aiTBS and rTMS in Neuropathic Pain and Prediction of Response

This study evaluates the analgesic benefit of two non-invasive brain stimulation techniques: high frequency repetitive transcranial magnetic stimulation (rTMS) and accelerated intermittent theta burst stimulation (aiTBS) - compared to sham stimulation, in patients with chronic neuropathic pain lasting at least 6 months.

Transcranial magnetic stimulation, which is delivered by a coil positioned on the scalp over the motor cortex, generates a low-intensity, submotor-threshold electromagnetic field that noninvasively activates targeted brain regions involved in pain perception. The procedure is painless and non-invasive. Sham stimulation uses the inactive face of the same coil and produces an identical sound, ensuring that neither patients nor investigators know which stimulation is being delivered.

Conventional rTMS has demonstrated moderate analgesic efficacy in neuropathic pain, but its effect is delayed and requires at least 5 treatment sessions. iTBS delivers the same total stimulation dose in a much shorter time (approximately 8 minutes per session versus 30 minutes for conventional rTMS) and enables accelerated protocols with multiple sessions per day, which have shown promising results in depression.

This study compares aiTBS, rTMS and sham by a randomized controlled trial (RCT) with a crossover design: participants are randomized in a 2:1 ratio to receive either active stimulation (both techniques in sequence) or sham stimulation (both techniques in sequence). Each treatment phase consists of either 5 consecutive daily rTMS sessions or 5 aiTBS sessions delivered on a single day (with a 45-min pause between sessions). The cross-over will take place after a 4 to 6-week washout period between the two active or sham treatments. The total study duration per participant is from 10 to 12 weeks, with 11-12 in-person visits.

Assessments include self-reported pain diaries numeric pain rating scale (NPRS), validated pain, psychosocial, and quality-of-life questionnaires, resting-state Electroencephalography (EEG) recordings, and transcranial magnetic stimulation (TMS) based measures of intracortical excitability and inhibition. The exploratory aim is to identify neurophysiological and clinical predictors of treatment response, to better personalize the treatment in chronic pain population.