Atypical Postural Control Variability and Coordination Persist Into Middle and Older Adulthood in Autism Spectrum...

Postural control deviations remain largely unexplored in middle aged and older autistic adults. With the increased prevalence of neurodegenerative conditions and heightened fall risk, precise quantification of postural variability and coordination may provide valuable insights into aging associated neuromotor deviations in autistic adults. Forty-seven autistic and 48 non-autistic individuals completed static stance, anterior-posterior (AP), and mediolateral (ML) postural sway on a force platform. Center of pressure (COP) metrics were derived and interpreted using ANCOVAs for between-group comparisons and multilinear regressions for group  $\times$  age interaction. Correlations between clinical measures and COP variables that differentiated groups were explored. Compared to non-autistic individuals, autistic adults exhibited greater COP standard deviation (COP_SD) and COP trajectory length during static stance and demonstrated significant COP_SD-AP reductions in older age. Autistic adults also exhibited decreased COP range of motion (ROM) but increased ROM variability in the target direction during dynamic stance. Autistic adults' postural sway was jerkier during dynamic stance, and increased ROM variability during dynamic AP sway was moderately associated with lower verbal IQ in autistic adults. Our findings highlight persistent postural control deviations in middle aged and older autistic adults. Static and dynamic stance are differentially associated with unique profiles of postural control in ASD. Specifically, autistic adults demonstrated pronounced increases in postural sway variability during static stance, while reducing coordination during dynamic conditions. The extent to which postural control deviations found in autistic adults are predictive to the onset of neurodegenerative conditions and the severity of falls warrants future longitudinal research.