Rehabilitation Paired with VNS for Motor Function Recovery

There are 6 follow-up timepoints in this trial: 1. Screening follow-up timepoint (V1): All participants will sign the informed consent form and receive pre-implant evaluation, including physical examination, brain magnetic resonance imaging, FMA-UE, WMFT, modified Ashworth scale, ect. 2. Surgery follow-up timepoint (V2): All participants will be implanted with the VNS system, including the G115R IPG and L312 lead. 3. Baseline follow-up timepoint (V3): There is a baseline evaluation 7 to 14 days after the surgery, then participants will be randomly assigned to VNS group or Control group. 4. Clinic rehabilitation follow-up timepoint (V4): Participants will receive standard clinic rehabilitation 3 days per week and lasting 6 weeks. Both active VNS group (VNS group) and sham VNS group (Control group) will receive rehabilitation. Participants will be evaluated at the last day of this follow-up timepoint. 5. Home exercise follow-up timepoint (V5): Participants will take standard home exercise everyday in 6 weeks. Both active VNS group (VNS group) and sham VNS group (Control group) will receive rehabilitation. At the last day, after evaluating, group assignment is unblinded. 6. Unmasking follow-up timepoint (V6): In this 6 weeks, all participants will receive active VNS. Participants in VNS group will still take standard home exercise, and participants in Control group will receive standard clinic rehabilitation again. Participants will be also evaluated at the last day of this follow-up timepoint.