Resting EEG partial coherence demonstrates increased γ range central functional connectivity in amnestic mild...

Area of Science:

• Neuroscience
• Biomarkers
• Electroencephalography (EEG)

Background:

• Alzheimer's disease (AD) research often overlooks high-frequency electroencephalography (EEG) changes.
• Understanding functional connectivity in the gamma (γ) frequency range is crucial for early detection of neurodegenerative conditions.

Purpose of the Study:

• To investigate alterations in EEG functional connectivity within the gamma frequency range in individuals with amnestic Mild Cognitive Impairment (MCI).
• To utilize Partial Coherence (PCOH) to enhance signal-to-noise ratio for high-frequency EEG analysis in MCI.

Main Methods:

• Resting-state EEG data were collected from 21 MCI patients and 62 cognitively normal (CN) individuals.
• EEG data were recorded with eyes closed (EC) and eyes open (EO) using a 10/20 montage with 19 active electrodes.
• Ordinary Coherence (COH) and Partial Coherence (PCOH) were calculated for all 171 electrode pairs across the 0.5-100 Hz range.

Main Results:

• Significantly higher PCOH values were observed in MCI patients compared to CN individuals in both γ1 (30-50 Hz) and γ2 (50-100 Hz) ranges.
• These differences were particularly prominent in central electrode pairs and across both eye conditions.
• Local connectivity analysis also revealed significantly higher central PCOH values in MCI compared to CN.

Conclusions:

• Resting EEG gamma-range functional connectivity, particularly in central brain areas as measured by PCOH, is significantly elevated in individuals with MCI.
• These findings suggest that gamma-range EEG functional connectivity metrics, like PCOH, can help identify neurodegenerative changes.
• PCOH, by factoring out global connectivity, may be a valuable tool for developing accessible biomarkers for neurodegeneration.