Amplitude Modulation Frequency Comparison in Kilohertz Transcranial Magnetic Perturbation (kTMP) for Chronic Stroke

Inclusion Criteria: 1. Adults aged 18-80 years who have a history of a unilateral stroke ≥ 12 m prior to enrollment. 2. Fugl-Meyer Assessment: Upper Extremity (FMA UE) score 20-55. 3. Ability to communicate, understand, and give appropriate consent. Participants can follow two-step commands. 4. Motor evoked potentials in a hand muscle when stimulating ipsilesional cortex with suprathreshold single-pulse TMS (MEP positive). Exclusion Criteria: 1. Participants with moderate or severe cognitive impairment (MoCA \< 18). 2. Participants with sensory deficits FMA-S ≥ 6/12 (with proprioception ≥ 2/4). 3. Language impairment or behavioral disorder that interferes with their ability to adhere to the protocol or to provide informed consent. 4. Individuals who have a serious uncontrolled medical condition, including but not limited to severe cardiovascular and cardiopulmonary disease. 5. Pregnancy or plans to become pregnant during the study period. 6. Botulinum toxin injections of the affected upper extremity within 3 months prior to onset of study assessments/testing through the last visit. 7. Severe spasticity of the affected upper limb (Modified Ashworth ≥ 3). 8. Absolute contraindications related to non-invasive brain stimulation, including: History of seizures in the last 12 months while taking anti-epilepsy medication Presence of any metal implants in the head (excluding the mouth), such as cortical stimulators and DBS, clips, coils, shunts, stents or skull plates, cochlear implants Permanent eye liner or head tattoos Implanted electronics such as pacemakers, defibrillators, intrathecal baclofen pumps or vagus nerve stimulator History of experiencing a serious adverse event during a previous transcranial magnetic stimulation (TMS) session