Comparative behavioural and neurofunctional analysis of executive functions in adults with obsessive-compulsive disorder and attention-deficit/hyperactivity disorder using a virtual reality task

Abstract

This study aimed to examine executive functions (EFs) profiles across a sample of patients with obsessive-compulsive disorder (OCD) and attention-deficit/hyperactivity disorder (ADHD) employing ecological and performance-based measures of EFs and resting-state functional connectivity (rsFC) in the frontoparietal network (FPN) as predictors of the main outcome measures of a virtual reality (VR) test. Despite the clinical relevance of both disorders, direct comparisons of the EF profiles between OCD and ADHD remain limited. A total of 141 participants aged 18–56 years (56 diagnosed with ADHD, 39 with OCD, and 46 matched healthy controls) were evaluated using a Nesplora Ice Cream VR test and fNIRS-based rsFC from the FPN. The behavioural results indicated differences across the groups. Both ADHD and OCD patients exhibited notable impairments in planning when compared to controls; however, the OCD group’s performance was distinctly marked by a higher frequency of errors, potentially attributed to hypervigilance. While working memory deficits were observed in both groups compared to controls, their underlying mechanisms appeared to differ: in OCD, these difficulties might be linked from repetitive reference-checking behaviours, whereas in ADHD, they could be attributed to challenges in cognitive flexibility, which became increasingly pronounced during the task’s second phase. In terms of flexibility, the OCD group struggled to adapt to changes, whereas those with ADHD initially showed greater difficulties than controls but eventually recovered baseline accuracy. Furthermore, we found that processing speed was slower in patients with OCD compared to both patients with ADHD and controls. The VR task allowed for a detailed assessment of participants’ EFs performance. VR tests may offer a promising complement to more traditional assessment tools in clinical neuropsychology. The advantages and limitations of this approach were discussed. The findings aligned with evidence linking EFs to the rsFC of the FPN, highlighting the critical role of connections between parietal and prefrontal regions in supporting these processes.