Deck 9: Electromyography and Nerve Conduction Velocity Tests

Question 1

During insertion of the electromyography needle,the therapist notes an absence in insertional activity.What might this indicate?

A)Nothing,as there is no insertional activity in a normal muscle.
B)The membranes of the muscle are very unstable and excitable.
C)The muscle tissue is fibrotic,or the electrode is not in the muscle.
D)The muscle is acutely inflamed and sensitive.

Answer 1

C

Question 2

Nerve conduction velocity examination indicated an H-reflex latency of normal value for the S1 nerve roots.What does this tell the therapist?

A)A normal number of motor units were recruited during volitional contraction.
B)The sensory and motor pathways of the S1 nerve root are intact.
C)The sensory pathway of the S1 nerve root is intact,but the motor pathway is slow.
D)There are fewer motor unit action potentials than sensory action potentials produced.

Answer 2

B

Question 3

After cessation of insertional activity what would the therapist expect to see in a normal muscle?

A)Continued spikes in electrical activity
B)A slowing of electrical potentials
C)An absence of electrical potentials
D)Two to five electrical potentials

Answer 3

C

Question 4

When performing a nerve conduction velocity (NCV)test,the therapist notes a change in the temporal dispersion; specifically,the amplitude of the M wave is decreased.What might this indicate?

A)A very strong contraction of the muscle being tested.
B)Slow recruitment of the motor units being tested.
C)Decreased NCV of the nerve being tested
D)Partial denervation of the muscle being tested.

Question 5

What is the difference between testing sensory nerve conduction velocity using orthodromic conduction versus antidromic conduction?

A)Orthodromic conduction is more comfortable for the patient during stimulation.
B)Antidromic conduction examines the faster action potentials for sensation.
C)There is no difference other than the different types of electrodes used.
D)Orthodromic conduction examines velocity in the physiological direction.

Question 6

During an electromyography examination,what should the therapist expect to see as the patient increases the force of the muscle contraction?

A)An interference pattern as the potentials are summated
B)Increasing number of polyphasic action potentials
C)Decreasing numbers of motor unit action potentials
D)Lower amplitude of the potentials as they are summated

Question 7

What is telemetry?

A)Electrical activity that occurs from muscles other than the one being tested
B)Electrical activity recorded from a transmitter during movement
C)Unwanted electrical activity from tissues other than those being tested
D)The summation of electrical activity from a single motor unit being tested

Question 8

What is the best application of fine-wire electrodes?

A)They work best for electrical stimulation of muscles.
B)They work best for electromyography of large muscles.
C)They work best in patients with little body fat.
D)They work best in for electromyography of deep or narrow muscles.

Question 9

What is the frequency spectrum that should be used when using electromyography for kinesiological purposes with surface electrodes?

A)10 to 500 Hz
B)500 to 1000 Hz
C)75 to 150 Hz
D)10,000 to 100,000 Hz

Question 10

With a class 1 nerve injury (neurapraxia)what should a therapist expect to see from a nerve conduction velocity examination?

A)Increased latency above and below the point of nerve compression
B)Changes in patient tolerance to stimulation of the nerve
C)A normal response of the nerve fiber with stimulation
D)Increased latency of the nerve fiber over the point of compression

Question 11

What is cross-talk?

A)Electrical activity in muscles other than the one being tested
B)Electrical activity recorded from a transmitter during movement
C)Unwanted electrical activity from tissues other than those being tested
D)The summation of electrical activity from a single motor unit being tested

Question 12

During testing of quadriceps activity with the patient in a prone position,the therapist notes a low-frequency signal.What is the cause of this type of artifact?

A)Contraction of the hamstrings
B)Movement of the trunk
C)Signals from other muscles
D)Movement of the electrodes

Question 13

What are two variables that influence how much electrical activity is recorded by the electrodes during electromyography?

A)Type of electrode and percentage body fat of the patient
B)Muscle length and type of electrode used in the test
C)Size and number of muscle fibers and distance between fibers
D)Distance between muscle fibers and position of ground electrode

Question 14

What is the primary difference between electromyography (EMG)and nerve conduction velocity (NCV)examination?

A)With EMG testing the electrodes can be placed only in large muscles such as the quadriceps femoris.
B)With NCV testing the electrodes can be placed only in large muscles such as the quadriceps femoris.
C)With EMG testing measurements are taken from an evoked potential versus volitional potentials.
D)With NCV testing measurements are taken from an evoked potential versus volitional potentials.

Question 15

What factor can be expected to influence values of nerve conduction velocity?

A)Sex of the patient
B)Patient's chief complaint
C)Temperature of the limb
D)Choice of electrodes

Question 16

To determine nerve conduction velocity,what must the therapist do?

A)Perform a minimum of 10 repetitions of the stimulus at a distal point.
B)Determine the latency from a proximal and a distal point of stimulation.
C)Examine the strength of the motor response of the muscle tested.
D)Count how many action potentials occurred after stimulation of the nerve.

Question 17

During an electromyography exam the therapist observes fibrillation potentials.What might these indicate?

A)Lower motor neuron disorders such as peripheral nerve lesions
B)Primary muscle disease such as muscular dystrophy
C)Irritation of the anterior horn cell such as with nerve root compression
D)Upper motor neuron syndrome such as cerebral vascular accident

Question 18

Which response best characterizes the motor unit action potential found in a normal muscle?

A)Monophasic
B)Di- or triphasic
C)Polyphasic
D)Mono- or biphasic

Question 19

During an electromyography exam the therapist observes fasciculations.What might these indicate?

A)Lower motor neuron disorders such as peripheral nerve lesions
B)Primary muscle disease such as muscular dystrophy
C)Irritation of the anterior horn cell such as with nerve root compression
D)Upper motor neuron syndrome such as cerebral vascular accident

Question 20

Fibers of a motor unit contract almost synchronously with electrical potentials flowing through the surrounding tissues in an unpredictable pattern.Electrodes detect those signals reaching the electrode at essentially the same time.What is this concept?

A)Summation of response
B)Volume conduction
C)Motor unit volume
D)Fiber summation

Question 21

What is an indication for performing a kinesiologic electromyography examination?

A)To determine the nerve conduction speed of a moving muscle
B)To determine the irritability and inflammation of a nerve root
C)To determine when a patient needs surgical intervention
D)To determine patterns of muscular response and fatigue

Question 22

When performing a kinesiologic electromyography (EMG)examination on a patient,the examiner notes increase in EMG amplitude as the muscle begins to fatigue from multiple repetitions of the contraction.What can the therapist infer from this finding?

A)The muscle is functioning normally,as this is a typical finding.
B)The muscle is severely fatigued and will recover slowly.
C)The muscle has greater endurance than the therapist anticipated.
D)The muscle is hypertrophied and will recover quickly.

Question 23

What should the therapist look for on electromyography (EMG)that would indicate regeneration of a peripheral nerve?

A)Small polyphasic potentials observed with voluntary contraction
B)EMG changes that occur after changes are observed with manual muscle testing
C)An interference pattern that occurs very slowly during the test
D)Decreasing numbers of motor unit action potentials with contraction