Background: Repetitive transcranial magnetic stimulation (rTMS) has shown promise in the alleviation of acute and\r\nchronic pain by altering the activity of cortical areas involved in pain sensation. However, current single-coil rTMS\r\ntechnology only allows for effects in surface cortical structures. The ability to affect activity in certain deep brain\r\nstructures may however, allow for a better efficacy, safety, and tolerability. This study used PET imaging to\r\ndetermine whether a novel multi-coil rTMS would allow for preferential targeting of the dorsal anterior cingulate\r\ncortex (dACC), an area always activated with pain, and to provide preliminary evidence as to whether this targeted\r\napproach would allow for efficacious, safe, and tolerable analgesia both in a volunteer/acute pain model as well as\r\nin fibromyalgia chronic pain patients.\r\nMethods: Part 1: Different coil configurations were tested in a placebo-controlled crossover design in volunteers\r\n(N = 16). Tonic pain was induced using a capsaicin/thermal pain model and functional brain imaging was performed\r\nby means of H2\r\n15O positron emission tomography ââ?¬â?? computed tomography (PET/CT) scans. Differences in NRS pain\r\nratings between TMS and sham treatment (NRSTMS-NRSplacebo) which were recorded each minute during the\r\n10 minute PET scans. Part 2: 16 fibromyalgia patients were subjected to 20 multi-coil rTMS treatments over 4 weeks\r\nand effects on standard pain scales (Brief Pain Inventory, item 5, i.e. average pain NRS over the last 24 hours) were\r\nrecorded.\r\nResults: A single 30 minute session using one of 3 tested rTMS coil configurations operated at 1 Hz consistently\r\nproduced robust reduction (mean 70% on NRS scale) in evoked pain in volunteers. In fibromyalgia patients, the 20\r\nrTMS sessions also produced a significant pain inhibition (43% reduction in NRS pain over last 24 hours), but only when\r\noperated at 10 Hz. This degree of pain control was maintained for at least 4 weeks after the final session.\r\nConclusion: Multi-coil rTMS may be a safe and effective treatment option for acute as well as for chronic pain, such as\r\nthat accompanying fibromyalgia. Further studies are necessary to optimize configurations and settings as well as to\r\nelucidate the mechanisms that lead to the long-lasting pain control produced by these treatments.
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