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The Effects of Sleep Apnea on Alzheimer’s Disease

posted Jun 8, 2016, 12:40 AM by Admin SRSAN

Sleep Apnea can be considered a modifiable risk factor for Alzheimer’s disease, according  to a 2015 paper published in the Journal of Neuroscience Research  (Daulatzai 2015).

Alzheimer’s dementia is an irreversible neurodegenerative condition characterized by deposition of amyloid B plaques and neurofibrillary tangles in the brain, with widespread synaptic damage and cognitive dysfunction.

While the mechanisms by which obstructive sleep apnea  contributes to Alzheimer’s disease are not completely understood, they appear to involve  both hypoxic damage and inflammation, promoting lower perfusion and reduced metabolism of the cortex and hippocampus, formation of amyloid B plaques and synaptic dysfunction.  These processes reduce the structural integrity and lead to atrophy of several brain regions, including the medial temporal lobe and hippocampus, which are essential to memory functions.

In another 2015 paper, Gelber et al. show that reduced slow wave sleep (N3 stage) due to sleep fragmentation is associated with more neuronal loss and brain atrophy,  as well as more cognitive decline in men.  Sleep duration with blood oxygenation below 95% was associated with a much higher risk of microinfarcts (almost 4 times greater, when comparing the highest to lowest quartile).    Since both reduced slow wave sleep and blood oxygenation levels below 95% are common in obstructive sleep apnea, this study corroborates Daulatzai’s conclusion that sleep-disordered breathing contributes to cognitive decline in Alzheimer’s dementia.

 

Sources:



Daulatzai, Mak Adam. "Evidence of neurodegeneration in obstructive sleep apnea: Relationship between obstructive sleep apnea and cognitive dysfunction in the elderly." Journal of neuroscience research 93.12 (2015): 1778-1794.

Gelber, Rebecca P., et al. "Associations of brain lesions at autopsy with polysomnography features before death." Neurology 84.3 (2015): 296-303.


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