Targeting Method for rTMS for Treating Depression in Japanese Patients: A Comparison of the Standard, F3, and Neuronavigation Approaches

Introduction: The left dorsolateral prefrontal cortex (lDLPFC) is a commonly targeted brain region for repetitive transcranial magnetic stimulation (rTMS) for depression. The lDLPFC has been identified using the “5-cm rule.” However, identification of the lDLPFC may deviate from the ideal stimulation site localized by neuronavigation. Therefore, we aimed to compare this method with other methods and examine the relationship between deviation from the ideal stimulation site and treatment effects. While most existing studies have focused on participants of European descent, this study focused on Japanese participants. Methods: The study participants were 16 patients who underwent rTMS and had the stimulus location identified using the 5-cm method. The lDLPFC was identified by the F3 electrode position and neuronavigation in addition to the 5-cm rule, and these locations were compared. We then performed a correlation analysis of the distance between the sites identified by the 5-cm method and by neuronavigation, as well as changes in scores on the 17-item Hamilton Depression Scale (HAMD-17). Results: The lDLPFC identified by the F3 site and neuronavigation was approximately 3 cm more anterolateral than that identified by the 5-cm method. A significant correlation was found between the distance between the sites identified by the 5-cm method and neuronavigation and the rate of change in HAMD-17 scores. Conclusion: The ideal stimulation site may be approximately 3 cm anterior to the site identified by the 5-cm method, and stimulation of the F3 site may be a valid alternative to the 5-cm method.