Analysis of cerebellar dysmetria associated with lithium intoxication

By contrast to the permanent cerebellar sequelae developing over the weeks following a lithium intoxication, the cerebellar dysfunction occurring in the acute phase is poorly documented. In this study, we analysed the fast and accurate wrist flexion movements and the associated electromyographic activities in 6 patients as soon as possible after a lithium intoxication and three months later. Movements were recorded before and after increasing the inertial load of the moving hand. During the acute phase of the disease, three patients performed dysmetric movements, which became hypermetric when the inertia was increased. In the three other patients, the overshooting of the target which was already observed in the basal condition (no load), was even larger when masses were added. In all the patients, addition of loads increased the onset latency of the antagonist activity during the acute stage of the intoxication. Three of the six patients who presented fever, renal failure and did not undergo hemodialysis developed permanent cerebellar deficits. The three others who presented no fever, no renal failure and underwent hemodialysis recovered completely.