Increasing the Repertoire of Intermuscular Co-ordination Post Stroke Through EMG-Guided Human-Machine Interaction

Inclusion criteria for aged matched healthy group * Male or female whose age range between 40 and 75 * no known neurological injuries Exclusion criteria for aged matched healthy group * have an orthopedic disorder involving upper limbs; * have a history of any neurologic disease; * have any history of epilepsy of the potential participants and/or their family members; * are unable to consent; * are pregnant. Inclusion criteria for stroke group * male or female hemiparetic chronic stroke survivors; * age ranging between 40-75 year; * with single unilateral ischemic or hemorrhagic middle cerebral artery stroke; * neurologically stable for \>6 months; * have an expectation that current medication will be maintained without changes for at least 3 months. Stable use of anti-spasticity medication (e.g., baclofen, diazepam, tizanidine) is accepted; * without severe spasticity (Modified Ashworth (MA) \<4); * have not received botulinum toxin on the impaired arm within 3 months. Exclusion criteria for stroke group * have an orthopedic disorder involving upper limbs; * cognitive impairment sufficient to interfere with informed consent or successful completion of the protocol (Montreal Cognitive Assessment (MoCA) score \< 26); * a history of another neurologic disease; * anesthesia of joint position sense in upper limbs; * are pregnant or have a chance that they might be (self-reported);