Augmentative effects of tDCS on a body-related attentional retraining in women with bulimia nervosa
Final Report Abstract
Biased processing of body-related information is assumed to maintain high body dissatisfaction (BD) and eating disorder pathology. Indeed, several studies have shown a strong attention bias (AB) towards self-defined unattractive relative to attractive body parts when looking at the own body in individuals with high BD. In our project, we investigated processing of the self-body in a sample of women with (subthreshold) bulimia nervosa (BN) and/or high BD (BD group, N = 95) compared to a group of women with low BD (control group, N = 40). First, we replicated the AB in the BD relative to the control group by recording eye movements while looking at pictures of the own body. Further, BD and control group differed regarding processing of the self-body on a neurophysiological level as indicated by increased amplitudes of concurrently assessed event-related potentials (ERPs, i.e., early posterior negativity [EPN]) when the three self-defined most unattractive body parts were first fixated. Preliminary analyses yielded an increased activity in the dorsolateral prefrontal cortex (dlPFC) when processing the self-defined most unattractive body parts as assessed via functional near-infrared spectroscopy (fNIRS) in an additional paradigm, which, however, did not differ between groups. To test the assumed causal role of biased information processing in BD, we further investigated the efficacy of a personalized attention bias modification training (ABMT) that implicitly guided attention to self-defined attractive body parts compared to a control training that directed attention to self-defined medium (un)attractive body regions. Furthermore, we explored possible augmentative effects of simultaneous transcranial direct current stimulation (tDCS; active vs. sham) of the dlPFC, since tDCS has been shown to enhance short-term effects of ABMT on attention processes. N = 85 women of the BD group participated in 12 training sessions (min. 20 per group: ABMT + sham, ABMT + active, control training + sham, control training + active). Self-reported BD was assessed at baseline, post-treatment and in a 4- and 12-week follow-up. While BD significantly declined over time across groups, there was no significant interaction of training × tDCS × time, nor were there any other significant twoway interactions or main effects. Furthermore, there we no changes from pre to post in bodyrelated attentional and neurophysiological processes.
