Measuring the Motor Aspect of Cancer-Related Fatigue using a Handheld Dynamometer

Cancer related fatigue severely impacts patients health related quality of life. Currently, researchers and clinicians rely on self reported questionnaires to diagnose this debilitating symptom. Methods outlined in this work help to standardize physical fatigue measurement in an accurate and objective manner.

This technique is fairly simple and easily adaptable for clinical use. Protocols provided in the current work will decrease the need for in person trainings for clinicians. Demonstrating these procedures will be Jeniece Regan, Sarah Alshawi Josephine Liwang and Jamell Joseph, postback fellows from our lab.

In a quiet room, set up a chair with armrests. Turn on the handheld dynamometer. When prompted, press the button to accept the calibration prompt.

Ensure the devices resting on a flat surface during calibration. The handle device is sensitive to mechanical force. It is important to handle the device with care.

Sit the subject in an upright position, with their feet in full contact with the floor. And hips as far back as the chair supports. Ensure the subject's hip and knee angles are close to 90 degrees.

And shoulders are a neutral abduction adduction and neutrally rotated. Ensure the subject's elbow is flexed at 90 degrees and the wrist is unsupported. Instruct the subject to grasp the dynamometer with the dorsal Intermediate phalanges facing forward.

Adjust the grip position to the subjects hand size. And then record the grip position. It is important to remember to ensure the proper seating and grip position throughout the tests.

Using a standardized script for each subject, explained that for this test, the subject will squeeze as hard as they can for five seconds. It is important to ensure that subjects maintain their maximal voluntary isometric contraction or MVIC during the static fatigue test. Count down three, two, one, Go.On Go, start the program by clicking the Go button on the dynamometer.

Repeat the MVIC test twice more for a total of three trials with 30-second rest between trials. Using a standardized script, instruct the subject to exert full effort for the whole 35 seconds of this test. Count down three, two, one, Go.On Go, start the program by clicking the Go button on the dynamometer.

For 35 seconds, use a standardized script to encourage the subject to squeeze hard. End the test after 35 seconds. Prepare a transparency overlay for the dynamometer screen.

Draw a horizontal line on the transparency that represents the target value, 50%of the subjects MVIC. Draw a second line 10%below the target value. Ensure the subject can see the screen and the 50%MVIC line.

Instruct the subject to maintain the target value for as long as possible. Count down three two, one, Go.On Go, start the program by clicking the Go button on the dynamometer. When the force declines by 10%from the target value for more than five seconds, stop the test.

Set the metronome to one beat per second. Then start the metronome. Instruct the subject that they will be performing a maximal squeeze every second for a duration of 30 seconds.

In time with the metronome, count down three, two, one Go.On Go, start the program by clicking the Go button on the dynamometer. Stop the test after 30 seconds. This study provides three different methods for measuring cancer related fatigue.

The dynamometer data can be used to calculate fatigue indices. Static fatigue, index version one represents the difference between the actual force generated and the hypothetical force in the absence of fatigue. Version two represents the decline in force from the first five seconds to the last five seconds.

While both versions detect the differences between fatigued and non fatigued subjects, version one resulted in better discrimination and a higher test to retest reliability. Version one is recommended for measuring fatigue in patients with Cancer. For the sub maximal fatigue index, performance is calculated as the total work.

Non fatigued subjects exhibited higher endurance and total work performed than fatigued subjects. While this test is typically not used to calculate voter fatigue ability, it is included because it is often used to induce fatigue and it better approximates daily tasks. The dynamic fatigue index represents the decline in the intermittent contractile force from the first five seconds to the last five seconds.

It also capture the difference between fatigued and non fatigued subjects. But the difficulty of it adhering to a consistent rhythm, introduces variability. Furthermore, while it has good test retest reliability, in prior studies, it did not demonstrate sufficient discriminative power.

Following this procedure, subjective fatigue can be measured using a self report questionnaire. The contribution of physical fatigue to the overall sense of tiredness can be further investigated using this procedure. Furthermore, physical fatigue data can be collected over time to examine longitudinal treatment effects.

Clinicians will be be able to objectively measure cancer related fatigue. In addition, researchers will be able to explore possible pathogenic mechanisms that underlies debilitating symptom.