Geste antagoniste effects on motor performance in dystonia—a kinematic study

Background: The kinematic effects of gestes antagonistes in dystonia have not previously been studied. Objective: A kinematic investigation of the influence of the geste in patients with organic and functional dystonia. Methods: Twenty-six patients with dystonia (23 organic, 3 functional) 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 (amplitude x frequency, coefficient of variation for amplitude and velocity, halts, and hesitations) were extracted using a customwritten MATLAB script. Performance with and without geste was compared using Wilcoxon signed ranks testing. Results: When patients with organic dystonia executed their geste, speed of movement (amplitude x frequency) increased (p<0.0001), and halts decreased (p = 0.008). A similar trend was observed in the functional group. Conclusions: Finger tapping is swifter and less halting with activation of a geste.