Case Report: A period-based upper limb rehabilitation program using a degrees-of-freedom constraint strategy in severe post-stroke hemiparesis.

Background: Severe upper limb hemiparesis after stroke is often characterized by impaired motor function, increased flexor tone, and abnormal motor coordination, resulting in limited functional reaching. Because reaching requires coordinated control of joints, conventional task-oriented training may not sufficiently address motor control deficits arising from excessive or poorly regulated joint degrees of freedom (DoF). This case report describes a period-based upper limb rehabilitation program incorporating a constraint strategy targeting DoF to facilitate motor recovery in a patient with severe post-stroke hemiparesis. Case description: A 50-year-old man with left upper limb hemiparesis secondary to right putaminal hemorrhage (163 days post-onset) presented with severe impairment (Fugl-Meyer Assessment for Upper Extremity motor score, 12 points) and spasticity (Modified Ashworth Scale 2-3 in shoulder internal rotators, elbow flexors, and wrist flexors). Insufficient selective motor control and increased spasticity resulted in a dominant upper limb flexion synergy pattern, limiting his ability to perform forward reaching. Therapeutic intervention: A structured, period-based program was implemented over 21 consecutive days (60 min/day) with a proximal-to-distal progression and progressive release of movement constraints from the shoulder to the elbow and then to the wrist and fingers. Gravity-load management and DoF constraints were provided using an arm support device and a wrist-hand-finger orthosis in the early periods. As proximal voluntary control emerged, the wrist-hand-finger orthosis was replaced by a dynamic finger extension orthosis. In addition, neuromuscular electrical stimulation was applied to facilitate selective muscle activation across training periods. Follow-up and outcomes: Spasticity of the paretic upper limb decreased progressively over the training period, with early reductions in proximal muscle tone followed by later reductions in distal spasticity. Improvements in passive joint range of motion and consistent reductions in joint pain were observed throughout the intervention. Subsequently, motor function improved, as reflected by an increase in the Fugl-Meyer motor score to 16 points, with reduced synergistic movement patterns and more controlled reaching during tasks. Conclusion: An upper limb rehabilitation framework incorporating a DoF constraint strategy may support the recovery of coordinated motor control through a structured, period-based approach in individuals with severe post-stroke hemiparesis.