Herbsman et al. (2009) used fMRI to assess DLPFC localisation accuracy across 17 healthy volunteers. The 5cm rule correctly identified the DLPFC in only 4 of 17 participants. The mean error was 18mm — clinically significant given that rTMS stimulation volumes at standard intensities extend only 2–3cm from the coil.

A subsequent study (Fitzgerald et al., 2009) found that neuronavigated coil placement was associated with significantly greater antidepressant response compared to the 5cm rule, even when controlling for intensity and session number. The mechanism is straightforward: if you’re not stimulating the DLPFC, you’re not getting the intended therapeutic effect.

At BrainAid Clinics, every patient receives an individualised brain map from their structural MRI before treatment commences. Coil position is tracked in real time throughout every ~10 days using neuronavigation software, and coordinates are logged for reproducibility across the full course.

Herbsman et al. (2009) Hum Brain Mapp; Fitzgerald et al. (2009) Brain Stimul