Spatio-temporal and kinematic analysis of pointing movements performed by cerebellar patients with limb ataxia.

Three patients with cerebellar limb ataxia and three age-matched controls performed arm-pointing movements towards a visual stimulus during an experimental procedure using a double-step paradigm in a three-dimensional space. Four types of trajectories were defined: P1, single-step pointing movement towards the visual stimulus in the initial position S1; P2, double-step pointing movement towards S1; P3, double-step straight pointing movement towards the second position S2; and P4, double-step pointing movement towards S2 with an initial direction towards S1. We found that the cerebellar patients, as well as the controls, were able to modify their motor programs, but with impaired timing, severe anomalies in the direction and amplitude of the changed movement trajectories and alteration of the precision of the pointing movements.

[Guillain-Barré syndrome of axonal type, Campylobacter jejuni infection and anti-ganglioside GM1 antibodies].

Infection by Campylobacter jejuni (C. jejuni) has been reported in 17 to 55 p. 100 of the GBS.

[Cognition disorders and parkinsonian syndrome: diffuse Lewy body disease?].

A 68 year old man developed progressive cognitive impairment with an akinetic-rigid syndrome which was atypically responsive to levodopa. The patient died after 18 months and the postmortem examination showed typical Lewy bodies in the substantia nigra and pale bodies in the cortex which were unlabelled by ubiquitin antibodies. This case is particular by the neuropathological examination (no immunoreactivity to antibodies against ubiquitin) and by the abnormal response to treatment (dystonia).

Planning and execution of pointing movements in cerebellar patients.

Twelve patients with cerebellar dysfunction including a limb ataxia and 12 age-matched controls performed pointing movements with an arm. In one condition, the task was a simple reaction time (RT) movement directed toward a spatially defined target. The other two conditions involved choice tasks in which the amplitude and direction of movement were varied.