H-coil repetitive transcranial magnetic stimulation for the treatment of bipolar depression: an add-on, safety and feasibility study.

OBJECTIVES: The H1-Coil is a novel transcranial magnetic stimulation (TMS) device capable of inducing a magnetic field with a deeper and wider distribution than standard coils. This pilot study evaluated the safety and feasibility of the H1-Coil as adjuvant treatment for bipolar depression (BPD). METHODS: Nineteen patients diagnosed as having BPD and under treatment with psychotropic medication were enrolled in the study. They received daily prefrontal repetitive TMS (rTMS: 20 Hz, 2 s on, 20 s off, totaling 1680 stimuli) every weekday for four consecutive weeks. The primary outcome measure was the change from baseline in the Hamilton Depression Rating Scale (HDRS-24) score a week after the last treatment session. RESULTS: A significant mean decrease of 12.9 points in the HDRS-24 scale (P< 0.001) was found. Response rate was 63.2% and remission rate was 52.6%. Treatment was well tolerated in terms of headache and overall discomfort, and there were no significant change in cognitive functioning or mood switches. One patient had a short induced generalized seizure without complications. CONCLUSIONS: An add-on H-coil rTMS treatment protocol in BPD subjects indicated improvement in bipolar depression symptoms. Sham-control studies to further determine the efficacy and safety of the H-Coil for BPD are warranted.