The Utility of Concurrent TBS/fNIRS for Antidepressant Treatment Optimization

TBS comprises 3-pulse 50-Hz bursts, applied every 200 ms (at 5 Hz) as described previously (Huang, Edwards et al. 2005). iTBS consists of 2-second trains with an inter-train-interval of 8 seconds. We will repeat trains (30 pulses; 10 bursts) for 20 times to reach a total number of 600 pulses (3x10x20). cTBS will comprise uninterrupted bursts to reach a total number of 600 pulses, as done routinely by others. Concurrent TBS/fNIRS stimulation will be applied over the left (iTBS) and right (cTBS) DLPFC at an intensity of 70-120%\* resting motor threshold (RMT) (The ideal %RMT will be determined first in a pilot study). In part two, stimulation intensity for patients will be 120% RMT (titration to full therapeutic dose over the first three days), as approved by the FDA in the U.S. (Blumbeger et al. 2018). The stimulation site will be the same as in the concurrent TBS/fNIRS stimulation (see above).