NPTE-PT Test Test Equipment and Therapeutic Modalities 1

Question 1

A physical therapist is treating a patient with acute lateral epicondylitis using therapeutic ultrasound. Which duty cycle setting would BEST minimize thermal effects while still delivering mechanical benefits to the tissue?

Accepted Answer

20% pulsed

Answer

A 20% pulsed duty cycle (1:4 on:off ratio) minimizes heat accumulation in tissue while still delivering non-thermal mechanical effects such as cavitation and acoustic streaming. Continuous (100%) and higher duty cycles generate significant thermal effects, which are contraindicated during acute inflammation.

Question 2

During iontophoresis for calcific tendinitis, a physical therapist uses acetic acid (acetate ion, CH₃COO⁻). Under which electrode should the medication be placed?

Accepted Answer

Cathode (negative electrode), because like charges repel the ion into tissue

Answer

Acetic acid dissociates into the negatively charged acetate ion. In iontophoresis, ions are driven into tissue by repulsion from the same-polarity electrode. Because acetate is negative, it is placed under the cathode (negative electrode), which repels it into the underlying tissue.

Question 3

A therapist applies interferential current (IFC) using two medium-frequency carrier currents of 4,000 Hz and 4,080 Hz. What beat frequency is produced within the tissue, and which physiological effect does this range BEST target?

Accepted Answer

80 Hz — pain modulation via gate control theory

Answer

The beat frequency in IFC equals the arithmetic difference between the two carrier frequencies (4,080 − 4,000 = 80 Hz). Beat frequencies in the 80–150 Hz range activate large-diameter Aβ sensory fibers, producing analgesia through the gate control mechanism.

Question 4

When applying a commercially prepared moist heat pack to a patient's lumbar spine, what is the recommended minimum number of towel layers between the pack and the patient's skin to prevent burns?

Accepted Answer

6–8 layers

Answer

Standard clinical guidelines recommend 6–8 layers of dry toweling between a hydrocollator moist heat pack and the skin. Hydrocollator packs can reach temperatures of 70–75°C (158–167°F), and this layering is necessary to reduce the surface temperature to a therapeutically safe range of approximately 40–45°C.

Question 5

A physical therapist orders whirlpool hydrotherapy for a patient with peripheral arterial disease (PAD) affecting both lower extremities. Which water temperature is MOST appropriate?

Accepted Answer

96–98°F (35.6–36.7°C) — near neutral warmth

Answer

Patients with PAD have impaired arterial perfusion and cannot meet elevated metabolic demands in ischemic tissue. Elevated water temperatures increase local oxygen demand while the compromised vasculature cannot increase supply, risking ischemic injury or ulceration. Near-neutral temperatures (96–98°F) allow gentle débridement benefits without imposing thermal stress.

NPTE-PT Test Practice Test

NPTE-PT Test Practice Test

NPTE-PT Test Test Equipment and Therapeutic Modalities 1