PRIMARY (PHYSIOLOGIC) STEREOTYPIES

Stereotypies are broadly defined as involuntary, patterned, coordinated, repetitive, non-reflexive, movements that are goal directed and occur in exactly the same way with each repetition. Movements come in a variety of forms and are often misdiagnosed. Since they occur in patients with autism, mental retardation, sensory deprivation, or neurodegenerative disorders, their early onset is a source of concern for parents and physicians. As will be emphasized, these movements frequently occur in otherwise normal individuals, i.e., physiological stereotypies. Physiological stereotypies imply an otherwise normal patient and suggest a developmental problem that may improve with maturation of the nervous system. Recognizing the existence of a more “typical” pattern of childhood movements, one can subdivide physiologic stereotypies into three groups; common (rocking, thumb sucking, lip or cheek biting), head nodding and complex arm and hand movements. The course of physiologic stereotypies including their phenotypic characteristics, associated problems, and outcome has not been well studied. The results of a chart review/telephone follow up investigation of 81 children (32 girls, 50 boys), aged 7 months to 21 years, with bilateral repetitive, fixed, involuntary, and readily suppressible movements of the arms, hands, and fingers will be presented. Their clinical characteristics and the chronic nature of this condition will be emphasized. The underlying pathophysiologic mechanism for stereotypies, especially in otherwise normal children, is unknown. Proposed biological mechanisms for stereotypies have ranged widely from psychological hypotheses to abnormalities within cortico-striatal pathways. Volumetric MRI measurements have suggested abnormalities of the frontal white matter and caudate nucleus. Therapeutic trials for physiological stereotypies are limited; preliminary results using a behavioral intervention have been encouraging.