[MRI in patients with dystonias and Tourette syndrome].

Recent developments in magnetic resonance imaging have provided further insights into the pathophysiology of movement disorders including dystonias and Tourette syndrome. Both structural and functional abnormalities have been described in dystonic patients, with a number of genotype-phenotype correlations. Interactions between the cerebello-thalamo-cortical and basal ganglia-cortex networks play a role in the penetrance and expression of dystonia. In Tourette syndrome, motor symptoms and behavioral disorders correlate with structural changes in limbic, motor and associative fronto-striato-parietal circuits of the brain. Both disorders may be related to subtle developmental abnormalities. Compensatory mechanisms may have either a positive or a negative effect (adaptive reactions or faulty activity).