NPTE-PTA Therapeutic Modalities and Electrotherapy 2 — Questions and Answers
Question 1: TENS (Transcutaneous Electrical Nerve Stimulation) in conventional mode works primarily through which pain mechanism?
- Endorphin release
- Gate control theory (Correct answer)
- Tissue heating
- Alpha motor neuron inhibition
Correct answer: Gate control theory
Conventional TENS uses high-frequency, low-intensity current to activate large-diameter A-beta sensory fibers, which inhibit pain signal transmission via the gate control mechanism.
Question 2: Which ultrasound application technique is required when treating bony or irregular surface areas?
- Stationary technique
- Moving transducer technique
- Water immersion technique (Correct answer)
- Air-coupling technique
Correct answer: Water immersion technique
Water immersion ultrasound is used for irregular surfaces (hands, feet, ankles) because water provides a coupling medium and allows the transducer to maintain contact without direct pressure on bony prominences.
Question 3: A patient is receiving NMES (Neuromuscular Electrical Stimulation) for quadriceps re-education post-ACL repair. The on:off ratio should be set to:
- 1:1 for maximum endurance training
- 1:5 to allow adequate muscle recovery between contractions (Correct answer)
- 3:1 for rapid fatigue training
- 2:2 for equal work-rest balance
Correct answer: 1:5 to allow adequate muscle recovery between contractions
An on:off ratio of 1:5 (e.g., 10 seconds on, 50 seconds off) allows sufficient recovery time to minimize muscle fatigue during NMES strengthening sessions.
Question 4: Which laser safety classification is typically used in therapeutic photobiomodulation (low-level laser therapy)?
- Class 1 (exempt)
- Class 2 (low power visible)
- Class 3B (medium power) (Correct answer)
- Class 4 (high power)
Correct answer: Class 3B (medium power)
Therapeutic low-level laser therapy typically uses Class 3B lasers (5–500 mW), which require safety eyewear to prevent eye damage but are non-thermal for tissue.
Question 5: What is the therapeutic depth of penetration for a hot pack (hydrocollator)?
- 0–0.5 cm (superficial skin only)
- 1–2 cm (superficial tissues) (Correct answer)
- 3–5 cm (deep muscle)
- 5–7 cm (joint capsule)
Correct answer: 1–2 cm (superficial tissues)
Hot packs heat superficial tissues to a depth of approximately 1–2 cm; deeper muscles are not significantly heated by this modality.
Question 6: Which of the following is a contraindication for the use of electrical stimulation?
- Chronic muscle atrophy
- Active malignancy in the treatment area (Correct answer)
- Delayed-onset muscle soreness
- Mild peripheral edema
Correct answer: Active malignancy in the treatment area
Electrical stimulation is contraindicated over areas of active malignancy because it may stimulate tumor cell proliferation or spread through increased blood flow.
NPTE-PTA Therapeutic Modalities and Electrotherapy 2
TENS (Transcutaneous Electrical Nerve Stimulation) in conventional mode works primarily through which pain mechanism?