Isometric force pillow: using air pressure to quantify involuntary finger flexion in the presence of hypertonia

TL;DR

The paper introduces the isometric force pillow, a novel device that quantitatively measures involuntary finger flexion force in hypertonic patients, addressing the need for objective assessment tools beyond subjective scales.

Contribution

It presents a new, lightweight, computerized tool for quantifying involuntary finger grip force in hypertonic patients, enhancing clinical evaluation capabilities.

Findings

Provides a holistic measure of finger flexion force

Can be used in various orientations for testing

Offers a quantitative alternative to subjective assessments

Abstract

Survivors of central nervous system injury commonly present with spastic hypertonia. The affected muscles are hyperexcitable and can display involuntary static muscle tone and an exaggerated stretch reflex. These symptoms affect posture and disrupt activities of daily living. Symptoms are typically measured using subjective manual tests such as the Modified Ashworth Scale; however, more quantitative measures are necessary to evaluate potential treatments. The hands are one of the most common targets for intervention, but few investigators attempt to quantify symptoms of spastic hypertonia affecting the fingers. We present the isometric force pillow (IFP) to quantify involuntary grip force. This lightweight, computerized tool provides a holistic measure of finger flexion force and can be used in various orientations for clinical testing and to measure the impact of assistive devices.