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Crossover to Bilateral Repetitive Transcranial Magnetic Stimulation

A Potential Strategy When Patients Are Not Responding to Unilateral Left-Sided High-Frequency Repetitive Transcranial Magnetic Stimulation

Cristancho, Pilar, MD*; Trapp, Nicholas T., MD; Siddiqi, Shan H., MD*‡; Dixon, David, PhD*; Miller, J. Philip, AB§; Lenze, Eric J., MD*

doi: 10.1097/YCT.0000000000000500

Clinical trials using left-sided repetitive transcranial magnetic stimulation (rTMS) report remission rates of 14% to 32.6%. A large percentage of patients would not achieve remission with standard rTMS treatment. The question of what clinicians should do when a patient is not responding to standard high-frequency (HF) left-sided rTMS remains unanswered. This prospective case series examines whether crossover to bilateral stimulation enhances antidepressant outcomes in patients not responding to unilateral rTMS. Patients in a major depressive episode received an rTMS clinical protocol of 4 to 6 weeks' duration. Stimulation began with HF rTMS (10 Hz) over the left dorsolateral prefrontal cortex (range, 3000–5000 pulses per session). A total of 17 patients without sufficient clinical improvement early in their rTMS course received 1-Hz rTMS (range, 600–1200 pps) over the right dorsolateral prefrontal cortex (added to the HF left-sided stimulation). Hamilton Depression Rating Scale scores decreased from 13.9 ± 3.9 (mean ± SD) from the start of augmentation to 12.2 ± 5.8 at the end of acute treatment, a 1.7-point change, Cohen d effect size = −0.35, 95% confidence interval, −1.01 to − 0.34, suggesting improvement. Remission rate in this sample was 24% (4/17). This case series indicates that crossover to bilateral stimulation is a feasible and potentially effective strategy when patients are not improving with standard rTMS. A randomized controlled trial comparing crossover versus standard rTMS is needed to determine the efficacy of this paradigm.

From the *Department of Psychiatry, Healthy Mind Lab, School of Medicine, Washington University in St Louis, St Louis, MO;

University of Iowa Hospital and Clinics, Iowa City, IA;

Department of Neurology, McLean Hospital and Harvard Medical School, Boston, MA; and

§Division of Biostatistics, School of Medicine, Washington University in St Louis, St Louis, MO.

Received for publication November 10, 2017; accepted February 20, 2018.

Reprints: Pilar Cristancho, MD, Washington University School of Medicine in St Louis, St Louis, Campus Box 8134, 660 S Euclid Ave, St Louis, MO 63110 (e-mail:

Research reported in this publication was supported by the National Institute of Mental Health grants 3R34MH101433 to Washington University, The Center for Brain Research in Mood Disorders at Washington University, and The Foundation for Barnes-Jewish Hospital.

The authors have no conflicts of interest to disclose.

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