[Cognitive function and cerebral blood perfusion changes in patients with anti-N-methyl-D-aspartate receptor encephalitis].

Objective: To investigated cognitive and cerebral blood flow changes in a cohort of patients with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. Methods: Fifteen patients with confirmed anti-NMDAR encephalitis from the First Affiliated Hospital of Anhui Medical University and the First Affiliated Hospital of University of Science and Technology of China between June 2015 and February 2019 were included in the study. Meanwhile, another 15 healthy subjects were selected as controls. All participants underwent neuropsychological tests for assessment of the clinical symptoms and arterial spin labeling (ASL) of magnetic resonance perfusion imaging scan were employed to evaluate cerebral perfusion. Then the relationship between changed cerebral blood perfusion and cognitive function was evaluated. Results: Patients with anti-NMDAR encephalitis showed significantly reduced overall cognitive function (Montreal cognitive assessment (MoCA)) than healthy controls (26.5±2.5 vs 28.6±1.9, P= 0.015), they also exhibited poorer performance in immediate memory, recognition, attention, language and executive function than healthy controls ( P< 0.05). However, no significant differences in clinical symptoms, viability, mental state and mood were observed between the two groups ( P> 0.05). Patients with anti-NMDAR encephalitis showed significantly reduced total brain cerebral blood flow (CBF) compared with the healthy controls (0.949±0.028 vs 0.953±0.025, P= 0.001). Compared with the healthy controls, the patients had decreased CBF in triangular and opercular parts of bilateral inferior frontal gyrus and left central frontal gyrus, however, they showed increased CBF in the left inferior temporal gyrus and left fusiform gyrus (all P< 0.05). In NMDAR group, the CBF in left central anterior gyrus was negatively correlated with Stroop's Color Word-word ( r= -0.68, P= 0.005). The CBF in left spindle gyrus was positively correlated with Stroop's Color Word-word ( r= 0.62, P= 0.015) and completion time of color trail test-A ( r= 0.81, P< 0.001), respectively, however, it was negatively correlated with Chinese Auditory Verbal Learning Test-immediate ( r= -0.59, P= 0.020) and Verbal Fluency Test-animals ( r= -0.58, P= 0.024), respectively. Conclusions: Patients with anti-NMDAR encephalitis have prevalent cognitive deficits such as memory, language, attention and executive dysfunction as well as changes in blood perfusion, which may be related to cognitive deficits. Changes in cerebral blood perfusion can be used as indicators for early diagnosis, disease monitoring and prognosis evaluation of anti-NMDAR encephalitis. Improving the cerebral blood flow of patients may promote the recovery of cognition.