Disentangling the Brain Basis of Autism Versus ADHD

Despite significant advances in understanding the biological basis of autism, clinical trials continue to rely on subjective clinical observation and caregiver report measures as their primary outcome measures. Objective and biologically based markers (“biomarkers”) for diagnosing and assessing response to therapies in autistic individuals are still needed. Electroencephalography (EEG) measures of brain waves offer a promising biomarker that can be reliably collected from children of different ages and cognitive abilities.

Despite significant advances in the exploration of EEG as a dependable biomarker, there remains little research on how the presence of co-occurring conditions can impact these EEG biomarkers in young autistic children. This is especially important because up to 60% of autistic individuals also have co-occurring conditions, such as attention-deficit hyperactivity disorder (ADHD). Importantly, although ADHD and autism share many common features and may have shared genetic and neurobiological indicators, previous EEG studies suggest that there are unique patterns of brain activity that differentiate these diagnoses.

To explore these differences and to uncover another reliable biomarker for autism, the Duke Center for Autism is working to understand these unique patterns.
Neuroscientist Kimberly Carpenter, PhD, leads a multidisciplinary Duke Center for Autism and Brain Development research team studying how co-occurring ADHD symptoms influence patterns of EEG activity and examining whether variations in levels of social abilities are correlated with individual differences in patterns of EEG. Clarifying the extent to which ADHD symptoms influence underlying brain activity has important implications for addressing difficulties with identifying reliable brain-based biomarkers in autism, a highly heterogeneous condition.
 

“As clinical trials seek to demonstrate the effects of various therapies and supports on brain function, it is critical to understand the different patterns of neural activity in autistic individuals with and without co-occurring ADHD,” explains Carpenter. “We are working to clarify the link between such patterns and children’s behavior and specific symptoms, and ultimately therapy response. Our work could help clinicians and researchers who need to have objective ways of measuring the interventions and supports provided to autistic people.”