LAUSR

PURPOSE Anti-N-methyl-D-aspartate receptor encephalitis is produced by an autoimmune reaction against macromolecular structures that form ionotropic receptors for glutamic acid NR2A and NR2B subunits. Other important findings are the multiple clinical and paraclinical manifestations, among which the EEG stands out. We characterized EEG patterns and their association with functional disability and hospitalization time in patients with anti-N-methyl-D-aspartate receptor encephalitis admitted in our center. METHODS We performed a retrospective cohort study that included patients with anti-N-methyl-D-aspartate receptor encephalitis. We recorded the clinical and sociodemographic characteristics and initial scalp EEG data. Functional disability was evaluated at admission and follow-up using the modified Rankin scale. RESULTS Forty-five patients aged 15 to 80 years were included. An abnormal EEG was reported in 92.5% of patients. We identified six EEG patterns. The mean hospitalization time was 3.2 (±2.4) months. The higher modified Rankin scale at admission and the absence of parietal or temporal epileptiform activity were associated with more prolonged hospitalization, hazard ratio of 0.338 for each modified Rankin scale level (95% confidence interval 0.174-0.658, P = 0.001), 14.5, P = 0.017, and hazard ratio of 5.6, P = 0.009, respectively. CONCLUSIONS EEGs are frequently abnormal in patients with anti-N-methyl-D-aspartate receptor encephalitis. The lower modified Rankin scale at admission and the absence of some focal epileptiform activity may be associated with shorter hospitalizations.