Developing a Low Cost Tool for Muscle Strength Assessment in Telehealth
Background: The manual muscle test (MMT) is used by numerous healthcare practitioners including nurses, physical therapists, occupational therapists, and physicians to assess muscle strength on physical exam and is graded on scale of 0-5. However, the MMT lacks interrater reliability, sensitivity in grading antigravity muscle strengths, and ability to be conducted in a telehealth visit. Our team sought to design an accurate, cost-effective, and accessible device for assessing and recording muscle strength that can be used reliably without provider assistance.
Methods: A limited literature review was conducted to identify current methods and tools used to assess muscle strength in clinical practice. Devices such as hand-held dynamometers were found to show high reliability in test populations, but had significant cost-associated barriers to widespread implementation. A team of subject matter experts in specialties including mechanical engineering, neurology, physical therapy, and physical medicine and rehabilitation were consulted to assess the practicality of our team’s device in both clinical and telemedicine settings. Throughout this review, a method of measuring muscle strength in tension was identified as clinically useful and economically feasible.
Results: A first generation prototype with the ability to measure forces generated by each muscle traditionally evaluated during the MMT has been designed by our team. Using readily available products including a trigger action clamp, a luggage scale, and a hook and loop strap our team produced a device that allows the user to independently and accurately measure isometric muscle strength in pounds.
Conclusion: We anticipate the standardized, accessible, and objective assessment of muscle strength provided by our device will serve as a new indicator of health in clinics that currently rely on the MMT. We also expect a reduction in need for in-person physical therapy sessions and follow ups for chronic medical conditions, making healthcare more accessible for those with limited mobility.
Reflections: The ability of our team to produce a working prototype while limited by current COVID-19 regulations indicates the feasibility of production, distribution, and use of an independent muscle strength assessment tool.
Sponsorship: This research was conducted by a team of students at the University of Texas without external funding.