Assessment of Throwing Patterns in Young Adults Diagnosed with Low-Expressive Language Autism and Severe Communication Disorder

Objectives There are a significant number of reports documenting movement differences and disorders in individuals diagnosed with autism spectrum disorders (ASDs). Observations of throwing patterns of young adults with low-expressive language ASD (LEL-ASD) have not been previously reported and may offer a description of how aberrant movement patterns manifest among this older population. Methods Throwing patterns over four distances (1.52, 3.04, 4.56, and 6.08m) were compared between young adults with LEL-ASD (n=7, 18.9 +/- 1.8 years) and a matched control group (n=7, 19.6 +/- 0.5 years). Eleven reflective markers were adhered to specific anatomical locations on participants and a six-camera motion analysis system (120 Hz) tracked marker locations resulting in joint kinematics (trunk rotation, elbow extension velocity, arm slot angle at release) and ball metrics (velocity, trajectory). Three-dimensional stick-figure representations were qualitatively observed by three independent raters to score each throw for stepping and trunk action based on a previously reported throwing rubric. Results Across all distances, the control group threw with 100% accuracy compared to 67.7% for the LEL-ASD group. There were significant between-group differences for trunk rotation, arm slot angle, and ball velocity at the point of release as throwing distance increased. Kinematic analysis revealed a largely planar throwing motion that did not adjust for the LEL-ASD group. Conclusions Young adults diagnosed with LEL-ASD displayed altered overhand throwing patterns as compared to control participants. Kinematic results underscored the difference in throwing patterns and revealed a lack of accommodation to alter the throwing pattern as a function of target distance. These data reveal differences of movement patterns between LEL-ASD and typically developing participants, specifically actions requiring the synchronized coordination of upper and lower extremities.