Eeg alterations in autoimmune encephalitis and their predictive value for prognosis

EEG alterations in autoimmune encephalitis and their predictive value for prognosis AIM: Autoimmune encephalitis (AE) is a rare disorder associated with high mortality if not treated promptly. EEG provides important data for early diagnosis. We aimed to investigate the relationship between EEG findings and both mortality and seizure prognosis in AE in this study. MATERIALS AND METHODS: Patients diagnosed with AE at our hospital between 2021 and 2024 were evaluated. Seizure characteristics, laboratory parameters, brain MRI, and EEG findings at admission were recorded. Follow-up EEGs at the 1st, 3rd, and 6th months were also analyzed. Control group consisted of patients presenting with their first-ever epileptic seizure. Demographic, laboratory, EEG, and MRI findings were compared between the groups. RESULTS: AE group included 21 patients, while control group had 33. Age and gender distributions were similar between groups. AE group has higher rates of abnormal MRI findings, severe background slowing, background rhythm abnormalities, epileptiform activity, and the coexistence of these findings on EEG at admission than controls. Among the seven patients who died in AE group, severe background slowing and epileptiform discharges were more prevalent both at admission and at the 1-month follow-up. These patients had higher median age, BMI, admission CASE and mRS scores, urea, sodium, and sedimentation levels, and lower albumin levels. No significant differences in laboratory, MRI, or EEG findings were found between patients with and without recurrent seizures after the subacute phase. However, patients with recurrent seizures had higher rates of presentation with epileptic seizures at admission and higher CASE and mRS scores. CONCLUSION: Early initiation of immunotherapy is associated with a better prognosis in AE. In this study, severe background abnormalities and epileptiform activity on EEG were more common in patients who died. Further researchs are needed to determine if earlier inititaion of more intensive immunotherapy in patients with such EEG abnormalities can improve their prognosis or not.