UNILATERAL ASTERIXIS AND FOCAL BRAIN-LESI ONS

Asterixis is a involuntary movement with spontaneous interruptions and intermittent muscle tone. It occurs during posture maintenance. It is usually bilateral and, in this case, is observed in metabolic encepha lopathy. Unilateral asterixis is more uncommon. We report 12 cases whi ch occurred in patients with focal brain lesions. In all cases asterix is involved the upper limb and the lower limb in only 2 cases. Asterix is was transient, discrete and always associated with other neurologic al signs. The causal lesions (7 infracts, 2 haematomas, 2 abscesses, 1 meningioma) were unique in 7 cases and multiple in 5. Asterixis was a lways contralateral to the unilateral lesions. Lesions mainly involved the thalamus (7 cases) and other structures (lenticular nucleus, fron tal lobe, internal capsule, precentral regions and cerebellum). The fr equency of thalamic involvement suggested dysfunction of the thalamo-c ortical loop.