There appears to be a strong association of being an E4 carrier and developing sleep apnea. Plus, if you are a carrier, the apnea is worse, even though you might not have the stereotypical signs of being at risk for sleep apnea (obese, large neck size, male). http://www.ncbi.nlm.nih.gov/pubmed/12127169http://www.alzforum.org/news/research-n ... entia-risk
In E4 carriers, unlike non-carriers, the sleep apnea was associated with lower cognitive tests.http://www.researchgate.net/publication ... 4_Carriers
I could not find where sleep apnea had been previously discussed. From my personal experience, having been diagnosed with "critical severe sleep apnea" a few years ago, I've always been perplexed as to why I had such a diagnosis. I was essentially without complaints, and was diagnosed as my husband had sleep apnea, and thought I should get a baseline sleep study.
By 2015, we should have the results of a NYU study as to what came first, the sleep apnea or the Alzheimer's. Researchers are questioning that early brain injury due to Alzheimer's might create sleep apnea. On the other hand, we know that sleep apnea shrinks the hippocampus, so would not this contribute to the memory decline?