Responsivity to an Analogue Psychological Acceptance Task and Neurophysiological Measures as Predictors of Treatment Response for Public Speaking Anxiety
Authors:   , Berkowitz Staci A. , Herbert James D. 
Published: July 2021

Background: Individuals seeking treatment for mental health conditions often explore multiple therapeutic modalities before finding one that is beneficial. Early identification of individuals likely to respond to a particular psychotherapy modality may substantially decrease this burden. Objective: The current study tested novel variables as potential predictors of response to psychotherapy for public speaking anxiety (PSA). Specifically, the current study (1) evaluated whether responsivity to a laboratory-based analogue intervention for acceptance and commitment therapy (ACT) predicted subsequent treatment response to an actual ACT-based intervention, and (2) evaluated whether frontal brain activity (frontal asymmetry; bilateral activity) at baseline or (3) in anticipation of public speaking predicted subsequent treatment response. Participants: A total of 48 individuals with PSA completed all study components. Methods: Participants completed a public speaking task prior to and following receipt of a brief ACT-based analogue intervention. In association with each public speaking task, neurophysiological measurements, including frontal brain activity measured by electroencephalography (EEG) and heart rate (HR), were collected. Analogue intervention responsivity was considered based on residualized change in self-reported anxiety and openness to anxiety, neurophysiological measurement (EEG; HR), behavioral ratings of speech performance, and an analogue responsivity composite factor. Participants subsequently received a 2.5 hour ACT treatment over two days. A final public speaking task was completed and psychological, physiological (HR), and behavioral ratings were collected as primary measures of treatment outcome, along with a composite treatment outcome factor. Results: The analogue responsivity composite factor predicted ACT treatment outcome on several measures, with greater analogue intervention symptom improvement associated with greater subsequent ACT treatment symptom improvement on most measures. Individual analogue responsivity variables generally did not predict ACT treatment responsivity. Greater right-frontal asymmetry at baseline and in anticipation of a public speaking task trended towards an association with greater symptom improvement over treatment across several outcome measures. Greater bilateral frontal activity - a measure associated with self-reported mindfulness at baseline - significantly predicted greater symptom improvement over treatment across several outcome measures; higher mindfulness at baseline also predicted greater symptom improvement across several outcome measures. Implications: Findings suggest that an individual's response to an analogue intervention, or a small 'dose' of psychotherapy, may inform their response to a longer course of psychotherapy, particularly in ACT for PSA. Individuals with greater bilateral frontal activity and (to a lesser degree) individuals with greater right-frontal asymmetry may experience greater symptom reduction in an ACT-based treatment for PSA. Future studies should evaluate whether any of these variables (analogue responsivity; frontal brain activity) differentially predict response to two or more different psychotherapies in a quest towards personalized medicine. Future research should also evaluate whether interventions designed to increase baseline mindfulness (e.g., meditation training) prior to a course of ACT for PSA, or a similar intervention, improves treatment efficacy.