Predictors of cognitive performance in idiopathic adult-onset dystonia

Cognitive dysfunction is increasingly recognised as a potential non-motor feature of the idiopathic adult-onset dystonia (IAOD) phenotype. However, evidence from large cohort studies is lacking, as previous research has been limited to small samples, leaving several questions unanswered. To investigate whether cognitive performance in IAOD is related to or independent of clinical and demographic factors. A total of 297 patients with IAOD from the Italian Dystonia Registry, unselected with respect to cognitive status, were assessed using the Montreal Cognitive Assessment (MoCA). Dystonia severity was expressed using the Global Dystonia Severity Rating Scale (GDRS), while anxiety and depression were measured using the Hospital Anxiety and Depression Scale (HADS). Linear regression models were computed to explore the associations between MoCA scores and clinical and demographic variables. The mean raw total MoCA score was 22.8 +/- 5.0, while the mean age- and education-adjusted MoCA score was 23.6 +/- 4.0. Older age, fewer years of schooling, longer dystonia duration, segmental or multifocal dystonia distribution, higher HADS-depression score, and family history of dystonia were significant independent predictors of lower MoCA scores. No independent associations were found between MoCA score and sex, GDRS total score, presence of sensory trick, or HADS-anxiety score. In patients with focal dystonia, MoCA scores were not related to the specific site of dystonia. Our findings provide novel evidence supporting cognitive dysfunction as an intrinsic feature of the IAOD phenotype and suggest a possible pathophysiological link between dystonia and cognition.