People in the earliest clinical stages of Alzheimer’s disease, behavioral variant frontotemporal dementia and dementia with Lewy bodies show distinct patterns of sleep disturbance, according to a prospective cohort study published in Alzheimer’s Research & Therapy. The study, which is being shared early as a peer-reviewed, accepted manuscript subject to further edits, found that patients with dementia with Lewy bodies carried the highest overall burden of sleep disturbances relative to the other groups examined.
The research team recruited 111 early-stage patients from Kuopio and Oulu University Hospitals in Finland: 60 patients with Alzheimer’s disease with a mean age of 64.3 years, 35 patients with behavioral variant frontotemporal dementia with a mean age of 62.4 years, and 16 patients with dementia with Lewy bodies with a mean age of 71.1 years. A comparison group of 63 cognitively healthy controls, with a mean age of 59.0 years, was recruited alongside the patients.
Early-stage disease was defined using the Clinical Dementia Rating Scale, with a global score of 0 to 1. This means the participants were at or near the very beginning of symptomatic disease, a window in which reliable prevalence data on sleep disorders and symptoms have been limited, as the authors note in the study’s background.
Sleep was assessed with the Basic Nordic Sleep Questionnaire, a structured instrument that characterizes prior sleep habits, sleep disorders and the use of sleep-related hypnotic drugs. The questionnaire-based approach captures self-reported sleep behavior rather than objectively measured sleep, which is a relevant limitation when interpreting the findings.
Several differences emerged when the disease groups were compared with one another. When behavioral variant frontotemporal dementia was compared with Alzheimer’s disease, patients with frontotemporal dementia reported more apneas during sleep: 18 percent versus 4 percent, a difference the authors report as statistically significant (p = 0.024, OR = 0.17, 95% CI 0.03–0.92).
Comparisons with the healthy controls produced some counterintuitive results. Patients with behavioral variant frontotemporal dementia exhibited fewer nighttime awakenings than controls, at 44 percent versus 71 percent (p = 0.003, OR = 0.22, 95% CI 0.08–0.59), and reported roughly one hour more sleep per day, 8.46 hours versus 7.59 hours (general linear model, p = 0.020, B = -0.70). Patients with Alzheimer’s disease similarly reported more daily sleep than controls, 8.40 hours versus 7.59 hours (general linear model, p = 0.001, B = -0.78).
Total sleep duration did not differ significantly between the three disease groups, indicating that while the profiles of specific sleep problems varied, the overall quantity of sleep reported was similar across diagnostic categories at this early stage.
The authors conclude that sleep disturbance profiles differed across the disease groups at an early stage, but that differences were modest when the patient groups were compared with cognitively healthy controls. They suggest the findings indicate that sleep disturbances may already be present in the early disease stage. Because the study is a prospective cohort of 174 participants in total from two Finnish university hospitals, and because the DLB subgroup comprised only 16 patients, the reported prevalence estimates for individual diagnostic groups should be interpreted with appropriate caution until the final version of record and further studies are available.
Subject of Research: Sleep disturbance profiles in early-stage Alzheimer's disease, behavioral variant frontotemporal dementia and dementia with Lewy bodies
Article Title: Different profiles of sleep disturbances in early-stage neurocognitive diseases: a prospective cohort study
Article References: Kinnunen, M., Krüger, J., Vitikka, E., Haapasalo, A., Kurl, S., Borroni, B., Säisänen, L., Katisko, K., & Solje, E. (2026). Different profiles of sleep disturbances in early-stage neurocognitive diseases: a prospective cohort study. Alzheimer's Research & Therapy. https://doi.org/10.1186/s13195-026-02246-7
Image Credits: AI Generated
DOI: 10.1186/s13195-026-02246-7
Keywords: sleep disturbances, Alzheimer's disease, frontotemporal dementia, dementia with Lewy bodies, early-stage neurocognitive disease, prospective cohort study, Basic Nordic Sleep Questionnaire, Clinical Dementia Rating, nighttime awakenings, sleep apnea, sleep duration, hypnotic drug use
News Source: Cassandra Pierce. (October 29, 2026). Sleep disturbance profiles differ across early-stage Alzheimer’s, frontotemporal dementia and Lewy body disease. Scienmag.
