NPTE-PT Test Test Therapeutic Modalities Application 1 — Questions and Answers
Question 1: A physical therapist is using transcutaneous electrical nerve stimulation (TENS) for a patient with chronic low back pain. To activate the gate control mechanism for immediate pain relief, which parameter set is MOST appropriate?
- Low frequency (2–4 Hz), high intensity, long pulse duration (200–300 µs)
- High frequency (80–150 Hz), low to moderate intensity, short pulse duration (50–100 µs) (Correct answer)
- Low frequency (2–4 Hz), low intensity, short pulse duration (50–80 µs)
- High frequency (80–150 Hz), high intensity, long pulse duration (200–300 µs)
Correct answer: High frequency (80–150 Hz), low to moderate intensity, short pulse duration (50–100 µs)
Conventional (high-frequency) TENS at 80–150 Hz with short pulse duration activates large-diameter Aβ fibers, stimulating the gate control mechanism at the dorsal horn to inhibit pain signal transmission. This produces immediate but short-lasting analgesia and is the classic 'gate control' application.
Question 2: A patient is receiving therapeutic ultrasound over the right bicipital tendon region. The physical therapist notes the patient's skin overlying a recent surgical metallic staple. What is the MOST appropriate action?
- Continue treatment but reduce intensity by 50%
- Switch to pulsed mode to eliminate thermal effects
- Discontinue ultrasound and select an alternative modality (Correct answer)
- Increase the treatment frequency to 3 MHz to limit depth of penetration
Correct answer: Discontinue ultrasound and select an alternative modality
Metal implants in the direct treatment field are an absolute contraindication to therapeutic ultrasound because the metal can concentrate acoustic energy, causing localized overheating and tissue damage. The therapist must discontinue ultrasound regardless of mode or frequency and select a different modality.
Question 3: A physical therapist applies fluidotherapy to a patient's hand following a distal radius ORIF (3 months post-op, hardware retained). The patient reports comfortable warmth. Which of the following represents the PRIMARY therapeutic benefit of fluidotherapy compared to a paraffin bath at the same temperature?
- Greater depth of heat penetration into joint structures
- Ability to perform active exercise during treatment (Correct answer)
- Lower risk of thermal injury due to controlled air medium
- Simultaneous superficial cooling via convective air flow
Correct answer: Ability to perform active exercise during treatment
Fluidotherapy's primary clinical advantage over paraffin is that patients can perform active range-of-motion exercises during treatment, combining the benefits of heat and movement simultaneously. Depth of penetration is similar between superficial agents, and thermal risk depends on temperature settings in both cases.
Question 4: A physical therapist is treating a patient with urinary stress incontinence using neuromuscular electrical stimulation (NMES) to the pelvic floor. Which parameter is MOST critical for achieving a muscle-strengthening effect rather than a fatigue-reduction effect?
- Frequency of 2–5 Hz to facilitate endurance of slow-twitch fibers
- Frequency of 35–50 Hz to elicit a tetanic contraction of fast-twitch fibers (Correct answer)
- On:off ratio of 1:1 with continuous delivery
- Pulse duration below 50 µs to avoid sensory recruitment
Correct answer: Frequency of 35–50 Hz to elicit a tetanic contraction of fast-twitch fibers
To elicit a strengthening tetanic contraction, NMES frequencies of 35–50 Hz are required to produce smooth, fused contractions that recruit fast-twitch (type II) muscle fibers. Low frequencies (2–5 Hz) produce twitch contractions targeting endurance, which is appropriate for fatigue-reduction but not strengthening.
Question 5: A patient with a wound showing signs of delayed healing and bacterial biofilm is referred for adjunctive electrical stimulation. Which modality and polarity combination has the STRONGEST evidence for promoting antibacterial effects and attracting neutrophils to the wound site?
- Alternating current (AC) at the anode
- High-voltage pulsed current (HVPC) with the cathode over the wound (Correct answer)
- High-voltage pulsed current (HVPC) with the anode over the wound
- Interferential current (IFC) at carrier frequency of 4,000 Hz
Correct answer: High-voltage pulsed current (HVPC) with the cathode over the wound
High-voltage pulsed current (HVPC) with the cathode (negative pole) placed over the wound is supported by the strongest evidence for bactericidal effects and attracting neutrophils and macrophages in the early inflammatory phase of wound healing. The negative charge repels negatively charged bacteria and facilitates immune cell migration.
Question 6: A physical therapist is prescribing low-level laser therapy (LLLT) for a patient with lateral knee pain and delayed soft-tissue healing following a grade II LCL sprain. Which of the following represents an ABSOLUTE contraindication that would require the therapist to withhold treatment?
- Presence of a titanium tibial plate 4 cm distal to the treatment site
- Direct irradiation over the patient's closed eyes (Correct answer)
- Application over an area of reduced sensation
- Use of LLLT within 72 hours of the initial injury
Correct answer: Direct irradiation over the patient's closed eyes
Direct irradiation of the eyes with laser, even at low levels, is an absolute contraindication because laser energy can cause irreversible retinal damage regardless of power class. Protective eyewear for both the patient and therapist is mandatory. Metal implants outside the field, reduced sensation, and acute injuries are not absolute contraindications to LLLT.
NPTE-PT Test Test Therapeutic Modalities Application 1
A physical therapist is using transcutaneous electrical nerve stimulation (TENS) for a patient with chronic low back pain.
To activate the gate control mechanism for immediate pain relief, which parameter set is MOST appropriate?