P68 Activation of the geste antagoniste improves speed of finger tapping in organic and functional dystonia

ObjectivesThe geste antagoniste is a typical feature of dystonia’s motor phenomenology. Gestes may also occur in functional dystonia. We investigated how gestes affect the kinematics of voluntary movement.DesignCross-sectional study.SubjectsTwenty-three patients with organic dystonia and three with functional dystonia were studied.MethodsFinger tapping was assessed while subjects wore electromagnetic sensors secured to index finger and thumb. Subjects were instructed to tap ‘as fast and as big as possible’ for 15 s, first with and then without activation of their geste. Precise position and orientation data, in six degrees of freedom, were recorded. Separable motor components were derived from a comparison of the x, y and z coordinates of each sensor. The product of amplitude and frequency, giving the sensor excursion per unit time, was used as a measure of average speed. A repeated measures ANOVA was conducted, with the factors CONDITION (with vs without geste), HAND (dominant vs non-dominant) and GROUP (organic vs functional).ResultsFor average speed, there was a significant effect of CONDITION—patients with both organic and functional dystonia performed better with geste (F1,24=13.5; p=0.001). There was no main effect of HAND or GROUP.ConclusionsGeste antagonistes enhance motor performance in organic and functional dystonia. These selective voluntary movements may have a general effect on the execution of motor plans in dystonia. Sample numbers were too small to allow meaningful analysis of GROUP effects.

Édouard Brissaud: distinguished neurologist and Charcot’s pupil

ABSTRACT Professor Charcot had several pupils in his famous neurological service at the Salpêtrière Hospital in Paris, France. Among them, Édouard Brissaud was one of Charcot’s favorite pupils, temporarily becoming his successor after Charcot’s death. Brissaud’s neurological contributions were significant, including the description of hemifacial spasm, “geste antagoniste” in dystonia, pseudobulbar affect, post-traumatic stress disorder, the Brissaud-Sicard syndrome, and Brissaud’s sign. Additionally, Brissaud was the first to suggest that Parkinson’s disease pathology could be related to the substantia nigra.

The occurrence of dystonia in upper-limb multiple sclerosis tremor

Background: The pathophysiology of multiple sclerosis (MS) tremor is uncertain with limited phenotypical studies available. Objective: To investigate whether dystonia contributes to MS tremor and its severity. Methods: MS patients ( n = 54) with and without disabling uni- or bilateral upper limb tremor were recruited (39 limbs per group). We rated tremor severity, writing and Archimedes spiral drawing; cerebellar dysfunction (SARA score); the Global Dystonia Scale (GDS) for proximal and distal upper limbs, dystonic posturing, mirror movements, geste antagoniste, and writer’s cramp. Results: Geste antagoniste, mirror dystonia, and dystonic posturing were more frequent and severe ( p < 0.001) and dystonia scores were correlated with tremor severity in tremor compared to non-tremor patients. A 1-unit increase in distal dystonia predicted a 0.52-Bain unit (95% confidence interval (CI) 0.08–0.97), p = 0.022) increase in tremor severity and a 1-unit (95% CI 0.48–1.6, p = 0.001) increase in drawing scores. A 1-unit increase in proximal dystonia predicted 0.93-Bain unit increase (95% CI 0.45–1.41, p < 0.001) in tremor severity and 1.5-units (95% CI 0.62–2.41, p = 0.002) increase in the drawing score. Cerebellar function in the tremor limb and tremor severity was correlated ( p < 0.001). Conclusions: Upper limb dystonia is common in MS tremor suggesting that MS tremor pathophysiology involves cerebello-pallido-thalamo-cortical network dysfunction.