Cerebellar Intermittent Theta-Burst Stimulation and Motor Control Training in Individuals with Cervical Dystonia.

Lynley Bradnam,Michelle McDonnell,Michael Ridding

doi:10.3390/brainsci6040056

Abstract

Background: There is emerging evidence that cervical dystonia is a neural network disorder with the cerebellum as a key node. The cerebellum may provide a target for neuromodulation as a therapeutic intervention in cervical dystonia. Objective: This study aimed to assess effects of intermittent theta-burst stimulation of the cerebellum on dystonia symptoms, quality of life, hand motor dexterity and cortical neurophysiology using transcranial magnetic stimulation. Methods: Sixteen participants with cervical dystonia were randomised into real or sham stimulation groups. Cerebellar neuromodulation was combined with motor training for the neck and an implicit learning task. The intervention was delivered over 10 working days. Outcome measures included dystonia severity and pain, quality of life, hand dexterity, and motor-evoked potentials and cortical silent periods recorded from upper trapezius muscles. Assessments were taken at baseline and after 5 and 10 days, with quality of life also measured 4 and 12 weeks later. Results: Intermittent theta-burst stimulation improved dystonia severity (Day 5, −5.44 points; p = 0.012; Day 10, −4.6 points; p = 0.025), however, effect sizes were small. Quality of life also improved (Day 5, −10.6 points, p = 0.012; Day 10, −8.6 points, p = 0.036; Week 4, −12.5 points, p = 0.036; Week 12, −12.4 points, p = 0.025), with medium or large effect sizes. There was a reduction in time to complete the pegboard task pre to post intervention (both p < 0.008). Cortical neurophysiology was unchanged by cerebellar neuromodulation. Conclusion: Intermittent theta-burst stimulation of the cerebellum may improve cervical dystonia symptoms, upper limb motor control and quality of life. The mechanism likely involves promoting neuroplasticity in the cerebellum although the neurophysiology remains to be elucidated. Cerebellar neuromodulation may have potential as a novel treatment intervention for cervical dystonia, although larger confirmatory studies are required.

Highlights

Cervical dystonia (CD) is a neurological disorder characterised by involuntary muscle contractions causing intermittent or sustained abnormal postures and/or tremor of the neck [1,2]
There is a pressing need to identify new treatment interventions that modulate brain neuroplasticity to target aberrant mechanisms resulting in CD
Recent evidence suggests the cerebellum is involved in the pathophysiology of CD [5,6,7]

Summary

Introduction

Cervical dystonia (CD) is a neurological disorder characterised by involuntary muscle contractions causing intermittent or sustained abnormal postures and/or tremor of the neck [1,2]. Painful and strongly associated with depression and reduced quality of life [3,4]. There is a pressing need to identify new treatment interventions that modulate brain neuroplasticity to target aberrant mechanisms resulting in CD. There is emerging evidence that cervical dystonia is a neural network disorder with the cerebellum as a key node. The cerebellum may provide a target for neuromodulation as a therapeutic intervention in cervical dystonia. Objective: This study aimed to assess effects of intermittent theta-burst stimulation of the cerebellum on dystonia symptoms, quality of life, hand motor dexterity and cortical neurophysiology using transcranial magnetic stimulation. Outcome measures included dystonia severity and pain, quality of life, hand dexterity, and motor-evoked potentials and cortical silent periods recorded from upper trapezius muscles.

Objectives

Methods

Results

Conclusion