Frontal brain asymmetry, childhood maltreatment, and low-grade inflammation at midlife

Abstract

Frontal EEG asymmetry is thought to reflect variations in affective style, such that greater relative right frontal activity at rest predicts enhanced emotional responding to threatening or negative stimuli, and risk of depression and anxiety disorders. A diathesis-stress model has been proposed to explain how this neuro-affective style might predispose to psychopathology, with greater right frontal activity being a vulnerability factor especially under stressful conditions. Less is known about the extent to which greater relative right frontal activity at rest might be associated with or be a diathesis for deleterious physical health outcomes. The present study examined the association between resting frontal EEG asymmetry and systemic, low-grade inflammation and tested the diathesis-stress model by examining whether childhood maltreatment exposure interacts with resting frontal asymmetry in explaining inflammation. Resting EEG, serum inflammatory biomarkers (interleukin-6, C-reactive protein, and fibrinogen) and self-reported psychological measures were available for 314 middle-aged adults (age M=55.3years, SD=11.2, 55.7% female). Analyses supported the diathesis-stress model and revealed that resting frontal EEG asymmetry was significantly associated with inflammation, but only in individuals who had experienced moderate to severe levels of childhood maltreatment. These findings suggest that, in the context of severe adversity, a trait-like tendency towards greater relative right prefrontal activity may predispose to low-grade inflammation, a risk factor for conditions with inflammatory underpinnings such as coronary heart disease.

Keywords: Child maltreatment; Inflammation; Resting frontal EEG asymmetry.

Figure 1

Data collection waves in the MIDUS (Midlife in the United States) study.

Figure 2

Right-sided frontal asymmetry (i.e., having a higher asymmetry score) was associated with more inflammation in those reporting high levels of maltreatment (top 40.8% of CTQ scores). The gray shaded area represents the region where the two lines differ significantly from each other. All variables were standardized, thus values represent Z-scores. Statistics for simple slopes are displayed next to each line.

Figure 3

Maltreatment was associated with higher levels of inflammation in those with high asymmetry scores (indicating right-sided dominance), roughly 1.15 SD above the mean on asymmetry or higher. All variables were standardized, thus values represent Z-scores. The gray shaded area represents the region where the two lines significantly differ.