Can untreated sleep apnea mimic symptoms of dementia? Yes, it often does by causing memory lapses, confusion, trouble focusing, and foggy thinking that look a lot like early dementia signs.[1][3] People with untreated sleep apnea stop breathing repeatedly at night, which cuts oxygen to the brain and disrupts deep sleep.[3] This leads to daytime problems such as forgetting things, struggling to pay attention, and feeling mentally slow, much like mild cognitive impairment seen in dementia.[1][2]
Over time, these effects can get worse. Studies show that low oxygen levels shrink brain areas key for memory and cause changes in blood vessels that harm brain cells.[1][3] Without good sleep, the brain cannot clear out waste proteins linked to Alzheimer’s disease, letting them build up.[3] Brain scans reveal less dense brain matter and disrupted networks for thinking and emotions in those with sleep apnea.[1][2] Women may face even more severe impacts on brain tissue and cognition.[2]
Common signs overlap with dementia. You might nod off during the day despite sleeping enough, snap at others for no reason, or have mood swings.[1][3] Morning headaches, trouble concentrating, and feeling unrested add to the mix.[3] Research from groups like the American Academy of Sleep Medicine finds lower scores on memory and attention tests in untreated cases.[1]
Treating sleep apnea can ease these issues. Tools like CPAP machines improve oxygen flow and sleep quality, often clearing up brain fog and protecting against decline.[1][3] Simple habits such as exercise, better diet, and stress relief help too.[1]
Sources
https://enticare.com/2025/12/19/understanding-sleep-apnea-brain-fog-impact-and-solutions-for-clarity/
https://pmc.ncbi.nlm.nih.gov/articles/PMC12730621/
https://www.nebraskamed.com/health/conditions-and-services/neurological-care/preventing-alzheimers-disease-and-dementia-by
https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/alz70861_108358?af=R
https://pmc.ncbi.nlm.nih.gov/articles/PMC12724476/
https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2843180
https://journals.sagepub.com/doi/abs/10.1177/08919887251403581
