Neuropsychological and Neuroimaging Examinations of Self-Reported Sleep Quality in Alcohol Use Disorder With and Without Korsakoff's Syndrome

BackgroundAlcohol use disorder (AUD) patients without Korsakoff's syndrome (KS) report a variable self-rated sleep quality. Their ability to accurately judge their sleep quality may be related to their alcohol-related cognitive deficits and brain damage. KS patients, who present severe brain dysfunction, may be cognitively unable to judge their sleep quality. The aim of the present study is to examine, in AUD and KS patients, whether the absence of sleep complaint is associated with altered brain structure and impaired cognitive abilities within specific cerebral networks. MethodsAn assessment of subjective sleep quality was conducted in 20 healthy controls, 37 AUD patients, and 17 KS patients. Patients were first pooled together and then classified into 2 groups (no-complaint(AUD+KS) and complaint(AUD+KS)) according to the total Pittsburg Sleep Quality Index score. Cognitive scores, gray matter (GM) volume, and white matter (WM) integrity were compared between these 2 groups, and then in AUD and KS patients separately. ResultsPoor sleep quality was reported by 70% of AUD and 18% of KS patients. Compared to controls, both no-complaint(AUD+KS) and complaint(AUD+KS) presented cortical and subcortical alterations as well as episodic memory deficits, which were more severe in patients without sleep complaint. Only no-complaint(AUD+KS) presented executive deficits. Then, considering the clinical diagnosis, GM volume in frontotemporal regions, WM integrity, and executive functions were affected to the same extent in AUD and KS patients without sleep complaint. ConclusionsOur results confirm the high prevalence of sleep complaint in AUD patients and the rare complaint in KS patients. In AUD and KS patients, the absence of sleep complaint may not indicate good sleep quality but rather reflect executive deficits and frontothalamic damage. Alcohol-related cognitive deficits may indeed alter the ability to self-evaluate sleep quality, suggesting that the use of sleep questionnaire should be considered with caution in patients with executive deficits.