By Mo Costandi of Nature magazine

New Orleans, Louisiana—A disturbed night's sleep might signal a future diagnosis of Alzheimer’s disease, according to findings presented this week at the annual meeting of the Society for Neuroscience in New Orleans, Louisiana.

Patients with Alzheimer’s often complain of changes in their sleep patterns during the early stages of the disease. In healthy people, for example, daytime naps usually last around 20 minutes, but they can be to 3 hours long in patients with Alzheimer’s disease.

Roxanne Sterniczuk, a neurophysiologist at Dalhousie University in Halifax, Canada, and her colleagues wanted to determine how early these changes occur and if they could predict a person’s future risk of developing the disease.

Sterniczuk and her colleagues analyzed data from around 14,600 healthy people, collected as part of the Survey of Health, Ageing and Retirement in Europe (SHARE), a long-term observational study of people aged 50 and over from 12 European countries. They looked at various measures of sleep quality, and used them to produce a ‘sleep disturbance index’.

The researchers found that participants who reported sleeping restlessly, feeling tired during the day and taking sleep medication were more likely to be diagnosed with Alzheimer’s within the next 2 years, and that the greater the extent of these problems, the more severe were the symptoms of the subsequent disease.

“Increased daytime sleepiness was the biggest predictor,” says Sterniczuk. “It would appear that subtle changes in the sleep–wake cycle are taking place before any disease pathology.”

Early marker
Alzheimer’s disease is characterized by two hallmarks — the deposition of insoluble plaques made up of amyloid- ß protein, which accumulate in the spaces around nerve cells, and protein aggregates called neurofibrillary tangles that are deposited inside cells.

Sleep disturbances may be an early marker for the brain changes that occur as the disease develops, or they may contribute to progression of the disease, says David Holtzman, a neurologist at Washington University School of Medicine in St Louis, Missouri, who studies Alzheimer’s disease. “Either that pathology is beginning to occur during ageing, or sleep problems lead to accelerated Alzheimer’s pathology and disease,” he adds.

Last month, Holtzman and his colleagues reported that in a mouse model of Alzheimer’s the sleep–wake cycle breaks down following the formation of amyloid-ß plaques, and that eliminating the plaques caused the cycle to return to normal, suggesting that plaque formation causes the sleep disturbances. But he adds that distinguishing between the two possibilities in humans will require long-term studies to assess how biological markers associated with Alzheimer’s disease change through life.

Sterniczuk is now investigating whether the changes in sleep patterns are related to alterations in gene activity in the suprachiasmatic nucleus, a region of the brain that controls the circadian rhythm and regulates the sleep–wake cycle.

She emphasizes how important it is to find ways to accurately diagnose the condition and identify people at risk of developing it. “We have an ageing population on our hands, and there may be an Alzheimer’s pandemic in the next 10–15 years as the baby boomers reach the typical age of diagnosis,” she says.

This article is reproduced with permission from the magazine Nature. The article was first published on October 18, 2012.

8 Comments

1. 1. jobjobx 03:36 PM 10/18/12

   This article would be much more interesting if it said HOW MUCH more likely, not just "more likely."

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2. 2. Martha Stettinius 09:10 PM 10/18/12

   Sleep apnea--not mentioned here--is hugely under-diagnosed, and a significant risk factor for Alzheimer's disease. A study led by the University of California, San Francisco, shows that elderly women who have sleep apnea are about twice as likely to develop dementia than those without the condition. Other researchers find that people whose nightly sleep is short or disturbed have higher levels of beta amyloid, the protein that causes plaques between brain cells. According to a study at the Washington University School of Medicine in St. Louis, in younger people, or older people who sleep well, excess beta amyloid drains out of their brains during sleep into their spinal fluid. In 2010, researchers in Milan, Italy, found that CPAP therapy can restore brain tissue in people with sleep apnea. The National Sleep Foundation estimates that more than 18 million American adults have sleep apnea. According to the
   American Sleep Apnea Association, sleep apnea is as common as Type II diabetes, but “because of the lack of awareness by the public and health care professionals, the vast majority of sleep apnea
   patients remain undiagnosed and therefore untreated.” If you snore, wake up tired, experience morning headaches, or feel exhausted all day despite sleeping a decent number of hours at night, ask your doctor for a referral to a sleep clinic. Your brain may be at risk.
   --Martha Stettinius, author, "Inside the Dementia Epidemic: A Daughter's Memoir" www.insidedementia.com
   

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3. 3. Wayne Williamson 04:15 PM 10/19/12

   poster #3 should probably be removed for spam.
   
   This "herbal" treatment is NOT approved by the FDA and is currently under investigation for making false, not scientifically verified claims. Don't be fooled by their baseless claims and shameless attempts to make make a buck on the backs of countless victims of this terrible disease.
   Link: http://www.fda.gov/ICECI/EnforcementActions/WarningLetters/2004/ucm146723.htm

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4. 4. Eceren 08:49 AM 10/20/12

   "old people who has insomnia(they melotonin levels are low) can cure with melatonin treatment" if we use this knowledge,could progression of alzheimer is delayed?

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5. 5. MarkWilliams 07:58 PM 10/21/12

   How could they study the links between sleep disturbance and dementia and not mention sleep apnea?!?! Seriously, they interviewed fourteen thousand people and it never occured to them to ask if anybody had sleep apnea?

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6. 6. Rich32 05:12 PM 10/24/12

   Another infrequently mentioned cause of dementia is adult onset hydrocephalus. I know because I was diagnosed with it in 2001 and had a shunt installed in 2002 which cured my problem although I may be having that or other problems now, pending diagnosis. Hydrocephalus is more recognized now than in the past, but anyone with problems should insure that they have a scan to eliminate or confirm it before the brain is shrunken beyond repair. If in doubt, contact the Hdrocephalus Association for help in finding a knowledgeable neurologist in your area.

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7. 7. jimfromcanada 12:20 AM 10/25/12

   How do you remove amyloid plaques?
   

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8. 8. bucketofsquid in reply to jimfromcanada 06:16 PM 11/1/12

   In a healthy person amyloid-B plaques are removed while sleeping. In unhealthy people it builds up and can only be removed via medication or by having some amyloid-B extracted from your brain and injected elsewhere in your body to trigger an immuno response. The extraction does not sound fun.

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