[Physiopathology of dystonia]

Dystonia is a movement disorder characterized by sustained twisting movements and muscle contractions and abnormal postures. Dystonia is a symptom present in many diseases of the central nervous system. Anatomical data reveal that dystonia appears in diseases involving the basal ganglia, diencephalon, brain stem and cerebellum. Physiological studies revealed an abnormal facilitation of polysynaptic reflexes at the brain stem level. A common pathogenic mechanism for dystonia must be found in order to delineate in effective treatment. From clinical and biochemical data we suggest that dystonia is produced by abnormal shift of the norepinephrine/dopamine neurotransmission in favor of norepinephrine in different brain areas.