Exploring Alpha Desynchronization in Alzheimer's Disease Using Coherence Analysis

Electroencephalography (EEG) is a promising tool for early diagnosis of dementia. As the most common form of dementia, Alzheimer's disease (AD) is currently incurable, but patients and those at risk can benefit from timely intervention following accurate diagnosis. Previous studies reported decreased energy in the alpha-band of EEG signals during the transition from the eyes-closed condition to the eyes-open condition, and considered energy as a surrogate index of synchronization (or functional connectivity). In this study, we explored alpha desynchronization by using coherence which is a mathematical index of connectivity. Our results showed that the AD group had lower alpha-band energy and coherence, and diminished alpha desynchronization as compared with the normal control group. Coherence and energy have different implications in synchronization/connectivity (long-range vs. local), and when combined, may advance the understanding of AD pathology-related functional connectivity changes.Clinical Relevance- This study highlights diminished alpha desynchronization in patients with Alzheimer's disease, which may be used as a biomarker for early diagnosis.