Temporal stability of posterior EEG alpha over twelve years
Craig E. Tenke1,2,3, Jürgen Kayser1,2,3, Jorge E. Alvarenga1, Karen S. Abraham1, Virginia Warner2,4, Ardesheer Talati2,3,4, Myrna M. Weissman2,3,4, Gerard E. Bruder1,3
1Division of Cognitive Neuroscience, New York State Psychiatric Institute, New York, NY, USA; 2Division of Epidemiology, New York State Psychiatric Institute, New York, NY, USA; 3Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA; 4Columbia University, Mailman School of Public Health, New York, NY, USA
Received 22 November 2017; revised 14 March 2018; accepted 20 March 2018; published online 16 April 2018.
Abstract
Objective: We previously identified posterior EEG alpha as a potential biomarker for antidepressant treatment response. To meet the definition of a trait biomarker or endophenotype, it should be independent of the course of depression. Accordingly, this report evaluated the temporal stability of posterior EEG alpha at rest.
Methods: Resting EEG was recorded from 70 participants (29 male; 46 adults), during testing sessions separated by 12 ±1.1 years. EEG alpha was identified, separated and quantified using reference-free methods that combine current source density (CSD) with principal components analysis (PCA). Measures of overall (eyes closed-plus-open) and net (eyes closed-minus-open) posterior alpha amplitude and asymmetry were compared across testing sessions.
Results: Overall alpha was stable for the full sample (Spearman-Brown [rSB] = .834, Pearson's r = .718), and showed excellent reliability for adults (rSB = .918; r = 0.848). Net alpha showed acceptable reliability for adults (rSB =.750; r = .600). Hemispheric asymmetries (right-minus-left hemisphere) of posterior overall alpha showed significant correlations, but revealed acceptable reliability only for adults (rSB = .728; r = .573). Findings were highly comparable between 29 male and 41 female participants.
Conclusions: Overall posterior EEG alpha amplitude is reliable over long time intervals in adults.
Significance: The temporal stability of posterior EEG alpha oscillations at rest over long time intervals is indicative of an individual trait.
Key Words: EEG; temporal stability; trait biomarker; surface Laplacian; current source density (CSD); principal components analysis (PCA)