Certain temperamental characteristics may effectively differentiate attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) at an early stage. Accelerometers and observational methods provide key markers of toddler temperament, in addition to parental assessments.
Children with Attention Deficit Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD) share certain temperamental features, such as limited effortful control and excessive negative affectivity. While ASD and ADHD have similar temperamental factors, there are evident changes in the affected children’s behavior. High negative affect in children with ASD is reflected by high levels of sadness, fear, and distress. This study, published in the Journal of Autism and Developmental Disorders, assessed the associations between measures of temperament and ADHD and ASD symptoms. The study also observed accelerometer activity and exuberance levels at 18 months, followed by the symptoms of ADHD and ASD at 36 months.
The study sample comprised 54 children with elevated likelihood for ASD. At 18 months, it was discovered that a rise in accelerometer activity level was associated with an increase in observed activity level, r(41) = 0.34, p = 0.04, and parent-reported activity level, r(41) = 0.34, p = 0.02, suggesting construct validity in the rated activity measures. Increased accelerometer activity level was also associated with decreasing attentional focus as evaluated by parents, r(42) = 0.32, p = 0.03. Exuberant youngsters in the bubble task exhibited reduced fear as evaluated by their parents,r(42) = 0.29, p = 0.04.
The authors observed that an increase in inhibitory control was associated with a decrease in the symptoms of ADHD. An increase in attentional shifting was associated with a decrease in the symptoms of ASD. In the context of underlying behavior, increased discomfort was associated with increased ASD symptoms. A decrease in the symptoms of ASD and ADHD was related to increased infant soothability, but the relationship did not hold when the overlap of symptoms was controlled for.
The study demonstrated that, overall, specific behavior with underlying temperament factors is related in a distinctive manner to either ADHD or ASD symptoms. The study findings also demonstrate that certain temperament-related behaviors may help differentiate between early symptoms of ASD and ADHD. In addition to parent ratings, accelerometers and observations are important measures for toddler temperament. The parent ratings provided the strongest association between symptoms of ASD and ADHD and temperament. Interventions to reduce symptom expression could be individualized based on certain early behaviors.
Konke, L. A., Forslund, T., Nilsson-Jobs, E., Nyström, P., Falck-Ytter, T., & Brocki, K. (2022). How Does Temperament in Toddlers at Elevated Likelihood for Autism Relate to Symptoms of Autism and ADHD at Three Years of Age? Journal of Autism and Developmental Disorders, 52(3), 995-1006. doi:10.1007/s10803-021-05001-z