Alzheimer's Symptoms Triggered by Disturbed Sleep

Sleep deprivation has been associated with increased risk of Alzheimer's disease, according to the results of a new pre-clinical study.

The study, published in the peer-reviewed scientific journal Neurobiology of Aging, examined the effects disturbances in standard sleep cycles had on lab mice.

For eight weeks, researchers deprived the sleep of a group of 6-month old mice -- the aging equivalent of human 40 years old. They did this by exposing the mice to 20 hours of bright light a day, as opposed to the 12 hours of light a control group of the same type of mice received.

Past studies have concluded that bright light tricks the brain into suppressing hormones that would normally help an organism fall asleep. This is why it has been found that even the bright LED screen of a cell phone can keep someone up for far longer than he or she intended.

Past studies have also provided evidence that indicates that sleep deprivation leads to widespread pain, elevated stress levels, and even depression.

In the case of the sleep deprived mice, only four hours of darkness every 24 hours for 8 weeks led to a massive change in their cognitive abilities, compared to the control group.

Memory testing of the two groups revealed that the group with reduced sleep time demonstrated massive impairment in the use and retention or memory. The sleep-deprived mice also exhibited a decreased ability to learn, compared to their well-rested counterparts.

Critics can in part attribute these results to a natural increased difficulty in focusing when tired. However, at the conclusion of the study, an examination of the mice's brains revealed an elevated level of phosphorylated tau protein, which disrupts the ability for brain cells to transmit electrical signals and nutrients to one another. Over time, this disruption would encourage cell degradation and slow synaptic communication in the brain -- essentially encouraging symptoms of dementia. Such a turn of events is not uncommon in contributing to the eventual development of Alzheimer's disease in humans.

The researcher concluded that chronic sleep disturbance is a dangerous environmental risk factor for Alzheimer's disease, and should be treated as soon as possible to reduce the risk of dementia.

The study was published in Neurobiology of Aging on February 18 (recently corrected by publishing party).