MINI REVIEW article
Front. Hum. Neurosci.
Sec. Brain Health and Clinical Neuroscience
EEG Alpha Reactivity in Cognitive Aging: A Review on Clinical Implications and Potential Cholinergic Mechanisms
Provisionally accepted
- Pusan National University, Busan, Republic of Korea
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Alpha reactivity—the attenuation of the alpha rhythms upon eye-opening—is a well-known phenomenon in electroencephalography (EEG). Altered alpha reactivity has increasingly been recognized as a potential biomarker for cognitive aging and various types of dementia. This mini-review synthesizes the existing literature on EEG alpha reactivity in older adults, highlighting its clinical implications and neurobiological underpinnings. Methodological issues in quantifying alpha reactivity are first addressed, including the choice of reactivity index, frequency bands, and spatial analysis methods. The review then summarizes evidence that alpha reactivity declines with healthy aging and is further reduced in dementia, especially Alzheimer's disease (AD) and Lewy body dementia (LBD). Importantly, distinct patterns of reduced alpha reactivity may aid in differential diagnosis. It has been reported that AD is often characterized by reduced alpha rhythm during eyes-closed rest, whereas LBD typically shows impaired alpha attenuation upon eye-opening. Neuroimaging and pharmacological studies suggest that alpha reactivity reflects cholinergic system integrity, particularly involving the nucleus basalis of Meynert and its projections to the visual cortex. In conclusion, EEG alpha reactivity is a promising, non-invasive biomarker of cognitive health and dementia subtypes. However, larger, harmonized, multimodal and longitudinal studies are needed to establish its diagnostic value and clarify its neurobiological mechanisms.
Keywords: Aging, alpha reactivity, Alzheimer's disease, Dementia, Electroencephalography, Lewy body dementia, nucleus basalis of Maynert, Posterior dominant rhythm
Received: 14 Jul 2025; Accepted: 16 Jan 2026.
Copyright: © 2026 Baek. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Kwangyeol Baek
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