More recent work with a related EEG-based measure, the Antidepressant Treatment Response Index (ATR) has led to a simplified monitoring system; a physician can record clinically-useful data from a 15-minute in-office procedure with electrodes located on the forehead and ears (Leuchter et al., in submission). The ATR uses physiologic data collected prior to treatment and after one week of exposure, and was shown to be predictive of outcome with antidepressant medication. We are able to assess both cordance and ATR measures with EEG measurements made prior to treatment and after 5 treatment sessions with TMS to evaluate the predictive properties of both metrics.