Obstructive sleep apnea syndrome and Alzheimer’s disease

Obstructive sleep apnea syndrome (OSA) is a risk factor for cardiovascular disease, obesity and other conditions. Recent evidence has emerged regarding the impact of OSA on cognitive function and the severity of cognitive impairment, including in Alzheimer’s disease (AD).

Objective: to assess the prevalence of OSA in patients with asthma and its impact on the severity of cognitive impairment.

Material and methods. A study was conducted involving 47 participants: 25 patients with the amnestic variant of AD (8 men and 17 women; mean age – 71.0 [65.0; 74.0] years) and 22 cognitively intact volunteers (6 men and 16 women; mean age – 60.0 [57.25; 62.5] years). All participants underwent a review of their complaints and anamnesis, neuropsychological testing using the Montreal Cognitive Assessment (MoCA) and the Addenbrooke’s Cognitive Examination-III (ACE-III), a subjective sleep assessment, and polysomnography.

Results. In patients with AD, OSA and excessive daytime sleepiness are significantly more common than in the control group (p=0.027). A statistically significant reduction in total scores on the MoCA and ACE-III scales was observed in the presence of OSA, with a more pronounced reduction in severe cases. A higher apnea-hypopnea index (AHI) is frequently observed in individuals with excessive daytime sleepiness (p=0.033) and in the group of patients complaining of various manifestations of sleep disturbance (p=0.020), in particular early awakening (p=0.013). With an AHI of 15 episodes per hour, excessive daytime sleepiness was more frequently detected and a lower cognitive status was noted based on the total scores of the MoCA and ACE-III scales. Correlation analysis revealed that an increase in AHI is associated with a deterioration in cognitive status, a reduction in total sleep time and sleep efficiency, the duration of stage 3 sleep (deep sleep), and an increase in sleep latency, wake time after sleep onset, the duration of stages 1 and 2 sleep (light sleep), the number and index of microarousals, and the desaturation index.

Conclusion. OSA was diagnosed in 76% of patients with AD, whereas in the control group it was found in only 36.3% of individuals. As the severity of OSA increases, a deterioration in cognitive function is observed.

1. Darien IL. American Academy of Sleep Medicine. International classification of sleep disorders. 3rd ed. 2014.

2. Bahr K, Geisler V, Huppertz T, et al. Intensity of Respiratory Cortical Arousals Is a Distinct Pathophysiologic Feature and Is Associated with Disease Severity in Obstructive Sleep Apnea Patients. Brain Sci. 2021 Feb;11(3):282. doi: 10.3390/brainsci11030282

3. Jang JW, Ju HM, Jeon HM, et al. Obstructive Sleep Apnea: Pathophysiology and Treatment. J Oral Med Pain. 2024;49:71-8. doi: 10.14476/jomp.2024.49.4.71

4. Litvin AYu, Chazova IE, Elfimova EM, et al. Eurasian Association of Cardiology (EAC)/ Russian society of somnologists (RSS) guidelines for the diagnosis and treatment of obstructive sleep apnea in patients with cardiovascular diseases (2024). Eurasian Heart Journal. 2024;(3):6-27 (In Russ.). doi: 10.38109/2225-1685-2024-3-6-27

5. Slater G, Steier J. Excessive daytime sleepiness in sleep disorders. J Thorac Dis. 2012 Dec;4(6):608-16. doi: 10.3978/j.issn.2072-1439.2012.10.07

6. Lal C, Weaver TE, Bae CJ, Strohl KP. Excessive Daytime Sleepiness in Obstructive Sleep Apnea. Mechanisms and Clinical Management. Ann Am Thorac Soc. 2021 May;18(5):757-68. doi: 10.1513/AnnalsATS.202006-696FR

7. Senaratna CV, Perret JL, Lodge CJ, et al. Prevalence of obstructive sleep apnea in the general population: A systematic review. Sleep Med Rev. 2017 Aug;34:70-81. doi: 10.1016/j.smrv.2016.07.002

8. Braley TJ, Dunietz GL, Chervin RD, et al. Recognition and Diagnosis of Obstructive Sleep Apnea in Older Americans. J Am Geriatr Soc. 2018 Jul;66(7):1296-302. doi: 10.1111/jgs.15372

9. Mediano O, Gonzalez Mangado N, Montserrat JM, et al. International Consensus Document on Obstructive Sleep Apnea. Documento internacional de consenso sobre apnea obstructiva del sueno. Arch Bronconeumol. 2022 Jan;58(1):52-68. doi: 10.1016/j.arbres.2021.03.017

10. Legault J, Thompson C, Martineau-Dussault ME, et al. Obstructive Sleep Apnea and Cognitive Decline: A Review of Potential Vulnerability and Protective Factors. Brain Sci. 2021 May;11(6):706. doi: 10.3390/brainsci11060706

11. Pan T, Liu S, Ke S, et al. Association of obstructive sleep apnea with cognitive decline and age among non-demented older adults. Neurosci Lett. 2021 Jun;756:135955. doi: 10.1016/j.neulet.2021.135955

12. Shi L, Chen SJ, Ma MY, et al. Sleep disturbances increase the risk of dementia: A systematic review and meta-analysis. Sleep Med Rev. 2018 Aug;40:4-16. doi: 10.1016/j.smrv.2017.06.010

13. Ungvari Z, Fekete M, Lehoczki A, et al. Sleep disorders increase the risk of dementia, Alzheimer's disease, and cognitive decline: a meta-analysis. Geroscience. 2025 Jun;47(3):4899-920. doi: 10.1007/s11357-025-01637-2

14. Marchi NA, Solelhac G, Berger M, et al. Obstructive sleep apnoea and 5-year cognitive decline in the elderly. Eur Respir J. 2023 Apr;61(4):2201621. doi: 10.1183/13993003.01621-2022

15. Bawden FC, Oliveira CA, Caramelli P. Impact of obstructive sleep apnea on cognitive performance. Arq Neuropsiquiatr. 2011 Aug;69(4):585-9. doi: 10.1590/s0004-282x2011000500003

16. Born J, Wilhelm I. System consolidation of memory during sleep. Psychol Res. 2012 Mar;76(2):192-203. doi: 10.1007/s00426-011-0335-6

17. Albert MS, DeKosky ST, Dickson D, et al. The diagnosis of mild cognitive impairment due to Alzheimer's disease: recommendations from the National Institute on Aging-Alzheimer's Association workgroups on diagnostic guidelines for Alzheimer's disease. Alzheimers Dement. 2011 May;7(3):270-9. doi: 10.1016/j.jalz.2011.03.008

18. Troester MM, Quan SF, Berry RB, et al. The AASM Manual for the Scoring of Sleep and Associated Events: Rules, Terminology and Technical Specifications. Version 3. 2023.

19. Xie L, Kang H, Xu Q, et al. Sleep drives metabolite clearance from the adult brain. Science. 2013 Oct;342(6156):373-7. doi: 10.1126/science.1241224

20. Havekes R, Park AJ, Tudor JC, et al. Sleep deprivation causes memory deficits by negatively impacting neuronal connectivity in hippocampal area CA1. Elife. 2016 Aug;5:e13424. doi: 10.7554/eLife.13424

21. Prince TM, Wimmer M, Choi J, et al. Sleep deprivation during a specific 3-hour time window post-training impairs hippocampal synaptic plasticity and memory. Neurobiol Learn Mem. 2014 Mar;109:122-30. doi: 10.1016/j.nlm.2013.11.021

22. Vecsey CG, Baillie GS, Jaganath D, et al. Sleep deprivation impairs cAMP signalling in the hippocampus. Nature. 2009 Oct;461(7267):1122-5. doi: 10.1038/nature08488

23. Tsai CY, Su CL, Huang HT, et al. Mediating role of obstructive sleep apnea in altering slowwave activity and elevating Alzheimer's disease risk: Pilot study from a northern Taiwan cohort. Sleep Health. 2025 Feb;11(1):80-90. doi: 10.1016/j.sleh.2024.08.012

24. Gills JL, Bubu OM. Obstructive Sleep Apnea and Alzheimer's Disease Pathology: Is Sleep Architecture the Missing Key? J Alzheimers Dis. 2024;98(1):69-73. doi: 10.3233/JAD-231385

25. Hassan Mohmmed Ahmed AF, Emam Mohamed Ahmed NMA, Abdulwahid Elsamany AA, et al. The Role of Sleep Disturbances in Alzheimer's Disease Progression: A Systematic Review. Cureus. 2025 Jun 20;17(6):e86450. doi: 10.7759/cureus.86450

26. Oliver C, Li H, Biswas B, et al. A systematic review on adherence to continuous positive airway pressure (CPAP) treatment for obstructive sleep apnoea (OSA) in individuals with mild cognitive impairment and Alzheimer's disease dementia. Sleep Med Rev. 2024 Feb;73:101869. doi: 10.1016/j.smrv.2023.101869