Comparison of Modified Beam F3 with Scalp Geometry-Based Parameter (SGP) for Locating the DLPFC

Background: As the field of transcranial magnetic stimulation (TMS) evolves, there is still debate over optimal therapeutic target for effective treatment depression. Over time, it has become elucidated that left dorsolateral prefrontal cortex (DLPFC) highly heterogenous, and response rates may depend on precise location where in DLPFC rTMS administered. targeting approaches have ranged from a variety scalp measurement techniques, such as 5-cm rule or Beam F3 method, to neuroimaging neuronavigation. The Scalp Geometry-based Parameter (SGP) developed by Jiang colleagues (2022) provides potentially clinically useful approach manually individualized cortical locations without navigation systems. This method timely compared other techniques cost-effective applications. Methods: We modified (Beam, et al.,2009) with SGP values Cash al (2021) Optimal Group Target (Jiang al., 2022) 26 patients undergoing depression applying both methods measuring distance between them. Both took less than 2 minutes average complete, slightly shorter time SGP. To summarize measurements: 1) nasion inion was measured (Lnz). 2) S’ calculated multiplying step 1 constant 0.27 (Pnz) marked. 3) preauricular points (Lal), passing through s’. S marked at Lal multiplied 0.34 (Pal). our final point method. For more in-depth explanation this please refer 2022. Results: two measurements were very close together an 1.09 cm (standard deviation= 0.51) them, however, rendered anterior targets. Of participants, directly location, 11 anteromedial, 13 anterolateral. Conclusions: based previously established probabilistic mapping relates each position MNI space, individual MRI data. While small, participants. angle varied, being anterolateral participants anteromedial. Future studies larger sample sizes are needed accurately measure these points. At least previous found greater antidepressant effects (Cash 2019; Herbsman al. 2009). findings suggest be locating most depression, however further research needed. Conflicts Interest: None Funding: Disclosures: