Background: Several instruments have been proposed to investigate restricted, repetitive behaviors (RRBs) in individuals with Autism Spectrum Disorder (ASD). Systematic video observations may overcome questionnaire and interview limitations to investigate RRBs. This study aimed to analyze stereotypic patterns through video recordings and to determine the correlation between the number and appearance of RRBs to ASD severity. Methods: Twenty health professionals wearing a body cam recorded 780 specific RRBs during everyday activities of 67 individuals with ASD (mean age: 14.2 ± 3.72 years) for three months. Each stereotypy was classified according to its complexity pattern (i.e., simple or complex) based on body parts and sensory channels involved. Results: The RRBs spectrum for each subject ranged from one to 33 different patterns (mean: 11.6 ± 6.82). Individuals with a lower number of stereotypies shown a lower ASD severity compared to subjects with a higher number of stereotypies (p = 0.044). No significant differences were observed between individuals exhibiting simple (n = 40) and complex patterns (n = 27) of stereotypies on ASD severity, age, sex, and the number of stereotypes. Conclusions: This study represents the first attempt to systematically document expression patterns of RRBs with a data-driven approach. This may provide a better understanding of the pathophysiology and management of RRBs.

Twenty expert caregivers wearing a body cam recorded 1868 videoclips in 67 autistic subjects along a 3 months close follow-up. A team consisting of a senior child neuro-psychiatrist and a senior psychologist selected 780 of them as expressing repetitive behaviors (RB) and made an empirical classification according to components, complexity, body parts and sensory channels involved, with the aim to understand better the pattern complexity and correlate with autism severity. The RB spectrum for each subject ranged from 1 to 33 different patterns (average= 11.6; S.D.= 6.82). Forty subjects expressed prevalent simple pattern and 27 prevalent complex patterns. No significant differences are found between the two groups according to ADOS score severity. This study represents a first attempt to systematically document expression patterns of RB with a data driven approach. This may provide a better understanding of the pathophysiology, diagnosis, and treatment of RB.