Individualized Virtual Angle Offset Training for Patients with Stroke

Stroke is a leading cause of long-term sensorimotor disability, with upper limb deficits often persisting into the chronic stage. For many patients with stroke, the active muscle control zone, i.e., the angular range of typical muscle activation patterns, is reduced, leading to abnormal patterns and spasticity. When the displayed angle in a virtual environment is smaller than the actual angle, participants may implicitly perceive that their arm remains within the control zone. This discrepancy between visual and proprioceptive information may promote visuo-proprioceptive recalibration and sensorimotor adaptation. The current study included two preliminary investigations, one with healthy participants and one with participants with stroke, each divided into two groups (offset, control). Twenty-one healthy participants underwent a 30-min training session, after which they were tested with the actual elbow angle. Twelve hospitalized individuals with sub-acute stroke underwent three 30-min training sessions over one week. In both studies motion duration of participants who trained with an offset differed from motion of controls who trained with actual feedback. However, Fugl-Meyer Assessment upper limb scores in participants with stroke increased similarly for both groups. Additional testing is required to examine whether the method may be a potential direction for individualized impairment-based intervention.