Binge drinking twice a month more than doubles cognitive function decline (147%), and memory decline could increase more than fivefold (149%), according to Lang's study.
For those patients, doctors can then look for other potential causes of the memory decline, which may have another prognosis or be treated differentially than Alzheimer's, he said.
Once their effectiveness has run its course, memory loss and cognitive decline progress unimpeded, and sometimes even accelerate.
And there's no way to halt or reverse the decline of memory and other cognitive abilities once Alzheimer's has been diagnosed.
The experts aren't sure yet, but people with migraines don't seem to be at greater risk of memory loss or mental decline as they age.
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Likewise, if DRAM ever loses out to magnetic memory, cache chips will decline alongside it.
Nonsmokers were 1.84-fold more likely to be in the "no memory loss" category compared with those with minor decline.
Especially confusing, says Gazzaley, is that key brain functions, like short-term memory, processing speed, and the capacity to multi-task, decline steadily as we age.
It may be that loneliness may affect systems in the brain dealing with cognition and memory, making lonely people more vulnerable to effects of age-related decline in neural pathways, he suggested.
"Take away the gains in the memory business, and what you would have had is a 1% percent decline for the industry overall, " Matas says.
Bernstein puts the compound annual decline at 32% between 2007 and 2011, noting the eerie similarity with the price of computer memory, which has fallen at an annual compound rate of 33.4% since 1974.
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