Intact Sensorimotor Adaptation in Autistic Adults

Background: Atypical sensorimotor integration in autism leads to altered action models (Mostofsky & Ewen, 2011). There is growing evidence illustrating how atypical sensorimotor integration underlies differences in sensorimotor behaviour (Cook, Blakemore, & Press, 2013; Marko et al., 2015), however the majority of research has been carried out with autistic individuals that have mild severity, or require support. Whereas, autistic individuals who are moderate/severe, or require substantial support are understudied.

Objectives: Examine the effect of experience on sensorimotor adaptation in adults diagnosed with moderate/severe autism spectrum disorders.

Methods: Forty autistic individuals diagnosed with moderate/severe autism spectrum disorders formed an experimental group (n = 22) and a control group (n = 18). The experimental group participated in trampolining sessions and accumulated an average of 144 hours (SD =26) of sensorimotor experience. The control group, who were matched for age, gender, verbal IQ, social responsiveness, sensory profile, and motor proficiency, had participated in community-based activities that did not have a sensorimotor basis. A non-invasive preferential viewing protocol (PVP) measured gaze behaviour while observing one of four point-light models (8 seconds duration) displaying experimental stimuli: specialist trampolining movements (BAGA award level 2 seat drops and 3 twists) or the control stimuli: straight jumps on a trampoline, and gait. Participants viewed these on a computer monitor, while eye gaze was measured using a desk mounted Tobii X2 eye-tracker. A PVP trial required participants to view a vertical split screen, with the same action (e.g., seat drop) presented in an upright (congruent) and inverted (incongruent) orientation. Participants viewed each of the stimuli presented as a block of four trials, trial order within a block counterbalanced to avoid sequence effects. In total, there was 4 blocks and 4 trials. Preferential attention was quantified using first-fixation-location (e.g., congruent) and first-fixation-duration (Jones, Carr, & Klin, 2008; Ryan, Hannula, & Cohen, 2007).

Results: Significant group x congruency interactions were revealed for first-fixation-location (p = 0.001) and first-fixation-duration (p = 0.037) when viewing twists. The experimental group orientated attention to the incongruent point-light action, but then fixated longer on the congruent action (congruent: M = 193.85ms; incongruent: M = 147.63ms). The control group orientated attention to the congruent point-light action, but then fixated longer on the incongruent action (incongruent: M = 177.22ms; congruent: M = 169.00ms). No significant (ps > 0.05) effects were revealed when viewing seat drops, straight jumps, and gait.

Conclusions: Sensorimotor training leads to functional adaptation in the underlying perception-action system, with faster motor response times during the perception of learned stimuli (Catmur et al., 2009), and the development of experience-dependent perception-action processing (Calvo-Merino, Glaser, Grèzes, Passingham, & Haggard, 2005; Casile & Giese, 2006). Consistent with these effects, here there were differences found in preferential attention (first-fixation-location) and evaluation (first-fixation-duration) of specialist learned action stimuli (i.e., twists) following trampolining sensorimotor experience compared to those that engaged in community-based activities. This indicates intact sensorimotor development and processing in autistic adults diagnosed with moderate/severe autism spectrum disorders.