PAM Electrotherapy Techniques 2 — Questions and Answers
Question 1: Which waveform characteristic describes the direction of current flow in alternating current (AC) used in electrotherapy?
- Current flows in one direction only
- Current reverses direction periodically (Correct answer)
- Current flows in pulses with no reversal
- Current maintains constant amplitude
Correct answer: Current reverses direction periodically
Alternating current (AC) reverses direction of flow periodically, distinguishing it from direct current.
Question 2: A clinician uses iontophoresis to deliver dexamethasone for inflammation. Which electrode polarity should be used for this negatively charged drug?
- Anode (positive)
- Cathode (negative) (Correct answer)
- Either polarity works equally
- Polarity does not affect drug delivery
Correct answer: Cathode (negative)
Negatively charged drugs are repelled from the cathode (negative electrode) and driven into tissue.
Question 3: What is the primary physiological effect of high-voltage pulsed current (HVPC) when used for wound healing?
- Increases local temperature to promote collagen synthesis
- Promotes galvanotaxis attracting fibroblasts and neutrophils (Correct answer)
- Reduces local blood flow to decrease edema
- Depolarizes sensory nerves to reduce pain
Correct answer: Promotes galvanotaxis attracting fibroblasts and neutrophils
HVPC promotes galvanotaxis, attracting immune cells and fibroblasts to the wound site to accelerate healing.
Question 4: Interferential current (IFC) uses two medium-frequency currents that intersect to produce a beat frequency. What range does this beat frequency typically fall within?
- 0–10 Hz
- 10–150 Hz (Correct answer)
- 500–1000 Hz
- 2000–4000 Hz
Correct answer: 10–150 Hz
The beat frequency of IFC typically ranges 10–150 Hz, which falls in the therapeutic low-frequency range for pain and muscle stimulation.
Question 5: During NMES application, a patient reports visible muscle fatigue after only 5 minutes. Which parameter adjustment would BEST reduce fatigue?
- Increase pulse duration
- Increase on:off duty cycle
- Decrease on:off duty cycle (Correct answer)
- Increase frequency to 100 Hz
Correct answer: Decrease on:off duty cycle
Decreasing the on:off duty cycle (e.g., 1:5) allows more muscle rest time between contractions, reducing fatigue.
Question 6: Which type of electrode placement for TENS produces the strongest analgesic effect via the gate control theory?
- Placing electrodes over the dorsal root ganglion
- Placing electrodes at acupuncture points distal to pain
- Placing electrodes directly over and surrounding the painful area (Correct answer)
- Placing electrodes proximal to the spinal cord level of pain
Correct answer: Placing electrodes directly over and surrounding the painful area
Conventional TENS placed directly over and around the painful area maximally activates large-diameter Aβ fibers to gate pain transmission.
Question 7: A patient has a cardiac pacemaker. Which electrotherapy modality is ABSOLUTELY contraindicated regardless of electrode placement?
- Low-frequency TENS below 10 Hz
- Neuromuscular electrical stimulation (NMES)
- Diathermy (shortwave or microwave) (Correct answer)
- High-volt pulsed current (HVPC)
Correct answer: Diathermy (shortwave or microwave)
Diathermy produces electromagnetic fields that can interfere with pacemaker function and is absolutely contraindicated.
PAM Electrotherapy Techniques 2
Which waveform characteristic describes the direction of current flow in alternating current (AC) used in electrotherapy?