Description of Motor Stereotypies in Adolescents and Adults With Autistic Spectrum Disorder

Motor stereotypies (MS) are highly prevalent in children with autism spectrum disorders (ASD) and, although they tend to decrease with age, may persist into adulthood. The primary objective of this study was to describe the frequency, severity, number, and types of MS in adolescents and adults with ASD, to retrospectively evaluate their evolution over time, as well as to examine their relationship with sociodemographic and clinical variables.

A sample of 90 adolescents and adults with ASD were included in a cross-sectional and retrospective study. Rojahn's Stereotypic Behavior Scale (SBS) was used to measure the frequency, severity, and types of MS, while the Achenbach System of Empirically Based Assessment (ASEBA) inventories were utilized to assess psychiatric comorbidity.

MS were observed in 86.5% of cases. The most frequent MS in adolescents and adults with ASD were complex hand and finger movements and pacing (both of which were the most persistent over time) and repetitive body movements (which decreased in periodicity over time). Other, more socially inappropriate MS diminished over time. A significant reduction in the frequency and severity of MS was observed. No correlation was found between age and frequency of MS, and no differences were observed between men and women. Individuals with ASD and intellectual disability (ID) exhibited more types of MS per case and more frequent MS than those without ID, although these differences were not statistically significant. The ASD group with psychopathological comorbidities showed greater frequency and severity of MS, as well as more types of MS per case.

MS decreased in frequency and severity over time but persisted in ASD, particularly those that are more specific to ASD. The most socially inappropriate MS tended to disappear. The presence of MS in adolescents and adults with ASD was not influenced by age or sex. Adolescents and adults with ASD and ID or psychopathological comorbidities exhibited a greater variety of stereotypies, with the psychopathological comorbidities group showing higher frequency and severity of MS. Understanding the characteristics of MS could aid in predicting their progression, designing more targeted treatments (if needed), and identifying phenotypic subgroups to facilitate the discovery of associated risk genes.