AUTHOR=Marcu Gabriela M. , Szekely-Copîndean Raluca D. , Radu Ana-Maria , Bucuță Mihaela D. , Fleacă Radu S. , Tănăsescu Ciprian , Roman Mihai D. , Boicean Adrian , Băcilă Ciprian I. 

TITLE=Resting-state frontal, frontlateral, and parietal alpha asymmetry:A pilot study examining relations with depressive disorder type and severity

JOURNAL=Frontiers in Psychology

VOLUME=Volume 14 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2023.1087081

DOI=10.3389/fpsyg.2023.1087081

ISSN=1664-1078

ABSTRACT=The search for biomarkers has been central to efforts of improving clinical diagnosis and prognosis in psychopathology in the last decades.  The main approach has been to validate biomarkers that could accurately discriminate between clinical diagnoses of very prevalent forms of psychopathology. One of the most popular electrophysiological markers proposed for discrimination in depressive disorders is the electroncephalography(EEG)-derived frontal alpha asymmetry. However, the validity, reliability and predictive value of this biomarker have been questioned in recent years, mainly due to  conceptual and methodological heterogeneity.  In the current non-experimental, corelational study we investigated relationship of resting-state EEG alpha asymmetry from multiple sites (frontal, frontolateral, parietal) with different forms of depressive disorders (varying in type or severity), in a clinical sample. Results showed that alpha asymmetry in the parietal (P3-P4) was significantly higher than in the frontal (F3-F4) and frontolateral sites (F7-F8).  However, we did not find significant relations between alpha asymmetry indices and our depressive disorder measures, except for a moderate positive association between frontolateral alpha asymmetry (eyes-closed only) and depressive disorder severity (determined through clinical structured interview).We also found no significant differences in alpha asymmetry between participants, depending on their depression type. Based on results, we propose the parietal and frontolateral asymmetry indices to form hypotheses that should not be abandoned in the depression markers research, but worth for further experimental research. Methodological and clinical implications of the current findings are discussed.