Efficacy and Safety of Low-field Synchronized Transcranial Magnetic Stimulation (sTMS) for Treatment of Major Depression

Brain Stimul. 2015 Jul-Aug;8(4):787-94. doi: 10.1016/j.brs.2015.05.005. Epub 2015 May 22.


Background: Transcranial Magnetic Stimulation (TMS) customarily uses high-field electromagnets to achieve therapeutic efficacy in Major Depressive Disorder (MDD). Low-field magnetic stimulation also may be useful for treatment of MDD, with fewer treatment-emergent adverse events.

Objective/hypothesis: To examine efficacy, safety, and tolerability of low-field magnetic stimulation synchronized to an individual's alpha frequency (IAF) (synchronized TMS, or sTMS) for treatment of MDD.

Methods: Six-week double-blind sham-controlled treatment trial of a novel device that used three rotating neodymium magnets to deliver sTMS treatment. IAF was determined from a single-channel EEG prior to first treatment. Subjects had baseline 17-item Hamilton Depression Rating Scale (HamD17) ≥ 17.

Results: 202 subjects comprised the intent-to-treat (ITT) sample, and 120 subjects completed treatment per-protocol (PP). There was no difference in efficacy between active and sham in the ITT sample. Subjects in the PP sample (N = 59), however, had significantly greater mean decrease in HamD17 than sham (N = 60) (-9.00 vs. -6.56, P = 0.033). PP subjects with a history of poor response or intolerance to medication showed greater improvement with sTMS than did treatment-naïve subjects (-8.58 vs. -4.25, P = 0.017). Efficacy in the PP sample reflects exclusion of subjects who received fewer than 80% of scheduled treatments or were inadvertently treated at the incorrect IAF; these subgroups failed to separate from sham. There was no difference in adverse events between sTMS and sham, and no serious adverse events attributable to sTMS.

Conclusions: Results suggest that sTMS may be effective, safe, and well tolerated for treating MDD when administered as intended.

Keywords: Alpha oscillations; Clinical treatment trial; Electroencephalogram (EEG); Individual Alpha Frequency (IAF); Low-intensity magnetic field; Major Depressive Disorder; Neuromodulation; Oscillatory synchrony; Static magnet; Synchronized Transcranial Magnetic Stimulation (sTMS).

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Depressive Disorder, Major / therapy*
  • Double-Blind Method
  • Female
  • Humans
  • Male
  • Middle Aged
  • Psychiatric Status Rating Scales
  • Transcranial Magnetic Stimulation / adverse effects
  • Transcranial Magnetic Stimulation / methods*
  • Treatment Outcome