Fig. 1

PSAD assessment set up and an example dataset. A The PSAD is designed as a handle, which attaches to a joint-specific orthosis, in this case: a hand orthosis. The patient's hand was comfortably fitted inside the orthosis using Velcro straps. The subject was seated in an armless chair with the investigated arm placed on a height-adjustable table. The shoulder was slightly abducted, the elbow semi-flexed and the forearm pronated. In this position, the wrist and hand extend slightly outside the edge of the table. The hand size (measured as the distance (cm) between the third knuckle and the middle of the wrist joint), orthosis size (small, medium, or large), and height and weight of the subject were also recorded and used for the optimization of the signal analysis. EMG was recorded from Flexor Carpi Radialis (FCR-green) and Extensor Carpi Radialis (ECR-yellow) muscles using bipolar surface adhesive electrodes. The experimenter moved the hand of the patient throughout the whole available wrist extension range of motion (ROM) at either a slow (< 20°/s) or a fast (> 300°/s) velocity. B The upper panel is an example of torque data collected during slow (blue) and fast (red) stretches. The red circle represents the point in the ROM where the stretch reflex mediated torque was obtained while the blue circle represents the corresponding point during slow trials where the passive stiffness component was obtained. The lower panel is the FCR rectified EMG data corresponding to the fast trial. Figure 1A has been modified from [38]