Upper limb rehabilitation with movement-sound coupling after brain lesions

Introduction/Background Recent studies showed that auditory feedback, sound and music can improve upper limb motor-recovery after stroke or Traumatic Brain Injury. However, the specific influence of different sound features and musical parameters has never been explored in this context. This study designed and tested different patterns of movement-sound coupling (sonification) that could stimulate arm movement during rehabilitation. Material and method Five sonification patterns were developed through a participative design process. These included two basic sound parameters, two musical extracts and environmental sounds. Upper limb movement was recorded using three Inertial Measurements Units placed on each upper limb. Movement analysis, sound-movement coupling and sound synthesis were performed using Max/MSP software (Ircam). The experimental protocol included three steps. (1) An interview to evaluate the sound universe of individuals (French Psychomusical Appraisal) and Evaluation of Amusia (Montreal Battery). (2) Sonification of two tasks: functional gestures and elbow extension, compared with the same tasks without sound. The two sides were examined, the less affected first. The IMU data were used to quantify the kinematics of arm movement. (3) A semi-directive interview to provide detail on the participant's subjective experience. Results At this stage, data has been obtained for 9 patients (stroke and TBI) and 7 healthy subjects. The subjective responses were positive, most of patients judged the sonification as interesting and stimulating. Most participants had a preference for environmental sound coupling. The observation of kinematic data showed large inter-individual differences and variable effects of sonification on movement amplitude, smoothness and velocity that varied between sides. Conclusion This study has established a novel sonification protocol which may be used to enhance and vary motor rehabilitation tasks. However, further analyses are needed, particularly on symmetry, before concluding on a quantitative effect of sonification. In addition, we need to examine the relationships between quantitative data and participants’ subjective experience.