Manual dexterity in children with autism spectrum disorder: A cross-syndrome approach

Background: Manual dexterity (MD) is important for performing most activities of daily living, and children with ASD show MD deficits. However, the specificity of MD deficits in children with ASD has not previously been examined. Similar to children with ASD, extant evidence suggests children with Fetal Alcohol Spectrum Disorder (FASD) and Attention-Deficit Hyperactivity Disorder (ADHD) also show MD impairments. The purpose of this study was to examine the specificity MD deficits in children with ASD using a cross-syndrome design. We examined dominant (D) and non-dominant (ND) hand performance using a relatively large sample of children with ASD, FASD, ADHD, and typically developing (TD) children. Method: Seventy-two right-handed children (7–17 years old) participated in this study. To examine MD, the 9-hole pegboard test was completed on the D and ND-hands. The fastest time of three attempts was recorded. HPA was defined as the percent difference between D and ND-hand times. Results: D-hand MD was significantly worse in children with ASD vs. typically developing (TD) children (p = 0.002). ND-hand dexterity was significantly worse in children with ASD vs. FASD (p = 0.049) and TD groups (p = 0.004). Hand performance asymmetry (HPA) was significantly lower in the FASD group compared to both the ASD and ADHD groups (p < 0.05). Conclusions: These results show that children with ASD show specific deficits in MD not observed in children with FASD or ADHD. Furthermore, HPA was found to be a sensitive measure to prenatal alcohol exposure. Neurobiological mechanisms of ASD and FASD are discussed.