A study published in Alzheimer's & Dementia has revealed that the integrity of the locus coeruleus, a brainstem structure crucial for regulating the sleep-wake cycle, correlates with improved deep sleep quality in both healthy individuals and those at various stages of Alzheimer's disease. The study highlights sex differences and the role of vascular health factors.
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Led by Neus Falgàs, a researcher in the IDIBAPS Alzheimer's Disease and Other Cognitive Disorders Group, alongside Raquel Sánchez-Valle, the medical director at Clínic and head of the research group, the study offers new insights into the connection between Alzheimer's disease and sleep issues.
Alzheimer's disease is a progressive neurodegenerative condition that affects memory and cognitive functions, often leading to significant sleep disturbances, particularly a reduction in slow-wave sleep, which is crucial for memory and overall brain health. Previous preclinical studies had suggested a link between the locus coeruleus and deep sleep regulation, primarily through noradrenaline production.
Earlier research from Clínic-IDIBAPS indicated that the locus coeruleus's condition is related to the severity of neuropsychiatric symptoms, including sleep problems. This latest study advances the understanding by focusing on specific deep sleep metrics.
The research team conducted polysomnography to analyze nighttime brain activity among 58 participants, spanning healthy individuals, those with mild cognitive impairment, and patients with Alzheimer's dementia. They correlated these findings with neuroimaging markers and biomarkers to assess sleep quality, locus coeruleus status, and health indicators related to vascular and glymphatic systems.
The results demonstrated that individuals with a well-preserved locus coeruleus showed significantly higher slow-wave sleep activity, indicating better deep sleep quality. Neus Falgàs noted that this correlation was particularly pronounced in women, suggesting potential biological or hormonal influences.
Furthermore, increased presence of perivascular spaces in the basal ganglia, a marker of cerebral vascular health, related to lower slow-wave activity, indicating that both the state of sleep-regulating structures and cerebral blood vessel health may influence deep sleep quality.
The research team emphasized that these findings underscore the importance of deep sleep for brain health and suggest that the interplay between the locus coeruleus, vascular factors, and sex differences might affect the progression of Alzheimer's disease.
Longitudinal studies are warranted to evaluate whether maintaining locus coeruleus function or enhancing vascular health can help preserve sleep quality and potentially influence the disease trajectory.
This work was a collaborative effort involving multiple teams from the Alzheimer's and Other Cognitive Disorders Unit, the Functional Testing Section, and the Cerebral Vascular Pathology Unit of the Neurology Service, supported by IDIBAPS's Neuroimaging Platform, along with external collaborators such as the Barcelona Beta Brain Research Center and Mayo Clinic Florida.
The study is referenced as: Falgàs N, et al. Relationship between locus coeruleus and slow-wave sleep in aging and Alzheimer's disease. Alzheimers Dement. 2026 Feb;22(2):e71183. doi: 10.1002/alz.71183.