myelin) is affected in
the involved structures.
type grouping
group atrophy
decrease in conduction velocities
increase in size of MUPs
normal CK
Weakness Practice question 14
Which of the following statements is FALSE regarding the muscle
(and associated nerves) illustrated below?
decreased CMAP
group atrophy
decrease in conduction velocities
increase in size of MUPs
normal CK
Weakness Practice question 15
Which of the following statements is FALSE regarding the fiber
illustrated below?
is a hypomyelinated fiber
fiber conducts more slowly than normal
fiber can convey an action potential
the axon will sprout in the associated muscle
the MUP associated with this fiber is normal
Weakness Practice question 16
Which of the following statements is TRUE regarding the information
shown in the drawing below?
would result from a lesion in the ventral horn
would result from a demyelinating disease
could be caused by antibodies to acetylcholine receptors
could result from a lesion of the lateral corticospinal
tract (LCST)
