Study on the relation of brain functional connectivity to movement disorders and cognitive impairment in patients with rapid eye movement sleep behavior disorder

Objective To explore the relation between abnormal functional connectivity of substantia nigra and impairment of movement and cognition in patients with rapid eye movement sleep behavior disorder (RBD).  Methods A total of 22 subjects, including 14 patients with RBD and 8 sex, age, education-matched healthy controls, were enrolled in this study according to international diagnostic criteria. Unified Parkinson's Disease Rating Scale Ⅲ (UPDRS Ⅲ) and Hoehn-Yahr Stage were used to evaluate motor function. Digit Ordering Test - Attention (DOT - A), Symbol Digit Modalities Test (SDMT), Stroop Color-Word Test (SCWT), Trail Making Test (TMT), Rey-Osterrieth Complex Figure Test (ROCFT), Clock Drawing Test (CDT), Boston Naming Test (BNT) and Auditory Verbal Learning Test (AVLT) were used to evaluate cognitive function. The functional connectivity from left and right substantia nigra to brain region were examined.  Results There were no statistical differences of UPDRSⅢ and Hoehn?Yahr Stage between 2 groups ( P > 0.05, for all). In comparison with control group, SDMT ( P = 0.001), ROCFT-copy ( P = 0.013) and AVLT-N2 ( P = 0.032) were significantly lower, while TMT-B test was significantly higher ( P =0.005) in RBD group. Compared with control group, the functional connectivity of right substantia nigra to left precentral gyrus ( P < 0.005) and right angular gyrus ( P < 0.005) were all decreased in RBD group.  Conclusions The results suggest that cognitive impairment occurs earlier than movement disorders in RBD, and there are abnormal functional connectivity from right substantia nigra to left precentral gyrus and right angular gyrus, proving that abnormal functional connectivity is the base of behavior disorders in RBD. DOI: 10.3969/j.issn.1672-6731.2017.09.005