A special type of head stereotypies in children with developmental (?cerebellar) disorder: description of 8 cases and literature review.

The authors report eight children, who presented in the first year of life with isolated head stereotypies, that corresponded neither to the usual normal 'rhythmic habit patterns of infancy', nor to various types of abnormal repetitive head movements described in young children. Their head stereotypies closely resembled those described in bobble-head doll syndrome. The neurological status evidenced axial hypotonia, ataxia, oculomotor abnormalities, motor and language delay. The patients were followed for several years clinically and with video recordings. No single aetiology was found. Computed tomography (CT) or magnetic resonance imaging (MRI) show a congenital cerebellar abnormality in two children but no hydrocephalus. The outcome of these children showed in all but one patient a normal cognitive and psychosocial development, even though the head stereotypies are still present in six of eight patients and all remain significantly clumsy. The association of head stereotypies and motor delay should prompt a search for cerebellar congenital malformation. The outcome of those patients was much better than originally anticipated and these head stereotypies are not related either to mental retardation, or to psychopathology. The possible mechanisms involved are also discussed.