Cognition and metacognition in functional motor symptoms and functional seizures: A case-control study

BackgroundCognitive symptoms are common in functional neurological disorder (FND), yet there is inconsistent evidence of impaired neurocognitive test performance in this population. We aimed to assess core cognitive functions and global metacognition in patients with functional seizures (FS) and functional motor symptoms (FMS), and to explore relationships between cognition, metacognition, and cognitive symptoms in these groups. MethodsThis single-centre case-control study recruited participants with FS (n=50) and FMS (n=50), in addition to age- and gender-matched healthy controls (HC, n=50), and clinical controls with depression and/or anxiety disorders (CC, n=50). The Cambridge Neuropsychological Test Automated Battery was used to assess response speed, working memory, executive functions, and social-emotional processing, with subjective confidence rated for each test. Validated measures quantified intellectual functioning, performance validity, and global cognitive symptoms. FindingsImpaired performance was demonstrated in both FND groups for sustained attention (p=0.03-<0.001) and set-shifting (p=0.01-0.001), withstanding correction for response speed, education, intellectual functioning, and psychotropic medication. Performance validity was comparable between groups. The FND groups reported reduced confidence for sustained attention performance (p<0.001) and elevated cognitive symptoms (p<0.001). Executive performance deficits correlated with reduced test-specific confidence in FS/FMS (p=0.02-<0.001). In FMS, confidence for sustained attention correlated negatively with cognitive symptoms (p=0.002). Cognitive symptoms were associated with psychological/physical symptom load, quality-of-life, and/or general functioning in FND and CC groups (p=0.04-<0.001). InterpretationPatients with FS and FMS displayed deficits in executive functioning performance, with intact metacognitive awareness, alongside significant cognitive complaints. These neurocognitive features were associated with poorer clinical status, warranting interventions targeting cognitive control and/or cognitive symptoms in everyday life. FundingThis study was funded by a Medical Research Council Career Development Award granted to SP [MR/V032771/1]. This project also represents independent research part-funded by the NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and Kings College London.