Analysis of EEG features of neuronal surface antibody associated encephalitis

Abstract

Objective To summarize the clinical manifestations, EEG and head MRI features of neuronal surface antibody associated encephalitis, and to investigate the role of EEG in determining the relapse or fluctuation of this disease, characteristics of EEG corresponding to head MRI, and EEG features in different clinical stages. Methods A total of 23 patients with neuronal surface antibody associated encephalitis were divided into ascent, climax, descent and recovery stage according to their clinical course. The relation between EEG background activity, distribution of slow wave, epileptiform discharge, extreme delta brush (EDB) and relapse or fluctuation of the disease was analyzed. The relation between EEG features and head MRI abnormalities, and also EEG features in different stages were analyzed. Results There were 19 anti-N-methyl-D-aspartate (NMDA) receptor encephalitis patients, 3 anti-leucine-rich glioma-inactivated 1 (LGI1) antibody associated encephalitis and one anti-γ-aminobutyric acid B receptor (GABABR) antibody associated encephalitis. The frequencies of clinical presentations were psychological or cognitive dysfunction, epileptic seizure, conscious disturbance, speech dysfunction and movement disorder in descending order. Within 30.50 d from onset, 6 patients demonstrated slow wave background, of whom 2 relapsed or fluctuated; 5 patients had α rhythm background and none of them relapsed or fluctuated. In patients with anti-NMDA receptor encephalitis, the difference in first hospital stay (Z = -0.785, P = 0.433) and relapse or fluctuation (Fisher's exact probability: P = 0.155) between EDB group and non-EDB group was not significant. There was no apparent correlation between EEG background activities and head MRI abnormalities in different stages. In ascent and climax stage, EEG background activities were predominantly slow wave, and the distribution of slow wave was relatively broader. EEG background changed to α rhythm from descent stage and slow wave distribution decreased in recovery stage.  Conclusions Some presentations of EEG, such as early background activities may be correlated with disease relapse or fluctuation. The incompatibility of EEG and head MRI suggests the importance of functional examinations in patients with neuronal surface antibody associated encephalitis. EEG features vary in different stages.

DOI: 10.3969/j.issn.1672-6731.2016.09.010