Aspects of Stereotypic Behaviour among Autistic Persons: A Study of the Literature

Autistic people often exhibit apparently meaningless behaviours. Many such behaviours occur in a pattern of constant repetition. Although not an exclusive symptom of autism, such stereotypic behaviour is common among people with autism and related disorders (Cohen et al., 1987). The criteria for classifying PDD (Pervasive Developmental Disorder) in the DSM-IV mention ‘restrictive and stereotyped patterns of behaviour, interests and activities.’ Stereotypic behaviour is striking. Examples are patterns of tapping, body movements such as body-rocking and swaying, certain set hand and arm movements, characteristic facial expressions and eye movements, and repeated vocalisations. Various terms describe this behaviour, including ‘abnormal stereotyped acts,’ ‘motility disturbances,’ ‘mannerisms,’ ‘ritualistic acts,’ ‘rhythmic habit patterns,’ and ‘blindisms’ or ‘autisms’ (Lovaas et al., 1987). Most articles about stereotypic behaviour concern the mentally handicapped. The DSM-IV mentions that approximately 75% of children with Autistic Disorder function at a retarded level. Other authors mention higher percentages, namely 80% to 90% (Kraijer, 1991; Demeyer, 1976, 1979). Dutch research indicates that about a third of the population of institutions for the mentally retarded suffer from a Pervasive Developmental Disorder (Kraijer, 1991). Many findings about stereotypic behaviour among the mentally handicapped have played a role in conceptions about such behaviour among autistic people or people with a related disorder. This literature study is part of an investigation about the functions of stereotypic behaviour among autistic people or people ASPECTS OF STEREOTYPIC BEHAVIOUR AMONG AUTISTIC PERSONS: A STUDY OF THE LITERATURE