# Spatial signature of low-frequency network changes accounts for pallidal stimulation outcome in cervical dystonia

## TL;DR

This study shows that changes in low-frequency brain activity during pallidal DBS correlate with treatment outcomes in cervical dystonia patients.

## Contribution

The study identifies a specific low-frequency cortical signature linked to DBS effectiveness in cervical dystonia.

## Key findings

- A low-frequency electrophysiological signature explains variance in DBS improvements across patients.
- Negative power changes in motor areas and positive changes in prefrontal and cerebellar regions were observed.
- Low-frequency power modulation is proposed as a mechanism of effective DBS beyond the basal ganglia.

## Abstract

Pallidal deep brain stimulation (DBS) has remarkable effects in patients with cervical dystonia. Yet, its neurophysiological mechanisms are not fully resolved to date. Converging evidence suggests that pallidal DBS modulates sensorimotor and cerebellar network activity in dystonia, possibly by disrupting pathologically enhanced low-frequency oscillations in the basal ganglia. Still, anatomical and electrophysiological findings have rarely been linked, and it is unclear whether oscillatory changes occur in the same network identified in neuroimaging studies.

In this cross-sectional study, we investigate the effects of pallidal DBS in patients with cervical dystonia using magnetoencephalography recordings on and off stimulation. We correlated DBS outcomes to the whole-cortex pattern of DBS-induced power changes in each cortical vertex.

This analysis revealed a distinct low-frequency electrophysiological signature that accounted for significant amounts of variance in DBS improvements across the cohort. The signature was characterised by negative peaks within the supplementary motor area and the motor cortex as well as positive peaks in prefrontal and cerebellar areas.

Our study sheds light on the cortical and cerebellar effects of pallidal DBS on a whole-cortex level and puts emphasis on low-frequency power modulation as a mechanism of effective stimulation beyond the basal ganglia in patients with cervical dystonia. Our findings might inform DBS programming and targeting as well as non-invasive stimulation strategies in the future.

10.13039/501100001659Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—Project-ID 424778381—TRR 295.