Alzheimer's-sleep connection

Researchers have made an interesting discovery about a marker for Alzheimer’s: it mirrors sleep patterns.

The pattern is strongest in healthy young people and reinforces a relationship between increased Alzheimer’s risk and inadequate sleep that had been discovered previously in animal models. This could be related to the brain’s comparative inactivity while sleeping. At night, the marker, amyloid beta, clears out through the spinal fluid.

Researchers from Washington University School of Medicine in St. Louis report that the normal highs and lows of amyloid beta that surround the brain and spinal cord begin to flatten in older adults whose sleep is shorter and often disrupted. When adults develop brain plaques linked to Alzheimer’s the rise and fall is mitigated and the amyloid beta levels become constant.

“In healthy people, levels of amyloid beta drop to their lowest point about six hours after sleep, and return to their highest point six hours after maximum wakefulness,” said Randall Bateman, MD, associate professor of neurology. “We looked at many different behaviors, and the transitions between sleep and wakefulness were the only phenomena that strongly correlated with the rise and fall of amyloid beta in the spinal fluid.”

Stephen Duntley, MD, professor of neurology and director of the center continued, “We’ve known for some time that significant sleep deprivation has negative effects on cognitive function comparable to that of alcohol intoxication, but it’s recently become apparent that prolonged sleep disruption and deprivation can actually play an important role in pathological processes that underlie diseases. This connection to Alzheimer’s disease isn’t confirmed yet in humans, but it could be very important.”

Older adults sleep for shorter periods often without achieve deep slumber. The risk of Alzheimer’s also increases with age; there could be a relationship.

“It’s still speculation, but here are tantalizing hints that better sleep may be helpful in reducing Alzheimer’s disease risk,” said Duntley.

Source: Archives of Neurology, MedicalNewsToday