Evaluation of wrist joint proprioception by means of a robotic device

Stroke, Parkinson's disease and other neurological conditions often cause proprioceptive deficits which impact the neural control of movement. Proprioception, which is the sense of body awareness, is central to assess accurate interaction with external environment and when compromised it results in several limitations in the activities of daily living. On the other hand, clinical assessment of the impact of proprioceptive deficits on motor functions has been difficult to elucidate mostly for the lack of accurate measurement devices especially for multi-DoF. Haptic robotic interfaces can be exploited to quantitatively evaluate proprioceptive acuity. We introduce a new method based on the use of a three-DoF robotic device to deliver accurate wrist kinematics and perform fine measurements in order to assess wrist joint proprioceptive acuity. Research protocol consists of passive movement in single-DoF configuration providing variable amplitude position stimuli. Data were collected from a group of healthy subjects who were instructed to discriminate the difference between stimuli intensities. Results highlight the efficacy and intrinsic simplicity of the proposed method marking the milestone for further investigations and characterization of proprioceptive acuity in pathologies and age related degradation of sensory motor functions. Moreover the robotic system can be used to design patient-customized therapies based on the particular impairment level and evaluate after every session the effectiveness of the therapeutic exercise.