Bimanual asymmetric exercises reduce pathological mirror movements after stroke: a case report with disconnectome mapping

Involuntary mirror movements (MMs) may occur in the nonparetic hand after stroke events, accompanying voluntary movements of the paretic hand. These can interfere with unimanual dexterity and bimanual coordination, potentially impacting the performance of activities of daily living (ADLs). However, neither the changes in such MMs over time nor effective interventions for them have been sufficiently established. We recently treated a patient with right putaminal hemorrhage following a stroke, who presented with difficulties performing bimanual tasks (e.g. typing and washing hair) because of prominent MMs in the nonparetic hand accompanying movements in the paretic hand, despite mild upper-limb motor paralysis and ADL independence. To facilitate voluntary paretic hand movement while targeting independent control of both hands, we implemented a bimanual asymmetric exercises (BAEs), wherein the patient performed different motor tasks with each hand concurrently. This reduced the patient's MMs while improving bimanual coordination. Even when paretic upper-limb impairment is mild, and patients can perform ADLs independently, evaluations and interventions should be conducted, while remaining mindful that MMs in the nonparetic hand can reduce overall upper-limb performance. BAEs may represent an effective approach for reducing MMs.