Following enrollment, participants with a history of stroke greater than 6 months underwent 1 month of upper-extremity rehabilitation twice per week to rule out potential for recovery with rehabilitation therapy alone. Thereafter, each participant underwent surgical implantation of the VNS system. 1 months later, VNS was activated.

Following enrollment, participants with a history of stroke within 6 months underwent 1 month of upper-extremity rehabilitation twice per week to rule out potential for recovery with rehabilitation therapy alone. Thereafter, each participant underwent surgical implantation of the VNS system. 1 months later, VNS was activated.

Following enrollment, participants with a history of stroke within 6 months underwent 1 month of upper-extremity rehabilitation twice per week to rule out potential for recovery with rehabilitation therapy alone. Thereafter, each participant underwent surgical implantation of the VNS system.When the a history of stroke was exceeded over 6 months, VNS was activated.

Device implantation was done under general anaesthesia. A horizontal neck crease incision was created left of the midline at the level of the cricoid cartilage. After the vagus nerve was identified, the stimulation lead was wrapped around the vagus nerve. The lead was then tunnelled subcutaneously to the pulse generator device which was contained in a subcutaneous pocket in the pectoral region.

The outcomes includes each participant's Fugl-Meyer assessment scale (FM-UE) scores for each monthly visit. FM-UE scores range from 0 to 100 and the higher scores indicated better outcome of movement.

The outcomes includes each participant's the Arm Motor Ability Test (AMAT) for each monthly visit. AMAT scores range from 0 to 57 and the higher scores indicated better outcome of movement.