Frontal brain asymmetry in depression with comorbid anxiety: A neuropsychological investigation

1997

Background: Studies using electroencephalogram (EEG) measures of activation asymmetry have reported differences in anterior asymmetry between depressed and nondepressed subjects. Several studies have suggested reciprocal relations between measures of anterior and posterior activation asymmetries. We hypothesized that depressed subjects would fail to show the normal activation of posterior right hemisphere regions in response to an appropriate cognitive challenge. Methods: EEG activity was recorded from 11 depressed and 19 nondepressed subjects during the performance of psychometrically matched verbal (word finding) and spatial (dot localization) tasks. Band power was extracted from all epochs of artifact-free data and averaged within each condition. Task performance was also assessed. Results: Depressed subjects showed a specific deficit in the performance of the spatial task, whereas no group differences were evident on verbal performance. In posterior scalp regions, nondepressed controls had a pattern of relative left-sided activation during the verbal task and relative right-sided activation during the spatial task. In contrast, depressed subjects failed to show activation in posterior right hemisphere regions during spatial task performance. Conclusions: These findings suggest that deficits in right posterior functioning underlie the observed impairments in spatial functioning among depressed subjects.

Biological Psychology, 2007

Frontal asymmetry of EEG alpha power (FA) may index the risk for anxiety and depression. Evidence linking FA to the underlying biological mechanisms is scarce. This is unfortunate because FA has potential as a biological marker to support gene finding in anxiety and depression. We examined the heritability of FA in 732 twins and their singleton siblings, and established the genetic and environmental contribution to the relation between FA and the risk for anxiety and depression. Multivariate models showed that FA is heritable only in young adults (males 32% and females 37%) but not in middle-aged adults. A significant relation between FA and the risk for anxiety and depression was only found in young adult females. This relation was explained by shared genes influencing both EEG and disease risk. Future studies on asymmetry of left and right frontal brain activation should carefully consider the effects of sex and age. #

Journal of Affective Disorders, 2011

Psychophysiology, 2011

Relatively less right parietal activity may reflect reduced arousal and signify risk for major depressive disorder (MDD). Inconsistent findings with parietal electroencephalographic (EEG) asymmetry, however, suggest issues such as anxiety comorbidity and sex differences have yet to be resolved. Resting parietal EEG asymmetry was assessed in 306 individuals (31% male) with (n=143) and without (n=163) a DSM-IV diagnosis of lifetime MDD and no comorbid anxiety disorders. Past MDD+ women displayed relatively less right parietal activity than current MDD+ and MDD- women, replicating prior work. Recent caffeine intake, an index of arousal, moderated the relationship between depression and EEG asymmetry for women and men. Findings suggest that sex differences and arousal should be examined in studies of depression and regional brain activity.

2011

Psychophysiology, 2014

The capability model of frontal electroencephalographic (EEG) asymmetry suggests that brain activity during emotional challenge will be a more powerful indicator of predispositions toward psychopathology than activity observed at rest. EEG data were assessed during a resting baseline and a facial emotion task, wherein individuals with (n = 143) and without (n = 163) lifetime major depressive disorder (MDD) made approach (angry and happy) and withdrawal (afraid and sad) facial expressions. EEG asymmetry during emotional challenge was a more powerful indicator of MDD status than resting asymmetry for average, Cz, and linked mastoid references, results in support of the capability model. However, current-source-density (CSD) transformed asymmetry was indicative of lifetime MDD status under resting and task-elicited conditions. Findings suggest that CSD-transformed data may be more robust indicators of trait frontal EEG asymmetry.

Journal of abnormal …, 2010

Biological Psychology, 2008

2010

InTech eBooks, 2017

There are three major hypotheses regarding the lateralization of emotion in the brainthe right-hemisphere hypothesis (RHH), the valence hypothesis, and the approachwithdrawal hypothesis. The approach-withdrawal hypothesis, which is the most widely accepted, states that emotions that elicit approach behaviors are lateralized to the left hemisphere, while emotions that elicit withdrawal behaviors are lateralized to the right hemisphere. In line with this hypothesis, it has been found that persons with depression show left frontal hypoactivity and right frontal hyperactivity. This hemispheric asymmetry appears not to influence mood but rather emotional reactions to affective stimuli. That is, a person with such an asymmetry does not show a predominant negative mood, but rather heightened negative reactions to occurrences in the environment. The asymmetry may also be a biological marker of depression, with research evidence that it is found in remitted depressives and in infants of depressed mothers. Currently, research in this area focuses on identifying the mechanism underlying the link between the asymmetry and depression.

Psychophysiology, 2010

Although numerous EEG studies have shown that depression is associated with abnormal functional asymmetries in frontal cortex, fMRI and PET studies have largely failed to identify specific brain areas showing this effect. The present study tested the hypothesis that emotion processes are related to asymmetric patterns of fMRI activity, particularly within dorsolateral prefrontal cortex (DLPFC). Eleven depressed and 18 control participants identified the color in which pleasant, neutral, and unpleasant words were printed. Both groups showed a leftward lateralization for pleasant words in DLPFC. In a neighboring DLPFC area, the depression group showed more right-lateralized activation than controls, replicating EEG findings. These data confirm that emotional stimulus processing and trait depression are associated with asymmetric brain functions in distinct subregions of the DLPFC that may go undetected unless appropriate analytic procedures are used.

Journal of Abnormal Psychology, 2000

This study examined whether adolescents with major depressive disorder (MDD) display the abnormal electroencephalographic (EEG) alpha asymmetries found in depressed adults. Resting EEG was recorded in 25 right-handed female outpatients (19 with MDD, 11 of whom also had a current anxiety disorder; 6 with anxiety disorders only) and 10 non-ill controls. In contrast to the non-ill controls, adolescents having MDD but no anxiety disorder showed alpha asymmetry indicative of less activation over right than over left posterior sites. Within the MDD patient group, comorbid anxiety disorders reduced the posterior alpha asymmetry, supporting the potential importance of evaluating anxiety in studies of regional brain activation in adolescent MDD. These preliminary findings are similar to those from adult studies that suggest that MDD is associated with right parietotemporal hypoactivation.

Scandinavian Journal of Psychology, 2012

Electroencephalographic (EEG) frontal alpha asymmetry (FAA) and frontal midline (FM) theta have been suggested as biomarkers for depression and anxiety, but have mostly been assessed in small and non‐clinical studies. In a clinical sample of 79 adults with depression (ICD‐10: F32), resting EEG and scales of depression (MADRS) and anxiety (HADS‐A) were measured at intake and after 3 months. FAA and FM theta values were referenced to a normative population database. Internal consistency, test‐retest reliability, and correlations with psychiatric tests were examined. Reliability was sufficient. However, FAA and FM theta values were close to the general population, and correlations with psychiatric tests were mostly small and non‐significant, with the exception of FAA on F7–F8 z‐scores and HADS‐A. We conclude that the validity of FAA and FM theta and therefore their potential as biomarkers for depression and anxiety remain unclear.

Frontiers in Psychiatry, 2010

Background: Impaired cognitive control functions have been demonstrated in both major depression (MDD) and anxiety disorder (A), but few studies have systematically examined the impact of MDD with co-morbid A (MDDA), which is the main aim of this study. Method: We compared patients with MDD with (MDDA; n = 24) and without co-morbid A (n = 37) to a group of healthy controls (HC; n = 92) on three subtests from the Cambridge Neuropsychological Test Automated Battery; intra-extra dimensional, stop signal task, and spatial working memory. These tasks correspond to a theoretical model consisting of three separable but interrelated executive control functions: Shifting, Inhibition, and Updating. A simple psychomotor speed measure was also included. Results: After controlling for age, gender, and education level, the results showed that the MDDA group displayed significantly impaired performance on the functions Shifting and Updating compared to HC. There emerged no significant differences between any of the patient groups and HC regarding Inhibition. The pure MDD group did not display dysfunctions relative to the HC group on the main executive control variables, but displayed slowed psychomotor speed. Contrary to expectation there were no significant differences between the MDDA and the MDD groups. Conclusion: Co-morbid anxiety should be taken into account when studying cognitive control functions in major depression.

Neuroscience Letters, 2009

The proposal that a functional asymmetry in prefrontal cortex (PFC) may play a role in the pathophysiology of depression has sparked vigorous debate and investigation. One particularly contentious issue of clinical and theoretical importance is whether left PFC lesions are associated with the development of depression, and whether any such lesion-depression association is stable over time. To address this issue, we assessed the long-term depressive symptomotology of Vietnam veterans who had acquired left PFC lesions (n=21), right PFC lesions (n=18), non-PFC lesions (n=38), or no brain lesions (n=31) during the Vietnam War. Depressive symptoms were assessed at two different timepoints, approximately 15 and 35 years after lesion onset, respectively. There was no significant effect of PFC lesion laterality on overall depression severity at either timepoint. These data converge with previous stroke studies to suggest that PFC lesion laterality has no long-term systematic effect on vulnerability to depression.