The Role of handedness and extrainstrumental burdens on the course of musicians' dystonia.

Background: This study investigates the impact of extrainstrumental workload on musician's hand dystonia (MD) and its relation to playing ability by testing two hypotheses: 1) the dominant hand is more severely affected at dystonia-onset; 2) improvement during treatment depends on whether the dominant or non-dominant hand is affected.

Methods: 151 patients with dominant-hand MD and 92 with non-dominant hand MD were assessed regarding their playing ability at dystonia-onset (T0) and after treatment (T1).

Results: There was no significant difference in playing-ability at onset between groups. Significant improvement and a greater change in playing-ability was observed in the dominant-hand group. We found no difference in the proportional frequency of right-handed and left-handed individuals in the group of patients affected on the right or left side respectively.

Conclusion: These findings suggest that handedness does not influence MD localization, but the prognosis is more favorable for those with dominant hand dystonia, potentially due to metaplasticity effects.