Rhythmic Bilateral Movement Training Modulates Corticomotor Excitability and Enhances Upper Limb Motricity Poststroke: a Pilot Study

The recovery of coordinated motor function after stroke onset has been associated with the practice of upper limb movements that required the activation of homologous muscles. This pilot study investigated whether repetitive bimanual coordinated movements enhanced upper limb corticomotor (CM) excitability and motor function poststroke. Patients practiced driving their paretic wrist through passive rhythmical flexion-extension by active flexion-extension of their unaffected wrist using purpose-built manipulanda over a 4-week period. Both preintervention and postintervention motricity was assessed using the upper limb Fugl-Meyer rating scale, and cortical maps of wrist flexor and extensor representations were derived from potentials evoked by transcranial magnetic stimulation. Five of nine subjects improved upper limb motricity in response to this novel active-passive bimanual movement therapy (APBT). Unaffected cortical map volume decreased, especially for a subgroup of five patients who had a postintervention increase in motricity. No change in unaffected map volume was revealed for the four patients who did not improve their postintervention motricity. No consistent shifts in cortical map center of gravity were revealed. These findings suggest that APBT can initiate an improvement in motricity that is accompanied by a balancing of between-hemisphere CM excitability. The findings justify the assessment of the rehabilitative effects of APBT in a homogeneous sample of patients poststroke.