Reorganization of Directed Corticomuscular Network via Median Nerve Stimulation in Cervical Dystonia.

BACKGROUND

Cervical dystonia (CD) originates in dysfunctional sensorimotor integration, creating an urgent need for neuromodulatory interventions that recalibrate pathological corticomuscular circuits.

OBJECTIVE

The aim of this study was to investigate whether median nerve electrical stimulation (MNES) can serve as a novel, noninvasive therapy that specifically targets the abnormal corticomuscular network.

METHODS

We investigated high-density electroencephalography combined with synchronized electromyography (EMG) recordings from 17 patients and 17 healthy control subjects during MNES and sensory trick (ST) tasks. Source-localized cortical activity and muscle signals were integrated into a directional corticomuscular network, with connectivity quantified by phase transfer entropy.

RESULTS

MNES selectively suppressed pathological 4 to 8 Hz intermuscular coupling in patients, reorganized aberrant muscle synergy, and drove frequency-specific network reorganization: reduced beta-band outflow, decreased clustering coefficients, and prolonged the shortest path lengths across multiple frequency bands. Crucially, MNES enhanced hemispheric asymmetry in primary sensory cortex, supplementary motor area, and cerebellum. Operating predominantly in theta/alpha bands, MNES contrasted sharply with ST's gamma-band modulation.

CONCLUSIONS

These findings demonstrate that MNES restores corticomuscular network dynamics through multilever reconfiguration, attenuating pathological synchrony while facilitating adaptive circuit plasticity, thereby validating directed network analysis as a framework for circuit-targeted neuromodulation in movement disorders. © 2026 International Parkinson and Movement Disorder Society.