No relationship between frontal alpha asymmetry and depressive disorders in a multiverse analysis of five studies.

Aleksandra Kołodziej,Aneta Brzezicka,Mikołaj Magnuski,Anastasia Ruban

doi:10.7554/elife.60595

Aleksandra Kołodziej, Aneta Brzezicka + Show 2 more

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https://doi.org/10.7554/elife.60595

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Abstract

For decades, the frontal alpha asymmetry (FAA) - a disproportion in EEG alpha oscillations power between right and left frontal channels - has been one of the most popular measures of depressive disorders (DD) in electrophysiology studies. Patients with DD often manifest a left-sided FAA: relatively higher alpha power in the left versus right frontal lobe. Recently, however, multiple studies failed to confirm this effect, questioning its reproducibility. Our purpose is to thoroughly test the validity of FAA in depression by conducting a multiverse analysis - running many related analyses and testing the sensitivity of the effect to changes in the analytical approach - on data from five independent studies. Only 13 of the 270 analyses revealed significant results. We conclude the paper by discussing theoretical assumptions underlying the FAA and suggest a list of guidelines for improving and expanding the EEG data analysis in future FAA studies.

Highlights

Electrophysiological studies on frontal alpha asymmetry (FAA) in depressive disorders (DD) have almost 40 years of history, with first reports presented in 1983 (Schaffer et al, 1983)
Many studies have reported relatively higher alpha band power in the left vs right frontal channels in subjects suffering from DD compared to healthy individuals (Allen et al, 2004; Davidson, 1984; Davidson, 2004; Kemp et al, 2010; Schaffer et al, 1983)
The analysis variants making up the multiverse analysis can be classified along four major dimensions (Figure 2): (a) statistical contrast used: group comparisons or testing for a linear relationship, Neuroscience

Summary

Introduction

Electrophysiological studies on frontal alpha asymmetry (FAA) in depressive disorders (DD) have almost 40 years of history, with first reports presented in 1983 (Schaffer et al, 1983). Multiple studies failed to replicate the relationship between FAA and DD (Allen et al, 2004; Carvalho et al, 2011; Deldin and Chiu, 2005; Gold et al, 2013; Kaiser et al, 2018a; Kentgen et al, 2000; Knott et al, 2001; Mathersul et al, 2008; Szumska et al, 2021; Vuga et al, 2006) and conclusions of meta-analyses remain skeptical (Thibodeau et al, 2006; van der Vinne et al, 2017) In this light statements about FAA being a biomarker of depression (Baskaran et al, 2012; Iosifescu et al, 2009) seem to be too far-fetched. Correlated predictors like education and depression can reduce each other’s effect by explaining shared variance in the dependent variable, including confounding

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