Wake slow waves detected during resting-state EEG represent promising early biomarkers for AD pathology and amyloid conversion, facilitating risk stratification before cognitive decline onset.
Key Findings
Results
Individuals with amyloid and/or neurodegeneration pathology exhibited lower delta wake slow wave density compared to biomarker-negative participants.
Study population was 274 older adults with subjective cognitive decline (SCD) from the INSIGHT-preAD cohort (76.6 ± 3.5 years)
A+N-, A-N+, and A+N+ individuals all showed lower delta wake SW density than A-N- participants
High-density resting-state EEG was used to detect wake slow waves
PET scans assessed amyloid (A) and neurodegeneration (N) status
Results
Wake slow wave amplitude was higher in individuals with both amyloid and neurodegeneration pathology (A+N+) compared to biomarker-negative (A-N-) individuals.
The A+N+ group showed significantly higher wake SW amplitude than the A-N- group
This finding suggests that wake SW amplitude and density provide complementary information about AD pathological status
Both amplitude and density of wake SW were examined as potential biomarkers
Results
Wake slow wave amplitude correlated with poorer memory performance in older adults with subjective cognitive decline.
Higher wake SW amplitude was associated with worse memory outcomes
Participants were cognitively unimpaired at the time of assessment, having only subjective cognitive decline
Cognitive assessments were conducted alongside EEG and PET imaging
Results
Wake slow wave amplitude predicted conversion from amyloid-negative to amyloid-positive status over a two-year follow-up period.
Analysis included 157 amyloid-negative stable individuals and 16 converters
PET biomarkers were reassessed 2 years after baseline
Wake SW amplitude at baseline predicted subsequent A- to A+ conversion
This predictive capacity was present before cognitive decline onset
Background
Wake slow waves, described as sleep-like slow waves reflecting local intrusions of sleep during wakefulness, had not previously been explored in Alzheimer's disease research.
Growing evidence supports a critical role of sleep slow waves in AD, but wake SW remained unexplored
Wake SW are conceptualized as potentially reflecting local intrusions of sleep during waking states
High-density resting-state EEG was the recording modality used to detect these events
The study represents a novel application of wake SW detection in a preclinical AD population
Methods
The study used the INSIGHT-preAD cohort of older adults with subjective cognitive decline as the study population.
Total sample size was 274 participants
Mean age was 76.6 ± 3.5 years
All participants had subjective cognitive decline (SCD) but were not clinically impaired
Participants underwent PET for amyloid and neurodegeneration, high-density resting-state EEG, and cognitive assessments
What This Means
This research suggests that unusual brain wave patterns detected during waking rest — called 'wake slow waves' because they resemble the slow waves normally seen during sleep — may serve as early warning signals for Alzheimer's disease. The study recorded brain electrical activity using EEG in 274 older adults who felt their memory was slipping but had no formal diagnosis of cognitive impairment. The researchers found that people who already had biological signs of Alzheimer's disease (amyloid plaques or brain cell loss, detected by PET scans) showed different patterns of these wake slow waves — specifically lower density but higher amplitude — compared to those with no such biological signs.
Perhaps most notably, the amplitude of these wake slow waves at the start of the study predicted which participants would go on to develop amyloid accumulation in the brain two years later, even among people who initially had no detectable amyloid. Higher wake slow wave amplitude was also linked to worse memory performance. This suggests these EEG patterns may reflect early disruptions in brain function that precede or accompany the buildup of Alzheimer's-related proteins.
This research matters because identifying Alzheimer's disease at the earliest possible stage — before symptoms appear — is critical for any future preventive treatments. EEG is a relatively accessible, non-invasive, and lower-cost technology compared to PET scanning. If wake slow waves can reliably signal early Alzheimer's pathology and predict disease progression, they could potentially be used as a practical screening or monitoring tool to identify people at higher risk, helping to prioritize who might benefit most from further testing or early intervention strategies.
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Champetier P, Albero C, Raposo Pereira F, Herzog R, Chaumon M, Houot M, et al.. (2026). Sleep-like slow waves during resting-state: A promising EEG biomarker of amyloid and neurodegeneration in preclinical Alzheimer's disease.. Alzheimer's & dementia : the journal of the Alzheimer's Association. https://doi.org/10.1002/alz.71514