Development of Restricted and Repetitive Behaviors from 2-19: Stability and Change in Repetitive Sensorimotor, Insistence on Sameness, and Verbal Behaviors in a Longitudinal Study of Autism.
Nina Masjedi, Elaine B Clarke, Catherine Lord
PMID 38743152WHAT IT FOUND
Restricted and repetitive behaviors in autism do not follow a single path.
Most children showed declining repetitive motor behaviors, while insistence on sameness often increased then plateaued or declined. Verbal repetitive behaviors surged as language developed, then stabilized.
Key findings
01The two-factor structure of ADI-R restricted and repetitive behaviors (repetitive sensorimotor and insistence on sameness) remained consistent into early adulthood, but adding a third factor for verbal behaviors significantly worsened model fit.
02Repetitive sensorimotor behaviors generally declined from ages 2 to 19, though a high-fluctuating group (27.3%) saw symptoms increase until age 9 before declining.
03Verbal restricted and repetitive behaviors increased sharply from ages 2 to 9 in the high-increasing group (46.46% of the verbal subsample) before plateauing from ages 9 to 19.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTsWhat it means for SLPs
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What it does not show
The sample was recruited in the early 1990s, meaning participants were diagnosed when autism was less common and criteria were different, which may not reflect the presentation of individuals diagnosed today. The sample had a high prevalence of language delays, which prevented the analysis of verbal RRB factor structure at ages younger than 9. There were very few female participants, preventing analysis of gender differences in RRB trajectories. Attrition and missing data occurred, particularly among African American participants and those with lower caregiver education.
Declared interests
Funded by the National Institute of Child Health and Human Development and the National Institute of Mental Health and Neurosciences. No other conflicts of interest were declared.
The easy way to misread this
Do not assume that all restricted and repetitive behaviors decline with age. While repetitive motor behaviors often decrease, insistence on sameness and verbal repetitive behaviors may increase during middle childhood or remain stable into adulthood, so a reduction in one type of RRB does not predict improvement in others.