A Pilot Study Investigating the Effects of Fast Left Prefrontal rTMS on Chronic Neuropathic Pain

Abstract

Objective Stimulating the human cortex using transcranial magnetic stimulation (TMS) temporarily reduces clinical and experimental pain, however, it is unclear which cortical targets are the most effective. The motor cortex has been a popular target for managing neuropathic pain, while the prefrontal cortex has been investigated for an array of nociceptive pain conditions. It is unclear whether the motor cortex is the only effective cortical target for managing neuropathic pain, and no published studies to date have investigated the effects of prefrontal stimulation on neuropathic pain. Design This preliminary pilot trial employed a sham-controlled, within-subject, cross-over design to evaluate clinical pain as well as laboratory pain thresholds among four patients with chronic neuropathic pain. Each participant underwent three real and three sham 20-minute sessions of 10Hz left prefrontal rTMS. Daily pain diaries were collected for 3-weeks before and after each treatment phase along with a battery of self-report pain and mood questionnaires. Results Time-series analysis at the individual patient level indicated that real TMS was associated with significant improvements in average daily pain in 3 of the 4 participants. These effects were independent of changes in mood in 2 of the participants. At the group level, a decrease of 19% in daily pain on average, pain at its worst, and pain at its least was observed while controlling for changes in mood, activity-level and sleep. The effects of real TMS were significantly greater than sham. Real TMS was associated with increases in thermal and mechanical pain thresholds whereas sham was not. No statistically significant effects were observed across the questionnaire data. Conclusions The prefrontal cortex may be an important TMS cortical target for managing certain types of pain, including certain neuropathic pain syndromes.

Feasibility, safety, and effectiveness of transcranial direct current stimulation for decreasing post-ERCP pain: a randomized, sham-controlled, pilot study

“…24,27 The present study is the first to our knowledge to show that tDCS may be able to produce analgesic effects similar to that of those studies and the first to use either type of brain stimulation to decrease periprocedural pain in endoscopy. The optimal cortical targets for stimulation are not wellestablished.…”

“…24,27 The same may not necessarily hold true for tDCS. It is possible that mood-modulating effects of prefrontal tDCS in the present study drive changes in pain appraisal and pain behaviors that confound our results.…”

“…9,11,14-21 TMS over the prefrontal cortex has been shown to affect pain perception in neuropathic pain, experimentally induced pain, fibromyalgia, and postoperative pain. 22,[23][24][25][26][27] In fact, high frequency TMS for 20 minutes after gastric bypass surgery was associated with approximately 40% less patient-controlled analgesia use than controls over the subsequent 48 hours, with less pain. 23,26 TMS is more complicated to deliver, has more adverse events than tDCS, and is more cumbersome in the postoperative setting.…”

Transcranial Direct Current Stimulation Targeting Primary Motor Versus Dorsolateral Prefrontal Cortices: Proof-of-Concept Study Investigating Functional Connectivity of Thalamocortical Networks Specific to Sensory-Affective Information Processing

“…Nociceptive cutaneous heat stimuli were applied using a TSA-II Neurosensory Analyzer (Medoc, Durham, NC) using a 3 · 3 cm thermode on the volar aspect of distal left forearm. The apparatus is MRI compatible and is frequently used in several pain studies and is seldom associated with adverse events (Borckardt et al, 2009). For thresholding, the participants' skin was permitted to adapt to a temperature of 32°C for some time.…”

Daily left prefrontal repetitive transcranial magnetic stimulation for medication-resistant burning mouth syndrome

“…Recent studies have found beneficial effects of TMS for acute and chronic pain. 4,5 In terms of chronic orofacial pain, there are many subtypes, and some argue that the subtypes differ substantially. 6 Although some studies have shown the efficacy of daily fast rTMS for orofacial pain including atypical facial pain, dental pain, and neuralgia, 4,5 there appear to be no reports on the efficacy of rTMS for BMS.…”