To identify the spectrum of sleep disorders in the patients diagnosed with limbic encephalitis associated with anti leucine rich glioma inactivated protein 1 (LGI1) antibody.

Thirteen patients were identified with limbic encephalitis associated with LGI1 antibody in the Department of Neurology, Peking Union Medical College Hospital between December 2012 and August 2017. The characters of the 13 cases were studied from several aspects such as clinical presentation, imaging, polysomnography, cerebrospinal fluid and serum.

Serum test and/or cerebrospinal fluid test showed LGI1 antibody positive in all the 13 patients. Clinical presentation included: cognitive impairment, seizures, neuropsychiatric features. Sleep disorders presented in all patients, including insomnia, dream enactment behaviors, hypersomnia, involuntary movement. Polysomnogram in the 13 patients revealed that sleep efficiency decreased in 10 patients (<80%) , N3 sleep decreased in 10 patients, rapid eye movement sleep decreased in 13 patients; period limb movement disorder was identified in seven patients, period limb movement index was 15.6-224.4/h, four of the seven patients also had frequent irregular motor activity; six patients had frequent faciobrachial dystonic seizures (20-83 times throughout the night); rapid eye movement sleep behavior disorder (RBD) was diagnosed in three patients. Sleep disorder resolved almost completely in 10 of 13 patients who received immunotherapy.

Sleep disorders are cardinal manifestations of limbic encephalitis associated with LGI1 antibody, including insomnia, RBD, hypersomnia, involuntary movement. They may respond favorably to immunotherapy.

Limbic encephalitis; Sleep disorders; Polysomnography; Antibodies