Quantification of instability of tone production in embouchure dystonia.

INTRODUCTION Musician's dystonia is a task-specific loss of voluntary motor control of the fingers or the embouchure. In contrast to pianists' dystonia, which can be objectively assessed based on movement kinematics and muscular activities, no objective quantitative measure has been established for embouchure dystonia. METHODS We focused on acoustic signals, and investigated, whether the fluctuation of the time-varying fundamental frequency of a note can provide an objective and reliable measure of embouchure dystonia. RESULTS A comparison between patients with embouchure dystonia and healthy controls found a significantly higher variability of the fundamental frequency for the patients. CONCLUSION The present findings propose a new quantification and objectivation method for embouchure dystonia.