Severe autism and ADHD traits might both result from a smaller than average brainstem, according to research presented in October at the 2019 Society for Neuroscience annual meeting in Chicago, Illinois.
Brittany Travers, an assistant professor of kinesiology at the University of Wisconsin-Madison, led the research, and acknowledged that scientists “still don’t know much about the brainstem, and many studies have omitted it from their analyses.” She believes the results of the study “suggest that it may be helpful in understanding the neurobiological basis of individual differences in symptom severity, both in autism and ADHD.
For their research, Travers and her team screened 105 children between ages 6 and 10. 41 of the children had autism, while 25 met the criteria for ADHD. Another 34 had neither autism nor ADHD, while 30 had a condition with some genetic overlap with autism, such as bipolar disorder, or had a close relative with autism or schizophrenia. The children were given questionnaires to assess the severity of their autism and ADHD traits.
The researchers found that the children with the most severe autism traits also tended to have severe ADHD traits. Using magnetic resonance imaging (MRI), the researchers calculated the volume of each child’s brainstem. The children with smaller brainstems tended to have more severe autism and ADHD symptoms than those with larger brainstems, the researchers discovered.
Travers says these findings are only a first step, and said she plans to investigate the reasons for the size differences, and their consequences for overall brain function.