Sensory trick phenomenon improves motor control in pianists with dystonia: prognostic value of glove-effect

Jakobine Paulig,Michael Groãÿbach,Laurent Boullet,Hans-Christian Jabusch,Eckart Altenmã¼Ller

doi:10.3389/fpsyg.2014.01012

Abstract

Musician’s dystonia (MD) is a task-specific movement disorder that causes loss of voluntary motor control while playing the instrument. A subgroup of patients displays the so-called sensory trick: alteration of somatosensory input, e.g., by wearing a latex glove, may result in short-term improvement of motor control. In this study, the glove-effect in pianists with MD was quantified and its potential association with MD-severity and outcome after treatment was investigated. Thirty affected pianists were included in the study. Music instrument digital interface-based scale analysis was used for assessment of fine motor control. Therapeutic options included botulinum toxin, pedagogical retraining and anticholinergic medication (trihexyphenidyl). 19% of patients showed significant improvement of fine motor control through wearing a glove. After treatment, outcome was significantly better in patients with a significant pre-treatment sensory trick. We conclude that the sensory trick may have a prognostic value for the outcome after treatment in pianists with MD.

Highlights

Focal dystonia in musicians, known as musician’s cramp or musician’s dystonia (MD), is a task-specific movement disorder that manifests itself as a loss of voluntary motor control of extensively trained movements while the musician is playing the instrument (Jankovic and Shale, 1989; Frucht et al, 2001; Hallett, 2006; Altenmüller and Jabusch, 2008)
Mann-Whitney U tests showed significant improvement of fine motor control through wearing a glove in six cases in comparison with the baseline (19%; beneficial glove-effect; BGE; all p-values < 0.05), significant aggravation through the glove in nine cases (29%; all p-values < 0.05) and no significant effect in 16 cases (52%; both groups considered as displaying no beneficial glove-effect; no BGE)
The severity of MD at the time of baseline correlated with GE (Pearson’s r = −0.38; p = 0.03): the more pronounced dystonic symptoms were, the higher was the improvement with the glove

Summary

Introduction

Known as musician’s cramp or musician’s dystonia (MD), is a task-specific movement disorder that manifests itself as a loss of voluntary motor control of extensively trained movements while the musician is playing the instrument (Jankovic and Shale, 1989; Frucht et al, 2001; Hallett, 2006; Altenmüller and Jabusch, 2008) For those who are affected the disorder is highly disabling and often terminates their professional musical careers. A clinical sign, which emphasizes the important role of the sensory system as well as the sensory-motor integration in the pathophysiology of MD is the so-called sensory trick phenomenon This phenomenon is known from patients with cervical dystonia: touching the face contralaterally or ipsilaterally to the direction of head rotation may reduce or abolish involuntary muscle activity (Wissel et al., 1999; Schramm et al, 2004). Analog activation studies in patients with focal hand dystonia are not yet available

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