Cerebellar magnetic stimulation increased beta power and phase synchronisation in spinocerebellar ataxia type 3.

OBJECTIVE

Spinocerebellar ataxia type 3 (SCA3) is the most common autosomal dominant ataxia, with no cure currently available. Although repetitive transcranial magnetic stimulation (rTMS) over the cerebellum improves ataxia severity, its efficacy in SCA3 remains suboptimal. This study aimed to investigate the neurophysiological mechanisms underlying cerebellar rTMS in SCA3 using resting-state Electroencephalography (EEG).

METHODS

We conducted a sham-controlled study in SCA3 patients, recording resting EEG before and after a 3-week course of cerebellar rTMS or sham treatment. EEG power and functional connectivity were analyzed to identify treatment-induced changes.

RESULTS

Active rTMS significantly increased beta power and synchronization between the occipital and centrotemporal regions. We also established the predictive value of these neurophysiology features in long-term improvement of ataxia. No such effects were observed in the sham group.

CONCLUSIONS

Cerebellar rTMS modulates beta oscillations and synchronization in SCA3, which may underlie its therapeutic effects.

SIGNIFICANCE: These findings provide mechanistic insights into rTMS action in SCA3, offering potential biomarkers for treatment optimization and efficacy prediction.