VR-based tasks reveal distinct cognitive profiles in stuttering and ADHD

Background

Stuttering and ADHD are sometimes assumed to share underlying cognitive features, particularly around attention and executive function. This assumption can lead to overlapping support approaches that may not serve either group well. Kazazi’s doctoral research aimed to determine whether the cognitive profiles of people who stutter and people with ADHD are genuinely similar or fundamentally different.

What the researchers did

Kazazi, supervised by Prof Peter Howell (principal supervisor) and Dr Daniela Romano (secondary supervisor) at University College London, recruited 179 adults across three groups: people who stutter, people with ADHD, and neurotypical controls. Participants completed a series of VR-based cognitive tasks designed to measure selective attention, divided attention, sustained attention, and working memory. Brain activity was recorded via EEG and eye movements were tracked throughout. Network Models (NMs) were the central analytic method, used to compare cognitive architectures across groups - an approach that examines how cognitive processes are interrelated rather than treating each measure in isolation. The VR environment provided a more ecologically valid assessment context compared to traditional computerized tests.

What they found

The cognitive profiles of people who stutter and people with ADHD were distinct across nearly every measure. People who stutter showed their greatest difficulties on auditory selective and divided attention tasks, suggesting that managing competing auditory information is particularly challenging. People with ADHD, by contrast, showed impulsivity-related patterns visible in their eye tracking data - patterns absent in the stuttering group. Working memory was involved in both groups but operated through different mechanisms. EEG data further confirmed that the neural signatures associated with each group’s attention challenges were qualitatively different.

Why this matters

These findings push back against the idea that stuttering and ADHD share a common cognitive foundation. By demonstrating distinct profiles, the research suggests that support approaches designed for one group should not be assumed to transfer to the other. The use of VR-based assessment also demonstrates how immersive environments can provide richer, more naturalistic data about cognitive function than traditional lab tasks.

Limitations

The study focused on adults, so the findings may not generalize to children, where developmental trajectories could look different. Participants with both stuttering and ADHD were excluded, meaning the study cannot speak to the genuinely co-occurring population. The VR tasks, while more ecologically valid than screen-based tests, still represent controlled laboratory conditions.