Deck 11: Foundations for Electrical Stimulation

Question 1

What chemical reaction takes place at the interface between the positive electrode and underlying tissue?

A)The formation of hydrochloric acid, which softens tissues
B)The formation of sodium hydroxide, which softens tissues
C)The formation of hydrochloric acid, which hardens tissues
D)The formation of sodium hydroxide, which hardens tissues

Answer 1

C

Question 2

Which statement is most accurate regarding a constant current stimulator?

A)There is no such device as a constant current stimulator.
B)Constant current stimulators produce harmful levels of current when the resistance of the electrode has decreased.
C)The voltage increases to maintain the same level of current when the resistance increases.
D)Constant current stimulators produce current that does not vary, regardless of resistance.

Answer 2

D

Question 3

What is the potential clinical significance for an on ramp on a biphasic stimulator?

A)If a muscle contraction is elicited, the on ramp provides the patient with a warning that the stimulus will be getting stronger.
B)If a muscle contraction is elicited, the on ramp provides the patient with the opportunity to hold the contraction after the stimulus has ended.
C)The on ramp prevents the clinician from turning the stimulus up too quickly.
D)The on ramp prevents the clinician from turning the stimulus off too quickly.

Answer 3

A

Question 4

Which of the following definitions best describes pulsed current?

A)The unidirectional uninterrupted flow of charged particles with a duration of at least one second
B)The bidirectional uninterrupted flow of charged particles changing direction at least once per second
C)The unidirectional or bidirectional flow of charged particles periodically ceasing for less than one second before the next electrical event
D)A monophasic waveform that remains constantly above or below isoelectric zero for more than one second

Question 5

Which type of waveform is most likely to produce a net charge in the underlying tissue?

A)An unbalanced waveform
B)A balanced waveform
C)A symmetrical waveform
D)An asymmetrical waveform

Question 6

Why does the diagram of the waveform rarely reflect what the patient is actually receiving?

A)It is affected by the intensity of the stimulation.
B)It is affected by the capacitance and reactance of the tissue.
C)It is affected by the capacitance and intensity of the stimulation.
D)It is not affected; it will be the same.

Question 7

Which of the following potential changes is more likely to occur with an asymmetrical waveform than with a symmetrical waveform?

A)An electrical burn
B)A polar change in the underlying tissues
C)A pinching sensation
D)All of the above

Question 8

Which of the following statements most accurately describes the characteristics of biphasic waveforms?

A)Biphasic waveforms have a negative phase that is symmetrical with the positive phase.
B)Biphasic waveforms have a positive phase that is asymmetrical with the negative phase.
C)Biphasic waveforms have two phases.
D)Biphasic waveforms have a result of no net charge.

Question 9

What effect does the amount of adipose tissue have on the impedance of the underlying tissues?

A)Adipose tissue has no effect on impedance.
B)The larger the amount of adipose tissue, the lower the impedance of the tissue.
C)The smaller the amount of adipose tissue, the higher the impedance of the tissue.
D)The smaller the amount of adipose tissue, the lower the impedance of the tissue.

Question 10

What is the potential clinical significance for an off ramp on a biphasic stimulator?

A)If a muscle contraction is elicited, the off ramp provides the patient with a warning that the stimulus will be getting stronger.
B)If a muscle contraction is elicited, the off ramp provides the patient with the opportunity to hold the contraction after the stimulus has ended.
C)The off ramp prevents the clinician from turning the stimulus up too quickly.
D)The off ramp prevents the clinician from turning the stimulus off too quickly.

Question 11

Which waveform has the ability to activate peripheral nerves with minimal electrical charge and has minimal potential for skin reactions?

A)Monophasic
B)Symmetrical biphasic
C)Asymmetrical monophasic
D)Asymmetrical biphasic

Question 12

Which of the following statements is most accurate regarding the stimulation of nerve fiber?

A)Nerve fiber stimulation with electrical stimulation is uncomfortable.
B)Smaller diameter fibers require lower levels of stimulation to elicit a response.
C)Larger diameter fibers require higher levers of stimulation to elicit a response.
D)Larger diameter fibers require lower levels of stimulation to elicit a response.

Question 13

What two conditions are necessary for current to flow?

A)An energy source that creates a difference in electrical potential and a conductor
B)Current and ions
C)Current and a conductor
D)An energy source that creates a difference in electrical potential and a capacitor

Question 14

What chemical reaction takes place at the interface between the negative electrode and underlying tissue?

A)The formation of hydrochloric acid, which softens tissues
B)The formation of sodium hydroxide, which softens tissues
C)The formation of hydrochloric acid, which hardens tissues
D)The formation of sodium hydroxide, which hardens tissues

Question 15

What is the difference between a monophasic pulsed waveform and direct current?

A)A monophasic pulsed waveform is either positive or negative and is the same as direct current.
B)A monophasic pulsed waveform is unidirectional, but it flows for a longer period of time than direct current.
C)A monophasic pulsed waveform is pulsed current, and direct current is uninterrupted.
D)There is no difference between a monophasic pulsed waveform and direct current.

Question 16

Which of the following definitions best describes alternating current?

A)The unidirectional uninterrupted flow of charged particles with a duration of at least one second
B)The bidirectional uninterrupted flow of charged particles changing direction at least once per second
C)The unidirectional or bidirectional flow of charged particles periodically ceasing for less than one second before the next electrical event
D)A monophasic pulse that randomly changes phase at least twice within one minute

Question 17

Which of the following definitions best describes direct current?

A)The unidirectional uninterrupted flow of charged particles with a duration of at least one second
B)The bidirectional uninterrupted flow of charged particles changing direction at least once per second
C)The unidirectional or bidirectional flow of charged particles periodically ceasing for less than one second before the next electrical event
D)A monophasic pulse that changes phase at least twice within one second

Question 18

What is meant by the term "capacitance," and what biologic tissue has this quality?

A)The ability to conduct charge in an electric field; nerve
B)The ability to store charge in an electric field and oppose change in current flow; muscle membranes
C)The ability to resist the flow of current in an electric field; adipose tissue
D)None of the above

Question 19

Impedance changes in the presence of injury and disease and will increase with which of the following?

A)Edema, ischemia, atherosclerosis, scarring, and denervation
B)Open wounds
C)Abrasions
D)All of the above

Question 20

According to Ohm's law, which of the following statements is most accurate?

A)Current flow is indirectly proportional to voltage.
B)Current flow is directly proportional to voltage.
C)Current flow is not related to voltage; it is related to resistance.
D)Current flow will decrease when voltage decreases regardless of resistance.

Question 21

What are the indications for clinical electrical stimulation?

A)Pain management
B)Muscle strengthening
C)Stimulation of denervated muscle
D)All of the above

Question 22

What is the advantage of a carrier frequency?

A)It is more comfortable for patients and overcomes skin resistance easily.
B)It is more readily available than not having a carrier frequency.
C)It is delivered to the patient in a low frequency current.
D)There is no advantage.

Question 23

What happens to the impedance of human skin as a result of the addition of electrical stimulation?

A)It increases.
B)It decreases.
C)It remains unchanged.
D)It can burn.

Question 24

What type of current output is necessary for iontophoretic devices to be able to accomplish the delivery of a medication to a patient?

A)Alternating current
B)Direct current
C)Pulsed current
D)Either alternating or direct current, depending upon the manufacturer

Question 25

What is the normal pH of the skin?

A)1 to 2
B)3 to 4
C)5 to 6
D)7 to 8

Question 26

When using iontophoresis to enhance the transcutaneous permeation of ionic drugs into the skin, what polarity must the electrode be in relationship to the medication?

A)There is no relationship between the polarity of the medication and the electrode.
B)The polarity of the medication and the electrode should be the same.
C)The polarity of the medication and the electrode should be the opposite of each other.
D)As long as the electrode with the medication is hydrated, the polarity of the electrode makes no difference.

Question 27

What is the main reason that polarity effects are less with pulsed current than with DC?

A)There are intrapulse intervals, which allow the tissue to adapt to the current and neutralize the chemical effects between pulses.
B)There are no intrapulse intervals, which allow the tissue to adapt to the current and neutralize the chemical effects between pulses.
C)There are more polarity effects with pulsed current than with DC.
D)The effects of polarity are not any different, whether pulsed or not.

Question 28

Which of the following is the most important consideration and is also a contraindication to iontophoresis that must be considered by everyone involved in the administration of the treatment prior to the application of iontophoresis?

A)Whether or not the patient has insurance coverage for treatment
B)Whether or not the patient has a signed consent for treatment
C)Whether or not the patient has an allergy to the medication to be administered
D)Whether the time the patient has allotted for treatment is long enough to accomplish the treatment goals

Question 29

Iontophoretic delivery of medications is preferable for drugs that have all of the following characteristics except which?

A)The ability to be utilized for topical effects
B)Require constant plasma levels
C)Demonstrate significant liver metabolism
D)The ability to be delivered in a non-ionized form

Question 30

Time enhances passive drug delivery. All of the following statements are true except which one?

A)Augmented passive drug delivery continues following termination of the applied current.
B)Iontophoretic applicators should remain in place to maximize the amount of drug delivered transcutaneously.
C)Longer treatment times will afford potentially greater drug delivery.
D)Higher intensities during the treatment time with iontophoresis will negate the need for passive drug delivery.

Question 31

What parameters are adjusted to determine the dosage for iontophoresis to accomplish therapeutic treatment goals?

A)Strength of medication and pulse duration
B)Intensity and pulse duration
C)Treatment time and strength of medication
D)Treatment time and intensity

Question 32

What effect does tissue hydration have on the impedance value of the skin?

A)Lower hydration results in no change in impedance.
B)Higher hydration results in higher impedance.
C)Higher hydration results in reduced impedance.
D)Lower hydration results in reduced impedance.

Question 33

The term "iontophoresis" implies which of the following?

A)The use of electrical stimulation to deliver medication into the body
B)The use of large amounts of physiologically acceptable electric current to deliver drugs into the body
C)The use of small amounts of physiologically acceptable electric current to deliver drugs into the body
D)The use of ultrasound to deliver medication into the body

Question 34

Which of the following terms is not a synonym for frequency?

A)Rate
B)Hertz
C)Cycles per second
D)Duty factor

Question 35

What does the term "modulation" refer to on an electrical stimulator, and why might you select it for a patient?

A)It refers to the ability to modify intensity, and it is used to adjust the strength of the stimulus.
B)It refers to the ability to vary whether or not both channels are operating at the same time or not, and it is useful when agonist/antagonist protocols are part of the treatment intervention.
C)It refers to the ability to vary one or more of the parameters over time, and it may help to decrease adaptation to the current.
D)Modulation is an undesirable effect due to line leakage and should be avoided.