Background

The kinematic effects of gestes have not previously been studied. The mechanism(s) by which these sensory tricks modify dystonic movement is not well understood.

Objectives

A kinematic investigation of the geste phenomenon in patients with dystonia.

Methods

Twenty-three patients with dystonia associated with a geste were studied. Twenty-nine healthy controls also participated. Fifteen seconds of finger tapping was recorded by electromagnetic sensors, and the task was repeated with geste. Separable motor components were extracted using a custom-written MATLAB script. Performance with and without geste was compared using Wilcoxon signed ranks testing.

Results

Speed and fluency of finger tapping is impaired in dystonia. When patients executed their geste, speed of movement (amplitude x frequency) increased (p<0.0001), and halts decreased (p = 0.007).

Conclusions

That gestes improve not only dystonic muscle contraction but also the efficiency of voluntary movement suggests a broad influence at the premotor control stage.