Modalities - Electrical Currents

The pulse duration includes all of the following EXCEPT:

a. Interpulse interval
b. All phases of a pulse
c. Interphase interval
d. Rise time

a. Interpulse interval

All of the following are synonymous pairs EXCEPT:
a. Frequency, rate
b. Amplitude, intensity
c. Current, voltage
d. Bidirectional, biphasic

c. Current, voltage

Which of the following statements is true?
a. It is possible to stimulate sensory, motor, and pain fibers simultaneously
b. Placing an electrode near or over a motor point will be more painful than if the electrode is placed away from a motor point
c. When using electrodes of different sizes in a single circuit, the current density will be greater at the larger electrode
d. Monophasic current is generally more comfortable than biphasic current

a. It is possible to stimulate sensory, motor, and pain fibers simultaneously

All of the following cause high impedance to current flow EXCEPT:
a. bone
b. fat
c. water
d. hair

c. water

Changing the ramp-up time will:
a. Change the frequency
b. Affect whether or not accommodation occurs
c. Affect when the series of pulses reaches peak amplitude
d. Affect what type of nerve fiber will be stimulated

c. Affect when the series of pulses reaches peak amplitude

Is it possible to stimulate only sensory fibers with a device that has a fixed pulse duration of 200 microseconds?
a. No
b. Yes, by using a lower frequency (e.g., <30 pulses per second [pps])
c. Yes, by using a higher frequency (e.g., >30 pps)
d. Yes, by using a low amplitude

d. Yes, by using a low amplitude

How could the pulse duration of a current be decreased without changing the frequency?
a. This is not possible with any type of current
b. The rise time must increase
c. This is only possible for a monophasic current
d. The interpulse interval must increase

d. The interpulse interval must increase

Which of the following pulse durations would be the best choice for producing a muscle contraction?
a. 2 microseconds
b. 20 microseconds
c. 200 microseconds
d. 2 milliseconds

c. 200 microseconds

For an interferential current, what happens to the beat frequency when the frequency of one of the circuits is decreased from 4100 Hz to 4050 Hz and the frequency of the other circuit stays fixed at 4000 Hz?
a. Increases
b. Decreases
c. Remains the same
d. None of the above

b. Decreases

When two alternating currents cross paths and the peak of one current intersects with the trough of the other current, what is the result?
a. The currents will summate to produce a high positive amplitude at the area of interference
b. The currents will summate to produce a high negative amplitude at the area of interference
c. The currents will summate to produce zero current amplitude at the area of interference
d. The currents will be repelled from each other

c. The currents will summate to produce zero current amplitude at the area of interference

All of the following are proposed advantages of using interferential current EXCEPT:
a. Increased comfort
b. Larger treatment area
c. Ability to produce muscle contractions
d. Can target an area between the electrodes

c. Ability to produce muscle contractions

Regarding action potentials (AP), which one of the following statements is true?
a. Increasing intensity to suprathreshold levels will increase the magnitude of an AP
b. A longer rise time will decrease threshold potential, thus improving generation of an APs
c. Increasing current amplitude will increase the number of nerve fibers stimulated
d. The speed of propagation of an AP depends on the current amplitude

c. Increasing current amplitude will increase the number of nerve fibers stimulated

Which of the following changes to an electrical stimulation current will most effectively increase the number of APs generated?
a. Increasing the rise time
b. Increasing the ramp-up time
c. Decreasing the ramp-up time
d. Increasing the frequency

d. Increasing the frequency

To reduce the likelihood of adaptation, devices have been engineered to modulate (i.e., automatically vary during a treatment) all of the following characteristics EXCEPT:
a. Amplitude
b. Type of waveform
c. Frequency
d. Pulse duration

b. Type of waveform

It would be LEAST appropriate to use a current that had an on:off time for…
a. Pain control with “conventional TENS”
b. Edema reduction by muscle pumping
c. Muscle strengthening
d. Increasing muscle endurance

a. Pain control with “conventional TENS”

Which type of current is used for iontophoresis?
a. DC (Direct Current)
b. AC (Alternating Current)
c. PC (Pulsed Current)
d. All of the above can be used

a. DC (Direct Current)

Which one of the following statements regarding iontophoresis is true?
a. The administration of medication via iontophoresis does not require a physician prescription
b. The polarity of the delivery electrode should be opposite to the active ion in the medication
c. Drugs used for iontophoresis must be water-soluble
d. Use of superficial heat before iontophoresis is recommended to improve delivery of medication

c. Drugs used for iontophoresis must be water-soluble

Your patient complains of pain and has swelling at the right lateral ankle after an inversion sprain yesterday. You have chosen the following electrical stimulation parameters for treatment: monophasic PC with a fixed pulse duration of 40 microseconds, frequency of 120 pps, amplitude at 90% of motor threshold, electrode of negative polarity at the lateral ankle. The best rationale for this treatment is:
a. Remove edema that is already present
b. Decrease pain and retard edema formation
c. Improve venous return
d. Decrease pain and strengthen the surrounding muscles

b. Decrease pain and retard edema formation

If a patient reported being unable to feel a current with 100 pps frequency during a TENS treatment, which of the following changes is most likely to produce a sensation?
a. Increasing the current amplitude
b. Increasing the frequency to 150 pps
c. Decreasing the frequency to 80 pps
d. Decreasing the pulse duration

a. Increasing the current amplitude

A beat is produced by interference of which of the following types of current?
a. Direct current
b. Biphasic symmetrical pulsed
c. Alternating
d. Biphasic asymmetrical pulsed

c. Alternating

After having stimulated a muscle contraction with a 35 pps frequency current, which of the following pulse frequencies is most likely to increase the force of a second contraction?
a. 8 pps
b. 80 pps
c. 800 pps
d. 8000 pps

b. 80 pps

One can increase the depth to which a current penetrates by:
a. Decreasing the current amplitude
b. Increasing the pulse frequency
c. Increasing the distance between electrodes
d. Increasing the ramp-up time

c. Increasing the distance between electrodes

Biphasic PC may be effective for all of the following EXCEPT:
a. To control pain
b. To strengthen innervated muscles
c. To prevent muscle atrophy in denervated muscles
d. To decrease spasticity by stimulating either spastic muscles or their antagonists

c. To prevent muscle atrophy in denervated muscles

All of the following are examples of using functional electrical
stimulation (FES) in treatment EXCEPT:
a. To stimulate ankle dorsiflexors during gait
b. To stimulate wrist extensors for a tenodesis grasp in a patient with a spinal cord injury
c. To substitute for an orthotic
d. To control pain in the hemiplegic shoulder

d. To control pain in the hemiplegic shoulder

Theoretical rationale(s) for using neuromuscular electrical stimulation (NMES) for muscle strengthening include:
a. Greater strength gains will occur when training with higher force muscle contractions
b. Electrical stimulation recruits more large motor neurons and thus more type II muscle fibers
c. Electrical stimulation recruits more small motor neurons and thus more type I muscle fibers.
d. Both a and b
e. Both a and c

d. Both a and b

For a patient receiving neuromuscular stimulation (NMES) to
increase biceps and brachialis strength, which of the following electrode configurations is most likely to maximize elbow flexion force using 2-inch electrodes?
a. Two electrodes placed perpendicular to the muscle fibers, 1 inch apart
b. Two electrodes placed perpendicular to the muscle fibers, 2½ inches apart
c. Two electrodes placed parallel to the muscle fibers, 1 inch apart
d. Two electrodes placed parallel to the muscle fibers, 2½ inches apart

d. Two electrodes placed parallel to the muscle fibers, 2½ inches apart

Which of the following parameter(s) is/are different for conventional TENS and acupuncture-like TENS?
a. Frequency
b. Pulse duration
c. Amplitude
d. All of the above

d. All of the above

All of the following are contraindications for the use of electrical stimulation (ES) EXCEPT:
a. For patients with a demand cardiac pacemaker
b. ES near an open wound
c. ES over a carotid sinus
d. ES in a patient who is pregnant

b. ES near an open wound

Which scenario is LEAST likely to cause burns?
a. Electrical stimulation over insensate skin
b. One electrode falls off
c. Electrodes placed over bony prominences
d. Electrodes that are still in contact with skin but the edges are peeling off

b. One electrode falls off