EEG abnormalities were observed in 66 (64.1%) patients, including 30 patients with anti-NMDAR encephalitis (62.5%), 19 patients with anti-LGI1 encephalitis (67.9%), 12 patients with anti-GABABR encephalitis (60%), and 5 patients with anti-CASPR2 encephalitis (71.4%).The most common EEG manifestations were focal and diffuse slow waves, and epileptic discharges were observed during the seizures. The gene discussed is CNTNAP2; the disease is encephalitis.