EEG Microstate Correlates of Emotional Processing in Patients with Alcohol use Disorder and Healthy Controls: An Exploratory Resting-EEG Study.

Emotion processing is a key domain in alcohol use disorder (AUD). Given the neuronal basis of emotion regulation and the neurophysiological deviations observed in AUD patients the present exploratory study investigates EEG Microstate (MS) correlates of emotional processing in patients with AUD and healthy controls (HC). Emotions, moods and emotion regulation competencies were assessed in 29 patients with AUD and 22 HC using self-report. Additionally, a 64-channel resting-state electroencephalography (EEG) was recorded for each individual and a microstate analysis yielding 7 classes (A-G) was performed. The effects of the factors group (patients with AUD vs. HC), emotion/emotion regulation (from self-report scales) and MS class (A-G) on the MS feature contribution were analyzed using linear models. Three-way interactions were observed for "awareness of feelings" (Bonferroni-corrected; F(6, 329) = 3.75, p = .001) and "shame" (F(6, 322) = 2.42, p = .026). Level of awareness of feelings correlated positively with MS C in HC, while an inverse correlation was found for MS D. No such association between awareness of feelings and MS C and D was observed in patients with AUD who rather displayed significantly higher overall MS C values than HC (tRatio(343) = -3.13, p = .002). The present study provides initial evidence that neuronal activity, as reflected in MSs, differs in relation to emotion processing between patients with AUD and healthy individuals. The results indicate that MS C and D might be neurophysiological markers for awareness of feelings in HC, while such an association is blunted in patients with AUD.