The Interaction of Cue Modality and Response Type: Audiovisual Integration Advantage or Visuomotor Disadvantage?

Background: Movement, coordination and multisensory integration are important components for communication and social interactions. There are known differences in the development of perception, communication and motor control in individuals with autism. However, there is little understanding as to how movement complexity and multisensory integration interact, and how the characteristics of a movement relate to communication skills in individuals with autism. Previous research has shown that young adults respond more quickly to visual versus auditory cues when performing eyes-only, key-press, and reach-to-point motor responses.

Objectives: The present study investigated if individuals with autism use similar movement control strategies when completing a multisensory-motor integration task. We predicted that integrating auditory information would be more challenging, leading to a larger difference between visual and auditory conditions.

Methods: Ten young adults with autism (Mean age 26.5years; 8 male/2 female; 10 right-handed) sat at a touchscreen monitor and EyeLink 1000plus gaze-tracker (500Hz). Participants were shown two potential visual targets (2degrees of visual angle; 16.5degrees from central fixation), and a subsequent central visual or auditory cue that identified the correct target. Participants responded either with: eyes-only, key-press, or a reach-to-point motor response. The two cue types and three response conditions were blocked and counter-balanced. Reaction time (RT) and movement time (MT) were collected using Experiment Builder (SR Research). Participants also completed the Broad Autism Phenotype Questionnaire, Raven’s Progressive Matrices, and the Peabody Picture Vocabulary Test to assess the effect of perceived social communication skills, pattern recognition, and vocabulary on movement and coordination, respectively.

Results: Saccade RT did not vary based on modality or condition. There was a significant effect of condition on Saccade MT with longer MT in the reach-to-point condition compared to the key-press condition, suggesting that additional time is required for the saccade when the task is more complex. There was a significant main effect of condition for Hand RT in which the reach-to-point condition had a significantly shorter hand RT than the key-press condition. Consistent with TD adults, movement planning, but not execution, was significantly influenced by knowledge of the limb. The reach-to-point condition also had significantly more trial-to-trial variability than the eyes-only and key-press conditions in Saccade RT and MT, and Hand RT, suggesting increased performance variability with an increase in task complexity.

Conclusions: When compared to previous research, adults with autism used similar movement strategies related to the three movement conditions. However, the overall advantage of visual cues for temporal measures of motor performance was not seen. The present results are consistent with evidence that visual-motor integration is more challenging for individuals with autism.