Sleeplessness Tied to Early Alzheimer's, Study Says

TUESDAY, Feb. 14 (HealthDay News) -- Poor-quality sleep may have worse effects than simple fatigue: A preliminary new study suggests it's linked to the buildup of brain plaques seen in people with Alzheimer's disease.

Researchers at Washington University School of Medicine in St. Louis monitored the sleep patterns of 100 mentally healthy people between the ages of 45 and 80 -- half of whom had a family history of Alzheimer's disease -- and found that those who awakened more than five times an hour were more likely to have amyloid plaque accumulations than those with fewer sleep disturbances.

Amyloid protein plaques are a trait of Alzheimer's, a condition affecting at least 5.4 million Americans that robs patients of memory and reasoning skills. These characteristics, detectable with brain scans and spinal fluid tests, can appear years before Alzheimer's symptoms begin.

"We were initially looking at duration of sleep, but it seems the quality of sleep is more important to this association," said study author Dr. Yo-El Ju, an assistant professor of neurology. "We don't know if early Alzheimer's is causing poor sleep, or vice-versa.

"It's possible that there's some change in brain activity going on during sleep that allows soluble amyloid to decrease overnight," Ju added, "but we need to study this much more closely."

Preliminary results from the study were released Feb. 14 in advance of their presentation at the American Academy of Neurology's annual meeting in April in New Orleans.

For two weeks, study participants wore a device on their wrists that determined whether they were awake or asleep depending on body movements. They also filled out sleep diaries and questionnaires, and underwent brain imaging and spinal fluid tests.

Testing showed that 25 percent had preclinical indicators for Alzheimer's disease, and researchers found that those who slept "less efficiently" were more likely to have the indicators for early-stage Alzheimer's than those with uninterrupted sleep. While the average time spent in bed was about eight hours, the average sleep time was 6.5 hours because of brief awakenings in the night. Those who spent less than 85 percent of their time in bed actually sleeping were more likely to have Alzheimer's traits, or biomarkers.

Because the study, which should be completed in several months, is still under way, Ju said it isn't yet known whether participants with a family history of Alzheimer's are more likely to suffer from disturbed sleep or show biological indicators of the condition.

"Results are very promising, but it's very important to follow the people who don't have any type of early Alzheimer's because that's the only way we'll know what comes first," disturbed sleep or Alzheimer's biomarkers, she said. Because while the study uncovered an association between poor sleep and plaque formation, it did not prove a cause-and-effect relationship.

Dr. Daniel Potts, a partner at Alabama Neurology and Sleep Medicine in Tuscaloosa, said he suspects that chronic poor-quality sleep will eventually be proven to contribute to amyloid plaque formation.

If that cause-effect relationship is established, scientists may be able to "tailor an intervention" to improve sleep for those affected, Potts said.

"That's my hunch. It makes sense to me," said Potts, also a spokesperson for the American Academy of Neurology. "The best possible thing we could get out of this would be that we could do something about it. But there's not enough data to step out and say [for certain] at this point."

Research presented at medical meetings should be considered preliminary until published in a peer-reviewed medical journal.

More information

The Alzheimer's Association has more information about amyloid protein plaques.

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Blurry line in diagnosing early Alzheimer's: study

NEW YORK (Reuters Health) - The revised definition of a brain condition called mild cognitive impairment means that many people now considered to have mild or early Alzheimer's disease could easily be given that diagnosis instead, suggests a new study.

Mild cognitive impairment is already seen by doctors as the first hint of a future Alzheimer's diagnosis in many cases. And the new definition will blur those lines even more, the new report concludes -- begging the question of whether it should be its own diagnosis at all.

"There's been a lot of controversy... about the whole classification called mild cognitive impairment," said Dr. Peter Whitehouse, a geriatric neurologist at the Case Western Reserve University School of Medicine in Cleveland, who wasn't involved in the study.

"The major issue since the beginning (has been) defining its boundaries. Inventing a label like this," he told Reuters Health, "creates confusion."

Mild cognitive impairment was originally diagnosed in people with memory problems but no other difficulties in thinking and reasoning abilities or in completing daily activities.

But that definition has morphed over time to include more people, and in recent recommendations made for the National Institute on Aging and the Alzheimer's Association, now covers people with some trouble doing household chores and hobbies, according to Dr. John Morris, from Washington University in St. Louis.

Those functional problems have traditionally been part of an early Alzheimer's diagnosis.

Morris, the new study's sole author, said he thinks there's so much confusion because most cases of mild cognitive impairment really are the first signs of Alzheimer's.

Other cognitive problems could be due to a stroke, certain medications or thyroid problems, he said -- things that doctors could find explanations for if they kept looking and don't require a separate diagnosis or label, he said.

Morris examined data on more than 17,000 people evaluated for Alzheimer's disease at 33 different centers between 2005 and 2011, including about 6,000 who were originally diagnosed with full-on Alzheimer's or mild dementia related to Alzheimer's.

Those people were 75 years old when they were tested, on average, according to the report published in Archives of Neurology.

Morris determined that based on the new definition of mild cognitive impairment -- including the criterion that someone can have some difficulty with everyday activities -- almost every person with "very mild" Alzheimer's disease dementia could be diagnosed with mild cognitive impairment instead.

That was also the case for more than 90 percent of people with "mild" Alzheimer's disease.

The overlap could lead to a lot of subjective decisions on the part of doctors, according to Morris, when it comes to who has early Alzheimer's and who has mild cognitive impairment -- or to avoiding an Alzheimer's diagnosis because it's seen as "stigmatizing," Morris told Reuters Health.

But that's not usually a good thing for patients and their families, he added.

"If we think the cause of the cognitive impairment is underlying Alzheimer's, by providing the diagnosis to the best of our accuracy, it does allow the patient and the family to start dealing with the reality of the disease at a stage when the patient still has plenty of cognitive ability to participate in those decisions," Morris said.

According to the Alzheimer's Association, 5.4 million people in the United States have the disease, including one in eight aged 65 and older.

Creighton Phelps, head of the Alzheimer's Disease Centers Program at the National Institute on Aging, said that to a certain extent, the line between mild cognitive impairment and early Alzheimer's is indeed "fuzzy" and depends on a doctor's individual judgment. But he added that many researchers still think there's a point in between normal thinking and functioning and Alzheimer's dementia that deserves its own category.

"What other experts say is, you should not be calling it dementia too early, until you're absolutely sure about it," Phelps told Reuters Health.

"In (mild cognitive impairment), you pick up some very early changes. They don't have to quit their job, it's not interfering with their life, but it's measureable," he said. "It's not enough to move them into the dementia category."

Whitehouse said that all of the divisions between normal and mild cognitive impairment and Alzheimer's miss the most important point: that everyone, as they age, should be taking steps to maintain their brain health. That includes keeping your mind and body active, eating a healthy, Mediterranean-style diet and keeping engaged socially, he added.

SOURCE: http://bit.ly/xHTMf8 Archives of Neurology, online February 6, 2012.

(This story was corrected to change the journal name in paragraph 11, the source line and study link)

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