EEG Microstate Alterations in Alzheimer’s Disease: Emerging Evidence for a Potential Biomarker

Brain activity is inherently dynamic, even during conditions of “rest”, and deviations in these dynamics have been linked to various pathological states and neurodegenerative conditions including Alzheimer’s disease (AD). AD is characterized by the accumulation of amyloid-beta plaques and tau tangles, both of which disrupt brain function and contribute to cognitive and behavioural impairment. Although no cure exists to date, significant progress has been made in identifying reliable biomarkers to improve early detection, diagnostic accuracy, monitoring of disease progression and severity, and evaluation of treatment outcomes. Electroencephalography (EEG) offers a non-invasive and cost-effective approach to record brief, stable patterns of electrical brain activity—or microstates—which may serve as novel disease-specific biomarkers in AD. With EEG microstate analysis, it is possible to gain insight into the altered temporal organization of brain activity that characterizes AD, and potentially facilitate therapeutic interventions at critical stages of disease progression. Therefore, this review explores the current state of research on the application of microstate analysis in AD, highlighting its potential for understanding disease mechanisms and serving as a functional biomarker. Furthermore, the existing challenges, clinical implications and recommendations for future direction are discussed with the aim to advance the role of EEG microstates in clinical practice to detect, diagnose, monitor and manage AD.