EEG Asymmetry and its Clinical Correlates in PTSD

Proposal details

Title: EEG Asymmetry and its Clinical Correlates in PTSD
Research Area(s): PTSD and other Anxiety Disorders
Background: The approach/withdrawal model is a neuropsychological model of emotion and emotional disorders that proposes that particular patterns of EEG alpha asymmetry are associated with motivation to approach positive stimuli or motivation to withdraw from negative stimuli. The model also proposes that individuals with depression are characterized by low motivation to approach (and a relative decrease in left frontal EEG activity) and individuals with anxiety are characterized by high motivation to withdrawal (and a relative increase in right frontal EEG activity). While there is a fairly extensive literature testing these hypotheses in individuals with depression and some anxiety disorders, no study has examined the EEG asymmetry in individuals with PTSD. This question is particularly important as there is some debate as whether PTSD is a disorder of low approach motivation (and thus like depression) or a disorder of high withdrawal motivation (and thus like anxiety).
Aims: The primary aim of the proposed data analyses is to compare individuals with PTSD with controls on EEG alpha asymmetry. A related secondary aim of the study is to examine whether particular patient characteristics relate to EEG asymmetry more than others. Specifically, we will look at when the trauma occurred, and scores on Lovibond and Lovibond's DAS (depression anxiety stress scale). A third aim of the study is to match individuals with PTSD and controls on personality scores from the NEO (e.g., neuroticism and extraversion) in order to determine whether the group differences on EEG asymmetry are due to personality differences between the two diagnostic groups.
Method: Resting EEG was recorded from participants with their eyes open and eyes closed. The average absolute alpha power will be extracted from the EEG using a Fast Fourier Transform. The groups will be compared on the relative difference of alpha power of homologous electrodes (e.g., F3 vs F4).