What Intensity of Deep Transcranial Magnetic Stimulation is Necessary to Remit Treatment Resistant Depression

Journal: Brain Stimulation (2018)

Authors: R Gersner, A Tendler, A Zangen, Y Roth,

Background:

dTMSfor treatment resistant depression uses high frequency pulses to stimulate the prefrontal cortex at an intensity of 120% of the resting motor threshold (120MT).

Objective:

Intensity and efficacy data from the active arm of the Brainswaymulticenter clinical trial were analyzed to determine whether 120MT is necessary to achieve remission or are lower intensities efficacious.

Methods:

101 active dTMS multicenter trial participants received 4 weeks of 5-a-week H1-coil dTMS. From treatment 3 and on subjects had to receive stimulation at 120% of MT. HDRS-21 scores up to week 5 and remission and response rtes at week 5 were compared between patients who received adequate and lower dTMS doses (a protocol deviation).

Results:

Twelve patients received an average intensity of <118MT (mean SD = 112.5% 4.0%) are considered the low dose (LD) group. Six of the LD patients had at least one HDRS-21 assessment. One reached response (1/6=16.7%) and none reached remission. Eighty-ninepatients received adequate treatment at >118MT and are considered the per protocol (PP) group. Eighty-six PP patients had at least one HDRS-21 assessment. Thirty-three reached response (33/86=38.4%) and twenty-eight reached remission (28/86=32.6%).

Conclusions:

dTMS below 118MT has low efficacy and is unlikely to result in remission. The deeper and broader stimulation induced at 120MT likely recruits many neural sites relevant for antidepressant response. Conclusions are limited by this being a post hoc analysis of protocol deviation.