Usability study of wearable inertial sensors for exergames (WISE) for movement assessment and exercise.

BACKGROUND: Accurate assessment of movement limitations and compliance monitoring of exercises to restore movement are necessary to tailor treatments for individuals with motor deficits. Although several commercial-grade technologies are available to clinicians for evaluating movement limitations, they require one-on-one time-consuming assessments with limited reproducibility across care settings. To address these limitations, a wearable inertial sensors for exergames (WISE) system has been designed with: (I) an animated virtual coach to deliver instruction and (II) a subject-model whose movements are animated by real-time sensor measurements from the WISE system worn by a subject. This paper examines the WISE system's accuracy and usability for the assessment of upper limb range of motion (ROM). METHODS: Seventeen neurologically intact subjects were recruited to participate in a usability study of the WISE system. The subjects performed five shoulder and elbow exercises for each arm instructed by the animated virtual coach. The accuracy of ROM measurements obtained with the WISE system versus those obtained with the Kinect™ were compared using the root mean square error (RMSE) of the computed joint angles. The subjects additionally completed a system usability scale (SUS) to evaluate the usability of the virtual coach for tutoring ROM exercises. RESULTS: The absolute agreement between the WISE and Kinect devices was moderate to very good and it was limited because the Kinect sensor suffers from occlusion. The Bland-Altman limits of agreement for the exercises in the coronal and transverse planes were within the acceptable limits of ±10°. The SUS response data produced relatively high third and first quartile scores of 97.5 and 82.5, respectively, with the interquartile range of 15 and the minimum score of 65, suggesting that the subjects were interested in using the animated virtual coach for tutoring ROM exercises. CONCLUSIONS: An animated virtual coach-based WISE system for mHealth is presented, tested, and validated for guided upper limb ROM exercises. Future studies with patient populations will facilitate the use of these devices in clinical and telerehabilitation settings.

Wearable Inertial Sensors for Exergames and Rehabilitation.

This paper presents the design and development of an exergame for the wearable inertial sensor (WIS) system for performing range of motion (ROM) exercises. The salient features of the exergame include: (i) a sensor calibration user-interface (UI); (ii) a sensor mounting UI, (iii) a patient gaming UI; (iv) an instructor playback UI; and (v) an instructor exercise development UI. Along with the WIS system, the developed exergame UIs enable a user to perform ROM exercises in clinical and home-based environments. The exergame UIs can also be employed in a telerehabilitation setting for remote monitoring and assessment. Preliminary results on the efficacy of using the exergame environment is documented with: (i) sensor calibration time; (ii) sensor mounting and alignment time on the human body; and (iii) examination of user adherence to instructor programmed exercise routines.

Wearable Inertial Sensors for Range of Motion Assessment.

This paper presents the design and development of wearable inertial sensors (WIS) for real-time simultaneous triplanar motion capture of the upper extremity (UE). The sensors simultaneously capture in the frontal, sagittal, and horizontal planes UE range of motion (ROM), which is critical to assess an individual's movement limitations and determine appropriate rehabilitative treatments. Off-the-shelf sensors and microcontrollers are used to develop the WIS system, which wirelessly streams real-time joint orientation for UE ROM measurement. Key developments include: 1) two novel approaches, using earth's gravity (EG approach) and magnetic field (EGM approach) as references, to correct misalignments in the orientation between the sensor and its housing to minimize measurement errors; 2) implementation of the joint coordinate system (JCS)-based method for triplanar ROM measurements for clinical use; and 3) an in-situ guided mounting technique for accurate sensor placement and alignment on human body. The results 1) compare computational time between two orientation misalignment correction approaches (EG approach = 325.05 µs and EGM approach = 92.05µs); 2) demonstrate the accuracy and repeatability of measurements from the WIS system (percent deviation of measured angle from applied angle is less than ±6.5% and percent coefficient of variation is less than 11%, indicating acceptable accuracy and repeatability, respectively); and 3) demonstrate the feasibility of using the WIS system within the JCS framework for providing anatomically-correct simultaneous triplanar ROM measurements of shoulder, elbow, and forearm movements during several upper limb exercises.