OTD 433 CERTIFICATION REVIEW 2026
QUESTIONS WITH ANSWERS GRADED A+
>> The movement of free electrons from one atom to another is called
Answer: electric current
>> Electric current prefers the path of ________ resistance
Answer: least
>> This therapeutic current moves in one direction, is monophasic and is
delivered continuously until the current is turned off
Answer: direct current (galvanic)
>> Iontophoresis, EMS, and ESTR are all examples of which therapeutic
current?
Answer: direct current
>> Acidic reactions occur at the ________ and alkaline reactions occur at
______
Answer: anode, cathode
>> This therapeutic current is bidirectional, biphasic and the electrons shuffle
back between 2 electrodes, alternating between (+) and (-). The current has no
true positive or negative charge.
Answer: alternating current (AC)
>> TENS, FES, and NMES are all examples of which kind of therapeutic
current?
Answer: Alternating current
,>> This therapeutic current is periodically interrupted flow of charged particles
and can be monophasic or biphasic.
Answer: Pulsatile current
>> A picture of an electrical current is called a
Answer: waveform
>> An area within the waveform that represents total current is called
Answer: pulse
>> What are the 3 pulsatile waveforms?
Answer: monophasic, biphasic, and polyphasic
>> The strength of current, associated with force of contraction
Answer: amplitude/intensity
>> The length of time that the electrical flow is "on"
Answer: pulse duration/pulse width
>> If you wanted to penetrate deep structures, would you want a long pulse
duration or a short pulse duration?
Answer: long
>> What happens if the pulse duration is too short?
Answer: there is no action potential
>> What is the measurement of pulse duration?
Answer: microseconds (µS)
>> At a pulse duration of 20 - 100 µs, what structures are being stimulated?
,Answer: sensory nerves - Large diameter A-beta nerve fibers that are
hyperstimulated to over-ride pain
>> At a pulse duration of 200 - 400 µs, what structures are being stimulated?
Answer: motor nerves - Recruits large diameter A-alpha motor
nervesnecessary for muscle contraction
>> At a pulse duration of 400 - 1000 µs, what structures are being stimulated?
Answer: Pain carrying nerve fibers - Used in noxious electrotherapy
protocolsConcept of "pain relieving pain"
>> The number of events per second is called
Answer: pulse frequency
>> Pulse frequency is measured in ___ or ___
Answer: pps, Hz
>> Which is more comfortable for the client, a slow pulse frequency or fast pulse
frequency?
Answer: fast
>> In NMES, 15-25Hz pulse frequency is suitable for what kinds of clients?
Answer: weak patients (stroke, TBI, debilitated)
>> In NMES, 35-45 Hz pulse frequency is suitable for what kinds of clients?
Answer: otherwise healthy patients such as ortho
>> In NMES, what is 50-60 Hz pulse frequency used for?
Answer: to fatigue spastic muscles
>> In TENS, 60+ Hz pulse frequency is for
, Answer: pain relief
>> The time needed for the pulse to reach its peak value is called
Answer: pulse rise time
>> The time needed for the pulse to go from peak to zero is called
Answer: pulse decay time
>> Individual patterns of waveforms, durations and/or frequencies that are linked
together (repeated at regular intervals)
Answer: pulse train
>> The gradual rise or fall in amplitude of a pulse train (cause a gradual change
in the force of muscle contractions by progressive motor unit recruitment)
Answer: amplitude ramp
>> What effects does NMES produce at the cellular level?
Answer: modifies fibroblastic and osteoblast activity, facilitates
microcirculation, increases metabolic rate
>> How does NMES facilitate endogenous opiates for pain relief?
Answer: fatigues muscles which increases the release of opiates
>> What kinds of tissues have high resistance?
Answer: fat, dry skin
>> What kinds of tissues have low resistance?
Answer: muscle, clean, healthy skin
>> What is impedance?
QUESTIONS WITH ANSWERS GRADED A+
>> The movement of free electrons from one atom to another is called
Answer: electric current
>> Electric current prefers the path of ________ resistance
Answer: least
>> This therapeutic current moves in one direction, is monophasic and is
delivered continuously until the current is turned off
Answer: direct current (galvanic)
>> Iontophoresis, EMS, and ESTR are all examples of which therapeutic
current?
Answer: direct current
>> Acidic reactions occur at the ________ and alkaline reactions occur at
______
Answer: anode, cathode
>> This therapeutic current is bidirectional, biphasic and the electrons shuffle
back between 2 electrodes, alternating between (+) and (-). The current has no
true positive or negative charge.
Answer: alternating current (AC)
>> TENS, FES, and NMES are all examples of which kind of therapeutic
current?
Answer: Alternating current
,>> This therapeutic current is periodically interrupted flow of charged particles
and can be monophasic or biphasic.
Answer: Pulsatile current
>> A picture of an electrical current is called a
Answer: waveform
>> An area within the waveform that represents total current is called
Answer: pulse
>> What are the 3 pulsatile waveforms?
Answer: monophasic, biphasic, and polyphasic
>> The strength of current, associated with force of contraction
Answer: amplitude/intensity
>> The length of time that the electrical flow is "on"
Answer: pulse duration/pulse width
>> If you wanted to penetrate deep structures, would you want a long pulse
duration or a short pulse duration?
Answer: long
>> What happens if the pulse duration is too short?
Answer: there is no action potential
>> What is the measurement of pulse duration?
Answer: microseconds (µS)
>> At a pulse duration of 20 - 100 µs, what structures are being stimulated?
,Answer: sensory nerves - Large diameter A-beta nerve fibers that are
hyperstimulated to over-ride pain
>> At a pulse duration of 200 - 400 µs, what structures are being stimulated?
Answer: motor nerves - Recruits large diameter A-alpha motor
nervesnecessary for muscle contraction
>> At a pulse duration of 400 - 1000 µs, what structures are being stimulated?
Answer: Pain carrying nerve fibers - Used in noxious electrotherapy
protocolsConcept of "pain relieving pain"
>> The number of events per second is called
Answer: pulse frequency
>> Pulse frequency is measured in ___ or ___
Answer: pps, Hz
>> Which is more comfortable for the client, a slow pulse frequency or fast pulse
frequency?
Answer: fast
>> In NMES, 15-25Hz pulse frequency is suitable for what kinds of clients?
Answer: weak patients (stroke, TBI, debilitated)
>> In NMES, 35-45 Hz pulse frequency is suitable for what kinds of clients?
Answer: otherwise healthy patients such as ortho
>> In NMES, what is 50-60 Hz pulse frequency used for?
Answer: to fatigue spastic muscles
>> In TENS, 60+ Hz pulse frequency is for
, Answer: pain relief
>> The time needed for the pulse to reach its peak value is called
Answer: pulse rise time
>> The time needed for the pulse to go from peak to zero is called
Answer: pulse decay time
>> Individual patterns of waveforms, durations and/or frequencies that are linked
together (repeated at regular intervals)
Answer: pulse train
>> The gradual rise or fall in amplitude of a pulse train (cause a gradual change
in the force of muscle contractions by progressive motor unit recruitment)
Answer: amplitude ramp
>> What effects does NMES produce at the cellular level?
Answer: modifies fibroblastic and osteoblast activity, facilitates
microcirculation, increases metabolic rate
>> How does NMES facilitate endogenous opiates for pain relief?
Answer: fatigues muscles which increases the release of opiates
>> What kinds of tissues have high resistance?
Answer: fat, dry skin
>> What kinds of tissues have low resistance?
Answer: muscle, clean, healthy skin
>> What is impedance?
