Changes in the Functional Connectivity of Cerebellar Subregions in Anti-N-Methyl-d-Aspartate Receptor Encephalitis

Background: In anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis, the cerebellum, a characteristic brain region, exhibits abnormal functioning and structure. However, the relationship between resting-state activities in the cerebellar subregions and core symptoms of cognitive dysfunction is unclear. Methods: In this study, a total of 23 patients with anti-NMDAR encephalitis and 23 healthy controls were included, and 19 patients (mean age 30.05 ± 13.03 years) and 21 healthy controls (mean age 28.42 ± 9.47 years) were enrolled based on image quality and head movement. Seed-based functional connectivity (FC) analysis was used to investigate changes in FC of cerebellar subregions, and the association between changes in cerebellar subregion FC and cognitive dysfunction was explored in conjunction with cognitive scales. Results: Patients with anti-NMDAR encephalitis exhibited poorer cognitive performance than the healthy controls did. In the patient group, the FC between the right cerebellar Crus I and the left thalamus was significantly reduced and showed a negative correlation with disease duration (p < 0.05); however, it showed positive correlations with attention and information processing speed according to Symbol Digit Modalities Test (p < 0.01), as well as with verbal learning and memory (according to California Verbal Learning Test (CVLT; p < 0.05). The FCs between the left cerebellar Crus Ia and the right medial superior frontal gyrus, as well as between the left cerebellar Crus Ib and the right middle temporal gyrus, were decreased. The connectivity between the cerebellar vermis Crus II and the left putamen, along with the opercular part of the inferior frontal gyrus, showed a significant reduction. Decreased FC between the left cerebellar X lobule and the left putamen showed positive correlation with CVLT (p < 0.01). Conclusion: Cerebellar subregion and brain abnormalities FC in patients with anti-NMDAR encephalitis are linked to cognitive deficits. These results provide insights into the neurophysiological mechanisms underlying cognitive impairment in these patients.