Sensory reweighting issues implicated in postural control impairments observed among children and adolescents with autism

• In Event: 1-203 - The development of visual-motor integration during activities of daily living: From research to translation

Integrative Statement

Introduction:
An estimated 1 in 59 children in the U.S. have Autism Spectrum Disorder (ASD) (Baio et al., 2014). Children with ASD rely heavily on their visual environment for maintaining balance compared to typically-developing (TD) children, and yet still struggle to maintain stability (Hannett et al., 2016; Stins et al., 2015; Mache et al., 2016). Particularly under more difficult conditions (e.g., quiet standing with eyes closed), children with ASD have higher sway (Fournier et al., 2010). Currently, balance assessment is not part of the standard diagnostic process, and visuomotor integration assessment is typically limited to fine-motor tasks (e.g., Beery VMI). The body of work on visuomotor ability in ASD is still nascent and limited in scope; most studies focus on static balance. Given the critical role of postural control as a developmental building block to higher-order skills, we aimed to identify specific conditions under which children and adolescents with ASD and TD differed in their static and dynamic postural control.

Hypothesis:
We hypothesized that individuals with ASD would have lower static and dynamic postural control than TD individuals, especially when visual context was impaired or visuomotor integration was required.

Study Population:
We tested 30 participants with ASD and 30 age-matched TD children and adolescents ranging from 7 to 25 years old.

Method:
We conducted this study in community locations (e.g., schools, libraries, museums, clinics). To increase translational potential, we used portable, affordable technologies that produce quantifiable and objective data. Participants wore a mobile eye-tracking system and completed a quiet-standing task on a firm surface under three different visual conditions (eyes open, eyes closed, and eyes open with the head in a translucent dome) and a limits of stability task (LoS) via a balance-testing system with integrated force plate. A subset of 10 participants (5 ASD, 5 TD) also completed the three visual conditions of the quiet-standing task on a foam surface.

Results:
Individuals with ASD showed increased sway during the quiet standing task in comparison to TD individuals, especially in the absence of visual context. During the LOS task, individuals with ASD demonstrated decreased postural control (inaccurate movements to target positions) and increased time to complete task when compared to Individuals of TD. Participants with ASD also used fixation and saccadic eye movements in ways that were not efficient for supporting postural control. These data suggest that individuals with autism may be less able to engage in visual behaviors and sensory reweighting processes that support postural control when their preferred source of information is unavailable or incomplete.

Conclusions:
The real-world consequences of postural instability and inefficient use of visual information are myriad, and include risk of falls and injury, difficulty performing activities of daily living, and limited functional independence. Balance testing and intervention is not currently standard practice in most settings serving individuals with ASD, but given the level of impairment observed in our study and others, it may be warranted, especially for children or adolescents who struggle with motor control.

Authors

• Haylie L Miller, University of North Texas Health Science Center
  Presenting Author

• Gabriela M Sherrod, University of North Texas Health Science Center
  Non-Presenting Author

• Tiffany Horne, University of North Texas Health Science Center
  Non-Presenting Author

• Janci Burns, University of North Texas Health Science Center
  Non-Presenting Author

• Danielle Blankenship, University of North Texas Health Science Center
  Non-Presenting Author

• Monica Nguyen, University of North Texas Health Science Center
  Non-Presenting Author

• Nicoleta Bugnariu, University of North Texas Health Science Center
  Non-Presenting Author