EEG coherence in Alzheimer disease

Area of Science:

• Neuroscience
• Neurology
• Biomedical Engineering

Background:

• Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline.
• Electroencephalography (EEG) measures brain electrical activity, and coherence analysis can reveal functional connectivity between brain regions.
• Previous studies suggest alterations in brain connectivity in AD, but detailed analysis across specific frequency bands and derivations is needed.

Purpose of the Study:

• To investigate EEG coherence patterns in different frequency bands at multiple electrode locations in individuals with Alzheimer's disease compared to healthy controls.
• To identify specific brain regions and frequency bands most affected by reduced coherence in Alzheimer's disease.

Main Methods:

• A novel approach was used to analyze EEG coherence at 17 locations based on the 10-20 International System.
• EEG data were collected from 50 patients diagnosed with Alzheimer's disease and 42 age-matched non-demented controls.
• Average coherence was calculated between each electrode and its neighboring electrodes across theta, alpha, and beta frequency bands.

Main Results:

• EEG coherence was significantly decreased in patients with Alzheimer's disease compared to controls.
• The most pronounced reductions in coherence were observed in the frontal and central derivations.
• These coherence deficits were evident across the theta, alpha, and beta frequency bands.

Conclusions:

• The findings suggest widespread disruptions in functional brain connectivity in Alzheimer's disease.
• Reduced EEG coherence in specific frequency bands and derivations likely reflects underlying neuronal loss and neocortical disconnection.
• EEG coherence analysis offers a valuable tool for understanding the neurophysiological underpinnings of Alzheimer's disease.