Priming theta burst stimulation intensity for improving arm recovery after stroke

Optimizing the Intensity of Priming Theta Burst Stimulation to Improve Hemiparetic Upper Limb Motor Functions After Stroke: a Randomized Controlled Trial

This trial will test whether low‑intensity priming intermittent theta burst stimulation helps people with chronic stroke regain better arm movement compared with conventional priming, nonpriming, or sham stimulation.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 100 (estimated)
• Ages: 18 Years to 75 Years
• Sex: All
• Sponsor: The Hong Kong Polytechnic University (Academic / other)
• Locations: 1 site (Hong Kong, Hong Kong)
• Trial ID: NCT06509789 on ClinicalTrials.gov

What this trial studies

This randomized controlled trial will enroll 108 adults with chronic unilateral ischemic stroke and moderate-to-severe upper‑limb impairment. Participants are randomly assigned to one of four groups (low‑intensity priming iTBS, conventional‑intensity priming iTBS, nonpriming iTBS, or double‑sham) and receive three stimulation sessions per week for four weeks followed by 60 minutes of standardized motor training each session. Outcomes include clinical upper‑limb motor tests and measures of cortical excitation/inhibition using TMS and EEG, with MRI used to confirm lesion location. The study compares a 55% RMT priming protocol plus 70% RMT iTBS against other priming intensities and sham to see which produces the best motor and neurophysiologic changes.

Who should consider this trial

Good fit: Adults aged 18–80 with unilateral upper‑limb motor dysfunction from ischemic stroke at least 6 months prior, residual function at FTHUE levels 2–6, able to undergo MRI and TMS, and able to provide informed consent are ideal candidates.

Not a fit: Patients with contraindications to TMS or MRI, recent (<6 months) or bilateral strokes, major comorbid neurological disease, or those with very minimal or no residual arm movement are unlikely to receive benefit from this protocol.

Why it matters

Potential benefit: If successful, the approach could offer a more effective noninvasive stimulation protocol to speed and enhance recovery of arm movement after chronic stroke.

How similar studies have performed: Previous small studies of iTBS and priming paradigms have shown mixed but promising effects on cortical excitability and motor recovery, while low‑intensity priming specifically remains relatively novel and less tested in large randomized trials.

Eligibility criteria

Inclusion Criteria

1. Unilateral upper limb motor dysfunction caused by ischemic stroke, with stroke onset≥6 months. Diagnosis will be verified using discharge summary and radiological reports issued by Hospital Authority. Qualifying participants will undergo structural magnetic resonance imaging (MRI) at the University Research Facility in Behavioral and Systems Neuroscience (UBSN) at PolyU to further confirm their lesion location in the period of experimental participation.
2. Age between 18 and 80 years.
3. Residual upper limb functions between levels 2-6 in the FTHUE, indicating moderately-to-severely impaired upper limb motor functions.
4. Capable of providing informed written consent. Exclusion Criteria

Patients who meet any of the following criteria will be excluded:

1. any contraindications to TMS (screened by the safety checklist by Rossi(33)) and/or MRI (screened by the MRI safety checklist offered by UBSN \[see supplement\]).
2. Diagnosed with any concomitant neurological disease other than stroke.
3. signs of cognitive impairment, with a Montreal cognitive assessment score\<21/22 out of 30 (34).
4. Severe spasticity in the hemiparetic upper limb muscles, with a Modified Ashworth score \> 2 (35).

Where this trial is running

Hong Kong, Hong Kong

• Jack Jiaqi Zhang — Hong Kong, Hong Kong, Hong Kong (Recruiting)

Conditions Stroke; Transcranial magnetic stimulation; Theta burst stimulation