Electroencephalogram alpha asymmetry in geriatric depression : Valid or vanished?

Abstract

Background: A correlation between asymmetry in electroencephalographs (EEG) and depression has been demonstrated in many studies. To the best of our knowledge there are no studies including oldest old geriatric patients.

Objective: The objective of this study was to evaluate whether frontal and parietal alpha asymmetry can be used to differentiate between depressed and control patients in a cohort sample with a mean age of 80 years.

Material and methods: Differences in the EEG were investigated in 39 right-handed female geriatric patients (mean age 80 years) with respect to frontal alpha asymmetry (FAA) and parietal alpha asymmetry (PAA) in depression (n = 14), depression combined with anxiety (n = 11) and normal controls (n = 14) as assessed with the hospital anxiety and depression scale (HADS). Band power was calculated for alpha 1 (6.9-8.9 Hz), alpha 2 (8.9-10.9 Hz) and alpha 3 bands (10.9-12.9 Hz). Furthermore, correlations between frontal and parietal alpha asymmetry and the geriatric depression scale (GDS), the HADS and the mini mental state examination (MMSE) were calculated.

Results: A differentiation between the three groups was not possible with FAA and PAA. Significant correlations were found between PAA alpha 3 band and anxiety and depression.

Conclusion: The alpha asymmetry in EEG seemed to disappear with age. Correlations between PAA and anxiety and depression were found. The results are in line with the right (hemisphere) hemi-aging hypothesis.

Keywords: Aging; Anxiety; Depression; Electroencephalogram; Gerontology.