NEW YORK, Nov. 6 (UPI) -- Experiencing excessive daytime sleepiness as an older adult can spell dire consequences that ultimately may lead to full-blown dementia, according to a new study funded by the National Institute on Aging. The study was published online Wednesday in Neurology, the medical journal of the American Academy of Neurology. Advertisement Sleep dysfunction raises the risk of motoric cognitive risk syndrome, a type of predementia that can progress to dementia, researchers found.