3. Brain structure in autism and ADHD
Goal: To determine whether behavioral symptoms of autism and ADHD and their neurobiological underpinnings extend into the typical population and how age impact the autistic brain.
Results: The structural MRI findings and autism and ADHD self-report revealed that autism and ADHD symptom severity was correlated with GM volume in the left inferior frontal gyrus. Autism symptom-severity was correlated with the left posterior cingulate, ADHD with the right parietal lobe, right temporal frontal cortex, bilateral thalamus, and left hippocampus/amygdale complex. Symptom severity of both disorders form a continuum extending into the general population, but it seems to be an oversimplification to typify psychiatric disorders such as autism and ADHD solely as extremes of brain structure abnormalities. In a second study we determined whether we could replicate the autism related findings, but this was not the case. In a clinical study focusing solely on autism we included adults aged 30 to 80 to see whether at a later age there were still differences in various structural brain indices including structural connectivity. On many measures no differences between those with and without an ASD diagnoses were observed, except on white matter integrity measures. Here it also seems that there were different age-related differences in the ASD group that were suggestive for the accelerated aging hypothesis. However, given the small sample size this study first needs to be replicated.
Details: In the publication of Geurts, Ridderinkhof & Scholte, (2012) in JADD you can find all details for the first part. The other findings can be found in Koolschijn et al (2015; JADD), in Koolschijn & Geurts (2016; JADD), and in Koolschijn et al. (2016; Human Brain Mapping).
For a description of this project in Dutch see d’Arc onderzoek.