Anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis has been increasingly identified as the second most common type of autoimmune encephalitis after anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. It presents with acute or subacute onset of epileptic seizures, anterograde amnesia, behavior disturbances, sleep disorders and hyponatremia. In most patients with anti-LGI1 encephalitis, immunotherapy is successful in treating the encephalitis. However, relapses, chronic epilepsy, cognitive declines and psychiatric problems have been reported in some cases. So far, prospective studies to evaluate its clinical outcomes still remain limited. In this project, the investigators will use clinical features and advanced paraclinical examinations to prospectively investigate the clinical outcomes and the associated factors in patients with anti-LGI1 encephalitis.