Bradykinesia — the slowness and smallness of movement that is one of Parkinson's most disabling features — is partly caused by the brain's motor area losing its ability to adapt and strengthen its connections (a property called plasticity). This study tested whether gently nudging the brain back into a healthier rhythm could fix that problem. Researchers combined two non-invasive scalp stimulation techniques: tACS (transcranial alternating current stimulation), which delivers a weak electrical current to drive the brain into a faster "gamma" rhythm, and iTBS (intermittent theta burst stimulation), a form of magnetic pulse therapy known to promote plasticity. Twenty people with Parkinson's and twenty healthy volunteers each had two sessions — one real, one fake (sham) — in a blinded, randomised design.
The results were striking: in Parkinson's patients, the sham session produced no brain or movement change, but the real gamma-tACS session restored motor cortex plasticity and improved a key inhibitory brain circuit (GABA-A). Finger-tapping movements became measurably faster and wider, and those brain changes predicted how much each person's movement improved. Crucially, the benefit lasted beyond the end of stimulation — not just during it.
What this means for patients: This is early-stage research (20 patients, one session, short follow-up), so it does not represent a treatment you can currently access. However, it is a well-designed proof-of-concept trial registered on ClinicalTrials.gov (NCT06297538), and it demonstrates for the first time that restoring a specific brain rhythm can produce measurable motor improvement in Parkinson's. Patients interested in brain stimulation research can ask their neurologist whether similar trials are recruiting near them.