The Potential Yield of External Feedback via Movement Sonification in Physiotherapy.

Objectives: New strategies to improve the validity, reliability and responsiveness of strength assessment in physiotherapy are needed. The purpose of this thesis was to develop a new hand-held dynamometer using sonification as a type of external feedback to improve the current assessment of muscle strength via concentric manual muscle tests. Method: A hand-held dynamometer was tested in healthy subjects in a within-subject design to assess several joints to establish validity, reliability, responsiveness of peak torque, angle of peak torque and angular impulse. The device was tested with groups of testers with different characteristics. Sonification of manual muscle tests was used by physiotherapists with different experience levels to assess its effects on reliability, responsiveness and force production. A focus group with experienced physiotherapists who had used the device was performed to explore their perspective in using the prototype and how to facilitate its implementation in a clinical setting. Results: The prototype can retrieve reliable information regarding peak torque and angular impulse in both upper and lower limb joints by both experienced and inexperienced testers. The prototype demonstrated validity in retrieving peak torque data in upper and lower limbs joints but not angle of peak torque. Sonification generally improved reliability for most testers in both joints tested. An increase in force production in 50% of the inexperienced testers was also found. Physiotherapists were satisfied with the use of the prototype and suggested software and hardware improvements. Conclusion: A feasible hand-held dynamometer for physiotherapy was developed using low-cost parts. Acceptable levels of validity and reliability in different joints and with testers with diverse experience levels were demonstrated. The use of sonification in manual muscle tests appears to benefit manual muscle tests positively and might be helpful in the future for research and training purposes.