Neurophysiological insights in dystonia and its response to deep brain stimulation treatment

Stephen Tisch,Patricia Limousin

doi:10.1007/s00221-020-05833-8

Abstract

Dystonia is a movement disorder characterised by involuntary muscle contractions resulting in abnormal movements, postures and tremor. The pathophysiology of dystonia is not fully understood but loss of neuronal inhibition, excessive sensorimotor plasticity and defective sensory processing are thought to contribute to network dysfunction underlying the disorder. Neurophysiology studies have been important in furthering our understanding of dystonia and have provided insights into the mechanism of effective dystonia treatment with pallidal deep brain stimulation. In this article we review neurophysiology studies in dystonia and its treatment with Deep Brain Stimulation, including Transcranial magnetic stimulation studies, studies of reflexes and sensory processing, and oscillatory activity recordings including local field potentials, micro-recordings, EEG and evoked potentials.

Highlights

Dystonia is defined by “sustained or intermittent muscle contractions that lead to abnormal movements, postures, or both” (Fahn 1988)
A study in 12 patients with generalised or focal isolated dystonia has shown a reduction of the excessive alpha oscillations over the motor cortex and interhemispheric alpha coherence during GPi or subthalamic nucleus (STN) DBS (Miocinovic et al 2018)
Microrecordings have confirmed that the low frequency activity recorded with LFP comes from the pallidal neurons and is relevant for the expression of the symptoms including real-time modulation of dystonic contractions by effective sensory tricks

Summary

Introduction

Dystonia is defined by “sustained or intermittent muscle contractions that lead to abnormal movements, postures, or both” (Fahn 1988). A study in 12 patients with generalised or focal isolated dystonia has shown a reduction of the excessive alpha oscillations over the motor cortex and interhemispheric alpha coherence during GPi or STN DBS (Miocinovic et al 2018). This support the role of network desynchronization in the effect of DBS. Microrecordings have confirmed that the low frequency activity recorded with LFP comes from the pallidal neurons and is relevant for the expression of the symptoms including real-time modulation of dystonic contractions by effective sensory tricks. Adaptive DBS approaches may differ for thalamic targets owing to added complexity of thalamic reorganisation in dystonia (Lenz et al 1999)

Conclusions

Compliance with ethical standards