Cognitive impairment in Chinese patients with isolated generalized dystonia: a case-control study.

Background: Previous studies have indicated that non-motor symptoms are primary problems in focal dystonia, but limited data are available about cognitive function and their correlation with motor severity in generalized dystonia (GD). Methods: In the present study, we performed a case-control study and enrolled isolated genetic or idiopathic GD patients and age-, sex- and education-matched healthy controls (HC). Clinical characteristics, motor symptoms, psychiatric symptoms, and cognitive performance were assessed in both groups using various standardized rating scales and a comprehensive neuropsychological battery. Group comparisons, multiple linear regression analyses, and correlation analyses were performed, with adjustment for demographic and affective variables and correction for multiple comparisons. Results: Twenty patients with GD and matched healthy controls were enrolled and completed the assessments. Compared with HC, GD patients showed mild impairments, particularly in MoCA, executive function/attention, spatial ability, some tests in memory and similarities while other cognitive function did not differ between patients and HC. After adjustment and multiple comparison correction, MOCA, MOCA, executive function/attention and episodic memory remained the most consistent deficits. Several other cognitive differences were no longer significant after correction. No significant associations were found between cognitive performance and motor severity or disease duration. Cognitive performance did not differ between genetic and idiopathic subgroups or between medication groups. Conclusion: GD is associated with mild and heterogeneous cognitive impairments, with only a subset of deficits remaining robust after adjustment. Cognitive performance appears largely independent of motor severity, disease duration, medication use, and disease etiology.