Investigating Frontal Brain Asymmetry via EEG as a Predictor of Responsivity to a Brief Analogue Intervention Among Individuals with Public Speaking Anxiety
Authors:   , Fischer Laura Elizabeth , Herbert James D. , Forman Evan M. 
Published: July 2021

Public Speaking Anxiety (PSA) is a common and impairing psychological condition, causing significant distress and interference in multiple domains of functioning. Acceptance and Commitment Therapy (ACT) has demonstrated efficacy treating several psychological disorders, and preliminary evidence supports its efficacy for PSA. However, there is no prior research examining the neurological changes associated with ACT for individuals with PSA. Electroencephalogram (EEG) is a useful technique for examining baseline resting state patterns of brain electrical activity in addition to changes that may occur following a course of treatment. In addition, frontal alpha asymmetry has been shown to be related to approach/avoidance behaviors that may be indicative of changes in PSA symptomatology. Analogue interventions can serve as "mini" doses of treatment, potentially allowing researchers to quickly determine the efficacy of a treatment for an individual prior to embarking on a lengthy course of therapy. The present study is the first to examine the role of frontal brain asymmetry among individuals with PSA receiving a brief, acceptance-based analogue intervention. Specifically, we sought to determine whether greater left frontal hemispheric activity at baseline predicted response to an ACT analogue treatment. We enrolled 33 participants with public speaking anxiety, collecting clinician-rated and self-rated baseline assessments of symptomatology. Baseline resting state frontal alpha asymmetry was recorded using EEG, followed by a second EEG recording in which participants were asked to anticipate giving a brief public speech immediately afterward. Following an initial public speaking task, participants were shown a 30minute, video-recorded, acceptance-based intervention introducing concepts derived from ACT. Following the intervention, a third EEG recording was made, in which participants were asked to anticipate giving a second public speech, utilizing the skills they learned during the intervention. Immediately following this recording period, participants delivered a second public speech to a small audience. Response to treatment was quantified using participants' self-reported ratings of anxiety and "openness to anxiety" recorded during the pre- and post-treatment public speaking tasks. Results indicate that individuals with greater baseline anxiety symptomatology demonstrated greater increases in relative right hemispheric activity in anticipation of the pre-treatment public speaking task. Overall, the sample demonstrated a trend toward greater relative left frontal hemispheric activity across the three EEG time points, although this change did not reach statistical significance. Although no measure of frontal asymmetry was able to predict response to treatment, participants reported statistically significant anxiety reduction and increases in openness to anxiety, providing support for the utility of analogue interventions. Implications of the findings are discussed, and recommendations for future research are provided.