Electrophysiological Biomarkers of Treatment Response in Major Depressive Disorder Patients Receiving Accelerated Transcranial Magnetic Stimulation

This study investigates whether physiological signals recorded during transcranial magnetic stimulation (TMS) can predict which patients with major depression respond to treatment. Thirty-two adults with major depressive disorder receive an accelerated TMS protocol targeting the dorsomedial prefrontal cortex using a double-cone coil, delivered as four sessions per day over five to eight days. Heart rate is continuously monitored throughout every stimulation session using a chest-strap sensor, and electroencephalography (EEG) is recorded before and after treatment. Heart-brain coupling was assessed in a separate dedicated session after the target stimulation dose was reached.The primary clinical outcome is the change in depression severity measured by the Hamilton Depression Rating Scale (HAMD-17) from baseline to post-treatment. Prespecified physiological outcomes include stimulation-evoked heart rate deceleration, resting-state EEG parameters, and heart-brain coupling metrics. The aim is to evaluate whether these electrophysiological measures index target engagement and predict antidepressant response, potentially supporting their use as functional biomarkers for personalizing accelerated TMS in depression.