Dystonia after head trauma.

Dystonia is a rare consequence of head trauma. We describe 10 such cases and review 19 similar patients reported in the literature. Twenty-two of the 29 patients suffered head injury during the first or second decade of life. There was a variable delay between the head trauma and the onset of dystonia. In 18 cases with severe head injury, this interval (median, 18 months; range, 1 month to 9 years) was longer than in 11 cases with mild head injury (median, 14 days; range, 3 days to 5 years). In our series, nine of the 10 cases started as a focal dystonia and one as a hemidystonia. The dystonia progressed and spread over several months or years. Two cases remained as focal dystonias, but the others developed segmental, hemi-, multifocal, or generalized dystonia. On brain imaging studies (CT or MRI), the most frequent lesion site was in the contralateral basal ganglia or thalamus, but two cases had normal brain scans. Dysfunction of the lenticulothalamic neuronal circuit seems to be related to the development of dystonia following head trauma.