Repetitive and stereotyped behaviors in neurodevelopmental disorders: an observational analysis of four diagnostic groups.

Background: Repetitive and Stereotyped Behaviors (ST) are one of the key features of autism spectrum disorder (ASD) and they frequently occur in children with developmental delay/intellectual disability or sensory deprivation, but they are also described in children otherwise typical. This study aims to describe and compare ST in children with different neurodevelopmental disorders and in children having stereotypies but no other medical diagnosis (primary stereotypies).

Methods: The study sample comprised children with autism spectrum disorder (ASD) developmental delay (DD), severe visual impairment (VI) and primary stereotypies (PS), aged between 2 and 12 years old. The characteristics of the ST (age of onset, frequency, duration, triggers, phenomenology) were collected from their clinical history. The children's caregivers completed the Repetitive Behavior Scalerevised (RBS-R) and the Child Behavior Checklist (CBCL) to assess the ST and to screen for behavioral problems, respectively. Data concerning family history and comorbidity were also collected.

Results: 87 children (ASD [n=23]; DD [n=21]; VI [n=20]; PS [n=23]) were assessed. Mean age of ST onset was before 24 months in the whole sample. Symptoms usually occurred more than once a day in all groups, but Self-Injurious Behavior (SIB) and ST were reported at higher scores on the RBS-R in Secondary group. Stereotypies lasted less than 5 minutes in all but VI sample, in which lasted longer. Stereotypies of locomotion were mostly reported in ASD, self-injurious behaviors in VI, upper limb stereotypies in PS and DD. Parents reported several repetitive behaviors on the RBS-R, while attention deficit and withdrawn behavior appeared to be the main findings of the sample in the CBCL. Finally, a high number of comorbidities and family history for neurodevelopmental disorders was found in all groups.

Conclusions: The study showed that some specific patterns of stereotypies could be identified in most groups of disorders. At the same time the behavioral profile of children with stereotypies shows a significant overlap among different groups. These preliminary results suggest that stereotypies are strongly linked to neurodevelopmental disorders, but their association needs to be clarified with further studies.