Subtle alterations in sleep patterns, specifically an increase in micro awakenings, could signal a heightened risk of developing dementia, according to a European study. These brief moments of partial arousal during sleep, typically lasting only a few seconds, are a normal part of a healthy sleep cycle. However, researchers are suggesting that a higher frequency of these micro awakenings may serve as an early indicator of increased vulnerability to cognitive decline.
In a study that monitored 500 adults over a period of up to seven years, scientists observed a correlation between more frequent micro awakenings in middle-aged adults and the presence of genetic markers associated with a higher risk of Alzheimer's disease. One such marker is the APOE4 gene, which has been linked to a 60 percent greater likelihood of an Alzheimer's diagnosis by age 85.
"These micro awakenings are therefore not insignificant," stated Dr. Puneet Talwar, a sleep researcher at the University of Liege, Belgium, and a co-author of the study. "Certain profiles could promote the accumulation of proteins involved in Alzheimer's disease and be associated with increased vulnerability."
Approximately seven million Americans are currently living with Alzheimer's, a number projected to nearly double in the next 24 years. Previous research has indicated that sleep disturbances, poor sleep quality, and daytime sleepiness may elevate the risk of Alzheimer's, potentially by contributing to the buildup of harmful proteins in the brain. The exact mechanism by which genetic markers might influence sleep remains unclear.
The research, published in the journal Sleep, offers a potential method for identifying Alzheimer's risk years before symptoms manifest, as the condition is typically diagnosed in individuals aged 65 and older.
The study involved 453 younger adults with an average age of 22 and 87 middle-aged adults with an average age of 59. Younger participants experienced approximately 250 micro awakenings per night, while older participants averaged about 180 per night. Younger adults slept for roughly seven hours and 30 minutes, while middle-aged adults slept for about six hours and 30 minutes.
Analysis of the data indicated that individuals experiencing a greater number of micro awakenings were more likely to possess genes associated with an increased risk of Alzheimer's. The researchers also utilized brain scans to examine the coeruleus locus, a region in the brainstem responsible for regulating the sleep-wake cycle. They found that sleep quality, including the ability to fall asleep and sleep depth, is dependent on the proper functioning of this area. The coeruleus locus is also crucial for rapid-eye movement (REM) sleep, a phase vital for dreaming and memory consolidation, and has been identified in prior research as one of the earliest sites where abnormal protein deposits appear.
"Sleep could become an accessible marker for the early identification of vulnerable individuals," said Gilles Vandewalle, a sleep researcher and co-author of the study. Lucie Leroux, head of French-speaking activities at the Stop Alzheimer’s Foundation, which funded the research, added, "This research shows that sleep is not only an indicator of health, but also a potential lever for intervention."