Sleep disorders as 'predictive markers' in Alzheimer's disease and Lewy body dementia

Abstract

Sleep disturbances are common and clinically significant non-cognitive symptoms in Alzheimer's disease and Lewy body dementia. Although the two conditions share partially overlapping pathology, they exhibit distinct sleep-related profiles that can support differential diagnosis and early medical intervention. Comparison of sleep disorders in Alzheimer’s disease and Lewy body dementia, focusing on prevalence, clinical and neurobiological features, and treatment response for diagnosis and treatment. Comparison of sleep disorders in Alzheimer’s disease and Lewy body dementia, focusing on prevalence, clinical and neurobiological features, and treatment response for diagnosis and treatment. This study synthesized data from ten high-quality studies selected from PubMed, PsycINFO, Google Scholar, and NCBI databases. The included studies consisted of multicenter analyses, systematic reviews, and meta-analyses that assessed sleep disturbances using validated behavioral and actigraphy-based methods in clinical and neuroimaging cohorts. REM sleep behavior disorder and excessive daytime sleepiness are more common in Lewy body dementia (44–72%) than in Alzheimer’s disease (15–35%), often preceding cognitive symptoms and associated with brainstem and occipital cortex dysfunction. In Alzheimer’s disease, patients predominantly exhibit insomnia, fragmented sleep, and reduced slow-wave sleep, linked to hippocampal atrophy. Non-pharmacological treatments, such as light therapy and behavioral interventions, have shown greater effectiveness in Alzheimer’s disease, while melatonin and cholinesterase inhibitors have provided benefits in Lewy body dementia. Sleep disorders differ significantly between Alzheimer’s disease and Lewy body dementia in terms of type, severity, and treatment response. Recognizing these specific clinical patterns may facilitate early differential diagnosis and guide personalized therapeutic interventions.