Prevalence and clinical implications of Rapid eye movement sleep behavior disorder in Alzheimer's disease and Lewy body dementia.

Rapid eye movement sleep behavior disorder (RBD) is increasingly recognized as a significant clinical feature in neurodegenerative diseases like Alzheimer's disease (AD) and Lewy body dementia (LBD). This study investigates the prevalence and clinical implications of RBD among individuals diagnosed with AD and LBD, emphasizing its relationship with cognitive decline. A retrospective observational study analyzed data from 5,481 participants across four diagnostic groups: AD + LBD, AD, LBD, and cognitively normal controls. Multinomial logistic regression and multivariable analyses were performed to assess RBD associations with demographic, clinical, and neuropsychiatric factors. Limitations include reliance on self-reported questionnaires to identify RBD, which may lead to underdiagnosis and skewed prevalence estimates. RBD prevalence was significantly higher in the AD + LBD (37.40%) and LBD (69.30%) groups compared to AD (3.61%) and cognitively normal controls (2.31%). The odds ratio (OR) for RBD in the AD + LBD group was 12.39 compared to controls (p < 0.001). Other significant associations included male gender and higher neuropsychiatric symptom severity, while age and education demonstrated complex relationships with RBD prevalence. This study highlights RBD as a critical factor in neurodegenerative disease assessment and an early marker for identifying at-risk individuals. Recognizing RBD's role in cognitive decline emphasizes the need for integrated clinical approaches that incorporate sleep assessments in dementia management and inform strategies for improving patient quality of life.