RESUMO
Dystonia is a disorder of movement caused by involuntary, sustained muscle contractions affecting one or more sites of body, frequently causing twisting and repetitive movements, or postures. Dystonic movements and postures can produce a wide range of clinical presentations. Some distinguishing clinical features of dystonia can help the appropriate diagnosis of primary dystonia. The direction of contraction is almost consistent. Action dystonia and occupational dystonia are related to a movement or task-specific movement, respectively. Sensory tricks or gestes antagonistes are usually seen in patients with dystonia. Two types of tremors can be seen in patients with dystonia: a postural and/or action tremor that resembles essential tremor and a rhythmic expression of dystonic tremor. Sometimes dystonic tremor appears to be less regular and can be associated with myoclonus. Onset age of dystonia, body distribution and etiologies are important to correct diagnosis of primary dystonia. It is well known that the age of onset has important prognostic implications. This article highlights general concepts of phenomenology, classification that are relevant for the purpose a clinical diagnosis.