The aetiology of those movement disorders characterized by localized, involuntary intermittent, and repetitive muscular spasm remains obscure. They include spasmodic torticollis, writer's and other occupational cramps, and facial spasms. The obscurity is reflected in psychiatric and neurological classification. Some, or all, are frequently regarded as conversion symptoms, although they differ profoundly from those typical of that group, particularly in terms of prognosis. Secondly, some, or all, have been regarded as variants of dystonia musculorum deformans. Otherwise, they occupy an indeterminate or ‘miscellaneous' place in classification. If it could be shown that a substantial number of clinical characteristics are shared by those who exhibit localized spasmodic conditions, they could justifiably be regarded as a distinct nosological entity. This might reasonably be regarded as a step towards clarifying their aetiology.