Sleep-related breathing disorders in auto-immune encephalitis.

<bold>Background:</bold> While neurological sleep disorders have been described in auto-immune encephalitis (AE), little is known about sleep-related breathing disorders (SRBD) in patients with AE although it may carry significant morbi-mortality. We aimed to describe the prevalence of SRBD and their management in a cohort of patients with AE. <bold>Methods:</bold> Cohort study including patients with AE, who underwent sleep interviews and nighttime video-polysomnography (V-PSG) with respiratory setup between 06/2019 and 10/2023. <bold>Results:</bold> Forty-six patients with AE were included, with a median age of 60 [40, 69] years and a BMI of 25.7 [23, 29]kg/m² at the time of V-PSG recording. Overall, 32 (70%) patients had SRBD. Identified SRBD were: sleep apnea syndrom (SAS) (n:22; 51%) with 15 having moderate/severe SAS (68%), nocturnal hypoventilation (n:12; 36%), irregular breathing (n;8; 17%), stridor (n:2; 4%), central hypoventilation (n=1; 2%) with overlaps between patients. Type of SRBD varied significantly between AE type (<italic>cf</italic>. figure 1). Nocturnal alveolar hypoventilation, was particularly prevalent in anti-IgLON5 (80%) and seronegative (43%) encephalitis. Positive airway pressure or noninvasive ventilation were initiated in 20 patients (43%). Death or AE relapse occured in 6 (13%) patients. <bold>Conclusion:</bold> Two-thirds of patients with AE have SRBD. Thorough overnight respiratory assessment during sleep including overnight capnography is needed in all patients with patients with AE <fig><object-id>erj;64/suppl_68/PA2677/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>