Dystonia: clinical approach.

Dystonia refers to sustained and vigorous contractions forcing a body region into an abnormal position that is consistently present. Dystonic postures and movements can variably combine to produce a wide spectrum of clinical presentations. The movement can affect one, two or more body regions, as in focal, segmental or generalized dystonia. Dystonic movements display specific features that can be recognised by clinical observation, such as speed, consistency, predictability, variability and relationship with voluntary movement. Sensory tricks and gestes antagonistes are manoeuvres that specifically alleviate dystonic movements and postures, thereby providing diagnostic clues. The diagnosis of primary dystonia can be established by applying a simple diagnostic flow chart during neurological examination to guide further laboratory testing.