REPETITIVE TRANSCRANIAL MAGNET STIMULATION AS A NEW TREATMENT CONCEPT FOR NEUROPATHIC PAIN IN SMALL FIBER NEUROPATHY

Chronic neuropathic pain is a hallmark symptom of Small Fiber Neuropathies (SFN). Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive neurostimulation technique established for the treatment of depression. We herein explore potential effects of rTMS on neuropathic pain, depressive symptoms, and quality of life in SFN patients.
In an ongoing monocentric, prospective, rater-blinded trial, up to 50 adult SFN patients are randomized into two different facilitating rTMS protocols. All participants receive 27 stimulations over a period of 18 weeks, consisting of a four-week treatment (20 sessions) followed by a maintenance phase. Protocol 1 stimulates at a frequency of 10 Hz for 15 minutes (3000 pulses), targeting the left primary motor cortex in the hand area (M1-rTMS). Protocol 2 uses intermittent theta-burst stimulation for three minutes (600 pulses) over the left dorsolateral prefrontal cortex (DLPFC-iTBS). To evaluate stimulation effects, neuropathic pain intensity, pain and sensory thresholds via Quantitative Sensory Testing (QST), and participants' mood will be assessed at weeks 0, 4, 18, and 21. We defined the primary endpoint as a reduction in pain by 20% compared to baseline.
Recruitment is ongoing. Currently, 15 patients have completed the study. At the time of the conference, we will present: 1) an innovative study concept, 2) the current status of recruitment, and 3) interim results.
97% of patients in our SFN registry report neuropathic pain as their primary symptom. Conceptually, rTMS addresses pain processing. Should one of our stimulation protocols prove effective, it could further support the therapeutic relevance of M1-rTMS or/and DLPFC-iTBS.