Cerebellar repetitive transcranial magnetic stimulation attenuates essential tremor by modulating visuomotor network connectivity.

OBJECTIVE

To investigate the neurophysiological mechanisms underlying cerebellar repetitive transcranial magnetic stimulation (rTMS) in essential tremor (ET) using source-level electroencephalography (EEG) phase-locking value analysis.

METHODS

EEG recordings and clinical assessments of ET patients (n = 20) before and after 4-week bilateral cerebellar rTMS were studied and evaluated for correlations. Brain source activities were reconstructed using standardized low-resolution brain electromagnetic tomography (LORETA). Functional connectivity and local network metrics in the alpha band (8-13 Hz) were compared with those of healthy controls (n = 20).

RESULTS

ET patients had lower nodal efficiency in visual areas and reduced inter-regional occipital connectivity than controls. Local network metrics in the left superior occipital gyrus, left cuneus, and right fusiform gyrus negatively correlated with tremor severity and significantly improved with rTMS. Connectivity changes between the left inferior occipital gyrus (IOG) and superior parietal gyrus (SPG) and the right SPG and midcingulate cortex (MCC), strongly correlated with improvements in activities of daily living. Performance-related connectivity changes involved the left IOG-SPG, right SPG-MCC, and left middle occipital gyrus to the supplementary motor area.

CONCLUSIONS

Cerebellar rTMS may alleviate ET by reorganizing functional connectivity within the visuomotor network.

SIGNIFICANCE: Our findings provide preliminary mechanistic insights and potential biomarkers for ET treatment, pending validation in future sham-controlled studies.