Cognitive Impairment And Brain Imaging In Encephalitis Patients With Anti-leucine-rich Glioma Inactivated Protein 1 Antibody

Objective To investigated changes of cortex and hippocampus structure and cognitive function in patients with anti-leucine-rich glioma inactivated protein 1(LGI1)antibody encephalitis.Methods Thirteen patients with anti-LGI1 encephalitis and 15 normal controls(NC)were enrolled.Neuropsychological tests were performed to evaluate their clinical symptoms and cognitive function.Magnetic resonance imaging(MRI)data were collected,and surface-based morphometry was used to analyze the cortical changes and hippocampal volume.The correlation between brain structure changes and clinical symptoms and cognitive function was further analyzed.In addition,the support vector machine(SVM)was applied to classify the patients with anti-LG1 encephalitis from NC by using the cortical and subcortical hippocampal volume as classification characteristics.Results Montreal Cognitive Assessment Scale(Mo CA)(Z =-2.714,P = 0.007),Chinese Auditory Vocabulary Learning Test(CAVLT)-immediate recall(t =-3.545,P = 0.002),CAVLT-delayed recall(Z =-2.554,P = 0.011),CAVLT-recognition recall(Z =-2.442,P =0.015),verbal fluency test(VFT)-semantic score(t =-3.062,P= 0.005)were significantly lower than normal controls.Color digital connection test(CTT)-Digital completion time was significantly higher than NC(Z =-2.742,P =0.006).In anti-LGI1 encephalitis patients,the cortical thickness,cortical volume and bilateral hippocampal volume of right inferior frontal gyrus triangle were significantly lower than those of NC.Correlation analysis showed that in anti-LGI1 encephalitis group,the cortical thickness of the triangular part of the right inferior frontal gyrus was significantly positively correlated with VFT-semantics(r = 0.648,P = 0.023),and the volume of the left hippocampus was significantly positively correlated with CAVLTdelayed recall(r = 0.581,P = 0.048).Right hippocampal volume was positively correlated with Mo CA(r = 0.741,P = 0.006),CAVLT-immediate recall(r = 0.755,P= 0.005),CAVLT-delayed recall(r = 0.632,P = 0.027).Right hippocampal volume was negatively correlated with CTT-number(r =-0.598,P = 0.040).The cortical thickness,volume and bilateral hippocampal volume of right inferior frontal gyrus triangularis were used as the input features of SVM.The classification accuracy was78.57%,the sensitivity was 76.92%,the specificity was 86.67%,and the area under the curve(AUC)was 0.851.Conclusions Anti-LGI1 encephalitis patients have cognitive impairment such as memory,language and executive function,which is associated with gray matter volume atrophy in the triangle of right inferior frontal gyrus and bilateral hippocampus.The characteristic brain images of anti-LGI1 encephalitis patients can be used as indicators for early diagnosis,disease evaluation and prognosis prediction.