This study by Diaz-Fong et al. (2025) plans to investigate body dysmorphic disorder (BDD), an understudied psychiatric condition marked by distortions in the perception of a patients’ physical appearance. The authors build on evidence that perceptual symptoms in BDD are underpinned by attentional biases, which may relate to abnormal visual processing and neural connectivity in the dorsal visual stream (DVS; reduced activation) and the ventral visual stream (VVS; increased activation). Prior evidence suggests that activation in the DVS and the VVS may be modifiable by both non-invasive neuromodulation (including transcranial magnetic stimulation), as well as behavioural interventions such as the Visual Modification (ModV) paradigm, which has been suggested to reduce patients’ foveal attention to perceived bodily defects. The ModV paradigm has been specifically linked with altered VVS and DVS activation and connectivity. 

 

Here the authors will test in a within-subject crossover design (N = 40) whether neural connectivity and visual perceptual biases in BDD and subclinical BDD can be modified by combining the effects of altered visual attention in the ModV paradigm with repetitive transcranial magnetic stimulation (continuous and intermittent theta burst stimulation; cTBS and iTBS). By combining a behavioural and an exogenous intervention, the authors predict an increase in the magnitude of clinically meaningful improvements in attentional biases in BDD, with iTBS expected to enhance, and cTBS expected to inhibit the effects of visual attention modification through ModV on neural connectivity (measured using fMRI) and visual processing. More specifically, the effect of TBS is hypothesised to be stronger after patients perform ModV.

 

The Stage 1 manuscript was evaluated by two experts who performed in-depth peer review across multiple rounds of revisions. The authors were responsive in editing their manuscript based on the reviewers’ comments and dedicated much effort to increasing the clarity and interpretability of their power analyses. The revised manuscript was judged to meet the Stage 1 criteria and was awarded in-principle acceptance (IPA). 

URL to the preregistered Stage 1 protocol: https://osf.io/ks425 (under temporary private embargo)
 
Level of bias control achieved: Level 3. At least some data/evidence that will be used to the answer the research question has been previously accessed by the authors (e.g. downloaded or otherwise received), but the authors certify that they have not yet observed any part of the data/evidence.
 
List of eligible PCI RR-friendly journals:

 

 

 

Diaz-Fong, J. P., Lewis, M., Qian, J., Wong, W.-W., Leuchter, A. F., Tadayonnejad, R., Voineskos, D., Konstantinou, G., Lam, E., Blumberger, D. M., Feusner, J. D. (2025). Noninvasive neuromodulation of visual perception and neural connectivity in body dysmorphic disorder: a registered report. In principle acceptance of Version 3 by Peer Community in Registered Reports. https://osf.io/ks425