Watch the video version of this episode on YouTube - https://youtu.be/P9VLLyDvjnM 

A physical therapist uses interferential current to provide pain relief for a patient with a low back injury. Which term BEST describes the frequency modulation used with this type of electrotherapeutic device?

1. Phase duration
2. Interpulse interval
3. Sweep
4. Amplitude

Transcript

Welcome back to the Scorebuilders’ Question and Answer Podcast! This podcast provides members of the Scorebuilders’ team with the opportunity to explore challenging multiple-choice examination questions with students actively preparing for the licensing examination. My name is Scott Giles and I will be your host for today’s journey.

Ready? Let’s go!

A physical therapist uses interferential current to provide pain relief for a patient with a low back injury. Which term BEST describes the frequency modulation used with this type of electrotherapeutic device?

1. Phase duration
2. Interpulse interval
3. Sweep
4. Amplitude

Interferential Current
Interferential current combines two medium frequency alternating waveforms that are biphasic. Interferential current is most often used for pain relief, increased circulation, and muscle stimulation.

The question is specifically asking the term used to describe the frequency modulation with this type of current.

Let’s explore each of the options:

Option 1 - Phase duration
Phase duration is the amount of time it takes for one phase of a pulse. The length of the phase duration must be sufficient to exceed the capacitance of the targeted nerve in order to cause an action potential. This parameter is typically measured in microseconds. Phase duration is not a measure of frequency. 

Option 2 - Interpulse interval 
The interpulse interval is the time (microseconds) between two successive phases of a pulse. Interpulse interval is not a measure of frequency. 

Option 3 - Sweep 
Interferential current typically employs a frequency sweep to constantly change the frequency in order to prevent nerves from accommodating to the signal. A frequency sweep is also referred to as rate scan and is expressed in a specific range measured in hertz.

Option 4 - Amplitude 
Amplitude refers to the magnitude of current. The peak amplitude must be large enough to exceed the threshold for the nerve or muscle cell. Amplitude controls are often labeled intensity or voltage and can be expressed in volts, microvolts or millivolts. Amplitude is not a measure of frequency.

The correct answer is Option 3

Let’s explore the all student data:
26% of students selected Option 1, Phase duration
7% of students selected Option 2, Interpulse interval
56% of students selected Option 3, Sweep, the correct response
11% of students selected Option 4, Amplitude

System Classification
This question is a Non-Systems question which represents approximately 14% of all exam items.

Content Outline Classification
This question is an Equipment, Devices, and Technologies; Therapeutic Modalities question which represents approximately 6% of all exam items.

Level Classification
This question is a Level 1 question since the question requires students to possess basic foundational academic knowledge. Remediation of Level 1 questions occurs through academic review of entry-level content using textbooks, review books, Basecamp, and flash cards.

Academic Focus Area
Looking to review related academic content? Check out pages 745-747, 748-749 in PTEXAM: The Complete Study Guide.

Thanks for joining us on the Scorebuilders Q and A podcast! See you next week!