Could subtle changes during sleep reveal vulnerability to Alzheimer’s disease years before memory problems become noticeable? Researchers at ULiège, supported by the Stop Alzheimer’s Foundation, are investigating whether the sleeping brain may contain early clues.
Scientists from the University of Liège (GIGA Neurosciences) examined sleep patterns in more than 500 healthy people. Among participants in middle age, more frequent nighttime micro awakenings were associated with a higher genetic risk of developing Alzheimer’s disease. That relationship was not detected among younger adults.
The findings, published in the journal Sleep, raise the possibility that sleep measurements could eventually help researchers identify people who may be more vulnerable to Alzheimer’s before symptoms develop.
Looking for Alzheimer’s Clues Before Symptoms
Researchers have spent years investigating connections between disturbed sleep and neurodegenerative diseases. The University of Liège study adds another piece to that research by suggesting that the relationship between sleep and Alzheimer’s risk may begin well before recognizable symptoms emerge.
Because genetics play a partial role in Alzheimer’s disease (Alzheimer’s disease is neither purely hereditary nor entirely independent of genes), the researchers calculated a polygenic risk (i.e., summarizing the combined influence of your genes on your probability of developing a given disease in a single figure) for more than 500 healthy participants.
Most were young adults (aged 18 to 31), while the study also included an older group (aged 50 to 69). Importantly, the polygenic risk measured in the study remained low and cannot determine whether any particular person will eventually develop Alzheimer’s disease.
The researchers then compared these genetic risk estimates with different characteristics of each participant’s sleep.
Tiny Awakenings During the Night
The analysis revealed an association between genetic risk for Alzheimer’s disease and the frequency of nighttime micro awakenings. These are very brief bursts of brain activity that can interrupt the normal sleep cycle without causing someone to become fully awake.
Among the younger participants, researchers found no connection between these micro awakenings and Alzheimer’s genetic risk. A different pattern appeared in the older group. Participants who experienced more frequent micro awakenings also tended to have higher genetic risk, despite being healthy, relatively young and free of Alzheimer’s symptoms.
“These micro-awakenings are therefore not insignificant,” emphasizes Puneet Talwar, a researcher at the GIGA ULiège laboratory, “certain profiles could promote the accumulation of proteins involved in Alzheimer’s disease and be associated with increased vulnerability.”
A Tiny Brain Region Draws Attention
The researchers also examined the locus coeruleus, a tiny area deep within the brainstem that is roughly the size of a grain of rice. It plays an important role in regulating wakefulness, attention, and sleep.
“This region is difficult to observe, but it appears to play a role in the early mechanisms linked to the disease,” explains Gilles Vandewalle, co-director of the GIGA CRC In Vivo Imaging technology platform and Fund for Scientific Research – FNRS Research Director at ULiège.
In 2025, a preliminary study carried out with the 7-Tesla MRI scanner at the ULiège platform allowed the team to examine the locus coeruleus in greater detail. The researchers found that characteristics of sleep quality (speed of falling asleep, depth) were associated with the condition of the brainstem beginning at a young age.
They also found that healthy functioning of the locus coeruleus was related to the quality of REM sleep, a stage of sleep that plays an important role in memory.
The locus coeruleus is especially interesting to Alzheimer’s researchers because it is among the earliest brain regions where abnormal protein deposits can appear. Such deposits may begin accumulating as early as adolescence, although scientists still do not fully understand what these early changes mean.
Could Sleep Become an Early Alzheimer’s Marker?
Taken together, the findings point toward possible new approaches for Alzheimer’s screening and prevention. In the future, analyzing sleep could potentially complement other methods for identifying people who may be vulnerable to the disease before symptoms become apparent.
“Sleep could become an accessible marker for the early identification of vulnerable individuals,” adds Gilles Vandewalle.
Researchers are also interested in whether improving sleep could eventually help prevent or slow disease progression among people with a genetic predisposition to Alzheimer’s.
“This research shows that sleep is not only an indicator of health, but also a potential lever for intervention,” adds Lucie Leroux, head of French-speaking activities at the Stop Alzheimer’s Foundation.
More than 220,000 people in Belgium are affected by Alzheimer’s disease. For now, however, the new findings show statistical associations rather than proof that particular sleep patterns cause or predict the disease. Additional research will be needed to confirm the results, and the findings cannot currently be used to determine whether an individual will develop Alzheimer’s.
Even so, the research provides another glimpse into changes that may occur long before Alzheimer’s becomes clinically visible and underscores the value of basic research aimed at understanding and, eventually, anticipating the disease.
