Quantified electroencephalographic changes in depressed patients with and without dementia

Area of Science:

• Neuroscience
• Psychiatry
• Gerontology

Background:

• Alzheimer's disease (AD) is a progressive neurodegenerative disorder.
• Depression is a common comorbidity in AD patients, potentially affecting disease presentation and progression.
• Quantified electroencephalograms (qEEG) offer insights into brain electrical activity.

Purpose of the Study:

• To investigate and compare qEEG differences between patients with probable AD and depression, AD without depression, depression without AD, and healthy controls.
• To identify specific qEEG markers associated with comorbid depression in Alzheimer's disease.

Main Methods:

• Quantified electroencephalograms (qEEG) were performed on four groups: probable AD with depression (n=17), probable AD without depression (n=18), depression without AD (n=13), and age-matched normal controls (n=10).
• Statistical analyses focused on relative power in alpha and delta frequency bands across different brain regions.

Main Results:

• Depressed patients (with or without AD) exhibited significantly lower right posterior alpha relative power compared to nondepressed patients.
• Depressed non-AD patients showed a global decrease in delta power, while depressed AD patients displayed increased delta power in posterior regions.
• qEEG findings in depressed AD patients were significantly different from those in depressed non-AD patients.

Conclusions:

• Comorbid depression in Alzheimer's disease is associated with distinct qEEG alterations in alpha and delta power.
• These qEEG differences may serve as potential biomarkers to differentiate depressed AD patients from depressed individuals without AD.
• Further research is warranted to explore the clinical implications of these neurophysiological findings.