Center for ADHD
Time Variability

A Multi-Method Feasibility Study Investigating Reaction Time Variability in Autism Spectrum Disorder

PI: Leanne Tamm, PhD
Co-I: Darren Kadis, PhD; Jeff Epstein, PhD

The National Institute of Mental Health has recently adopted a transdiagnostic Research Domain Criteria (RDoC) for studying mental disorders to better understand basic dimensions of functioning underlying the full range of human behavior. Our research has clearly demonstrated that variability in response times on computerized response tasks, is one of the primary neurocognitive deficits among patients with ADHD. Similar deficits have been noted across other psychopathologies including Autism Spectrum Disorders (ASD). However, most of the existing research on this topic has involved examining ADHD and ASD separately. Moreover, the majority of this work has examined behavioral manifestations of reaction time variability (RTV) with no research on the neural signature of RTV across disorders. Our goal in this application is to collect neuroimaging data among children with ASD and typically developing controls to complement the neuroimaging data we have collected using children with ADHD. We will first explore the feasibility of collecting neuroimaging data in children with ASD. We will also explore whether reaction time variability may be a “transdiagnostic phenotype” – i.e., a behavioral or biological measure that mediates etiological mechanisms of disorders and psychiatric symptoms.

  • Aim 1: To document the feasibility of collecting functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) data in children with ASD.
  • Aim 2: To examine associations between specific neural circuits and RTV in individuals with ASD, ADHD, and TD.
    • Hypothesis: The neural signature of RTV in children with ASD will differ from TD; it is not clear how it will compare with ADHD. Most studies of RTV assume that heightened RTV reflects occasional lapses in attention, and the dominant neurophysiological interpretation suggests this variability is linked to intrusions of task-negative brain network activity during task performance.