Sequence Learning in Minimally Verbal Children With ASD and the Beneficial Effect of Vestibular Stimulation

People with autism spectrum disorder (ASD) and especially the minimally verbal, often fail to learn basic perceptual and motor skills. This deficit has been demonstrated in several studies, but the findings could have been due to the nonoptimal adaptation of the paradigms. In the current study, we sought to characterize the skill learning deficit in young minimally verbal children with ASD and explore ways for improvement. For this purpose, we used vestibular stimulation (VS) whose beneficial effects have been demonstrated in the typical population, but the data regarding ASD are limited. We trained 36 children ages 6-13 years, ASD (N = 18, 15 of them minimally verbal) and typical development (TD, N = 18), on a touch version of the visual-motor Serial-Reaction-Time sequence-learning task, in 10 short (few minutes) weekly practice sessions. A subgroup of children received VS prior to each training block. All the participants but two ASD children showed gradual median reaction time improvement with significant speed gains across the training period. The ASD children were overall slower (by ~250 msec). Importantly, those who received VS (n = 10) showed speed gains comparable to TD, which were larger (by ~100%) than the ASD controls, and partially sequence-specific. VS had no effect on the TD group. These results suggest that VS has a positive effect on learning in minimally verbal ASD children, which may have important therapeutic implications. Furthermore, contrary to some previous findings, minimally verbal children with ASD can acquire, in optimal conditions, procedural skills with few short training sessions, spread over weeks, and with a similar time course as non-ASD controls. Autism Res 2020, 13: 320-337. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Minimally verbal children with ASD who received specially adjusted learning conditions showed significant learning of a visual-motor sequence across 10 practice days. This learning was considerably improved with vestibular stimulation before each short learning session. This may have important practical implications in the education and treatment of ASD children.