High-frequency rTMS over supplementary motor or primary motor cortex on reach-to-grasp in Parkinson's disease: A randomised controlled trial
- Journal
- Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology (Q1)
- Published
- 11 September 2026
- Study design
- Randomized controlled trial
- Evidence level
- Level 1, High (CEBM 1b)
- Authors
- Jenjira Thanakamchokchai, Weerawat Saengphatrachai, Suweena Khacharoen, Pornpiroon Phuegsilp, Prachaya Srivanitchapoom, Yuvadee Pitakpatapee, et al.
- PMID
- 42754417
- DOI
- 10.1016/j.clinph.2026.2112404
Why clinicians should know about it
- Picked for Neurology (clinical) (top studies of the week, 20 September 2026): Randomised trial of HF‑rTMS in Parkinson's
Abstract
OBJECTIVES: This study investigated the effects of a single-session of high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) on reach-to-grasp (RTG) performance in Parkinson's disease (PD), comparing stimulation over the supplementary motor area (SMA), primary motor cortex (M1), combined SMA + M1, and sham stimulation. METHODS: Thirty-six individuals with mild-to-moderate PD were randomised into four groups (n = 9/group),each receiving a single 20-minute session of 10-Hz HF-rTMS. RTG performance under both barrier and non-barrier conditions, alongside cortical excitability and inhibition, was evaluated before and after stimulation. RESULTS: Under the non-barrier condition, RTG coordination demonstrated a significant group × time interaction, with improved association time lag only after SMA stimulation (P < 0.05). For RTG planning, the SMA group showed superior gains compared with sham across all conditions. Although no significant between-group differences were found for RTG execution, both the SMA and M1 groups exhibited significant within-group improvements in movement and deceleration times. Combined stimulation produced no additive or synergistic benefits, yielding outcomes comparable to single-site stimulation. All real stimulation groups demonstrated prolonged cortical inhibition. CONCLUSION: The SMA appears to be a superior target for enhancing RTG coordination and planning in PD, potentially acting as a neural bypass for dysfunctional basal ganglia-thalamocortical circuits. The absence of synergy in the combined protocol suggests homeostatic metaplasticity may limit multisite gains, highlighting the SMA as a "temporal orchestrator" and supporting target-specific rTMS tailored to kinematic deficits. SIGNIFICANCE: These findings establish the SMA as a promising target and support HF-rTMS as a viable adjunct therapy for motor rehabilitation in PD.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.