Electroencephalographic upper/low alpha frequency power ratio relates to cortex thinning in mild cognitive impairment

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Temporoparietal cortex thinning is linked to mild cognitive impairment (MCI) in Alzheimer's disease (AD).
• An elevated upper/lower alpha frequency power ratio in electroencephalography (EEG) is associated with MCI subjects who progress to AD.

Purpose of the Study:

• To investigate the relationship between the EEG upper/lower alpha frequency power ratio and cortical thickness patterns in individuals with MCI.
• To determine if EEG alpha frequency ratios can predict regional brain changes in MCI.

Main Methods:

• 74 adult subjects with MCI underwent clinical, neuropsychological, EEG, and MRI assessments.
• Cortical thickness and EEG alpha frequency power ratios were computed for all participants.
• MCI subjects were grouped into tertiles based on their EEG alpha frequency power ratios to compare cortical thickness patterns.

Main Results:

• Subjects with a high EEG upper/lower alpha frequency power ratio exhibited significantly greater total cortical grey matter volume reduction compared to those with a low ratio (p < 0.001).
• Widespread cortical thinning, particularly in the supramarginal gyrus and precuneus, was observed in the high EEG alpha ratio group.
• No significant regional cortical thickness differences were found between the middle and low EEG alpha ratio groups.

Conclusions:

• A high EEG upper/lower alpha frequency power ratio is associated with temporoparietal cortical thinning in MCI.
• Combining EEG alpha frequency power ratio and cortical thickness measurements may aid in identifying individuals at risk for progression to AD dementia.