Research & Evidence

1. Why Coil Position Matters. Where the TMS coil sits matters. Scalp-based rules such as standard Beam F3 position the coil from basic tape measurements and cannot fully account for individual cranial anatomy. MRI-guided optical neuronavigation is more precise, but many clinics do not have it on site, and it adds registration time to every session.

2. Cranial Morphology & Cephalic Index (Mir-Moghtadaei et al., 2015; Li et al., 2025). Standard scalp heuristics approximate the cranium as a sphere, which introduces systematic localization error on elongated dolichocephalic (CI < 75) or wide brachycephalic (CI > 80) skulls:
CI = (Cranial Biparietal Width / Cranial Anteroposterior Length) × 100
Our free TargetStudio™ Beam F3 Pro Calculator provides anthropometric Cephalic Index compensation and normative P5–P95 head percentiles, while our 3D-printed interfaces register directly to the individual's 3D head surface.

3. Stokes Cortical Depth Intensity Adjustment (Stokes et al., 2007). When the prefrontal target (DLPFC) lies deeper from the scalp than the primary motor cortex hand knob (M1), nominal RMT stimulation can under-dose the target cortex. Scaling stimulator output by scalp-to-cortex distance differential accounts for depth-dependent field decay:
Target Intensity = RMT × [ 1 + 0.027 × (Distance_DLPFC − Distance_M1) ]

4. 3D-Printed Headsets & Ongoing Validation (Mansouri et al., 2018; Patent AT 527771). Patient-specific, 3D-printed headsets were proposed and validated in a 2018 study by Mansouri et al. (Journal of Neural Engineering, doi:10.1088/1741-2552/aacb96) as a practical way to reproduce a planned coil pose without daily camera tracking. Brainautics is preparing a formal validation study measuring how precisely its patented interfaces (AT 527771) reproduce coil position across repeated placement compared with optical neuronavigation (with a 0.5 mm mechanical design target). We will publish the measured results on this page; until then, we make no clinical accuracy or treatment outcome claims. Brainautics interfaces are supplied for research use and are not CE-marked or FDA-cleared.