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Shaped magnetic field pulses by multi-coil repetitive transcranial magnetic stimulation (rTMS) differentially modulate anterior cingulate cortex responses and pain in volunteers and fibromyalgia patients.

Tzabazis A, Aparici CM, Rowbotham MC, Schneider MB, Etkin A, Yeomans DC - Mol Pain (2013)

Bottom Line: The ability to affect activity in certain deep brain structures may however, allow for a better efficacy, safety, and tolerability.A single 30 minute session using one of 3 tested rTMS coil configurations operated at 1 Hz consistently produced robust reduction (mean 70% on NRS scale) in evoked pain in volunteers.In fibromyalgia patients, the 20 rTMS sessions also produced a significant pain inhibition (43% reduction in NRS pain over last 24 hours), but only when operated at 10 Hz.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Repetitive transcranial magnetic stimulation (rTMS) has shown promise in the alleviation of acute and chronic pain by altering the activity of cortical areas involved in pain sensation. However, current single-coil rTMS technology only allows for effects in surface cortical structures. The ability to affect activity in certain deep brain structures may however, allow for a better efficacy, safety, and tolerability. This study used PET imaging to determine whether a novel multi-coil rTMS would allow for preferential targeting of the dorsal anterior cingulate cortex (dACC), an area always activated with pain, and to provide preliminary evidence as to whether this targeted approach would allow for efficacious, safe, and tolerable analgesia both in a volunteer/acute pain model as well as in fibromyalgia chronic pain patients.

Methods: Part 1: Different coil configurations were tested in a placebo-controlled crossover design in volunteers (N = 16). Tonic pain was induced using a capsaicin/thermal pain model and functional brain imaging was performed by means of H2(15)O positron emission tomography - computed tomography (PET/CT) scans. Differences in NRS pain ratings between TMS and sham treatment (NRS(TMS)-NRS(placebo)) which were recorded each minute during the 10 minute PET scans. Part 2: 16 fibromyalgia patients were subjected to 20 multi-coil rTMS treatments over 4 weeks and effects on standard pain scales (Brief Pain Inventory, item 5, i.e. average pain NRS over the last 24 hours) were recorded.

Results: A single 30 minute session using one of 3 tested rTMS coil configurations operated at 1 Hz consistently produced robust reduction (mean 70% on NRS scale) in evoked pain in volunteers. In fibromyalgia patients, the 20 rTMS sessions also produced a significant pain inhibition (43% reduction in NRS pain over last 24 hours), but only when operated at 10 Hz. This degree of pain control was maintained for at least 4 weeks after the final session.

Conclusion: Multi-coil rTMS may be a safe and effective treatment option for acute as well as for chronic pain, such as that accompanying fibromyalgia. Further studies are necessary to optimize configurations and settings as well as to elucidate the mechanisms that lead to the long-lasting pain control produced by these treatments.

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Related in: MedlinePlus

Ratio of deep vs. superficial PET ROI activity changes (real treatment – sham treatment). Configurations A and B lead to a marked decrease, whereas configuration C lead to a small increase in activity ratio. *: indicated p < 0.05 (one way ANOVA).
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Figure 2: Ratio of deep vs. superficial PET ROI activity changes (real treatment – sham treatment). Configurations A and B lead to a marked decrease, whereas configuration C lead to a small increase in activity ratio. *: indicated p < 0.05 (one way ANOVA).

Mentions: When calculating the activity ratios for average PET activity in the deep (posterior dorsal ACC, anterior dorsal ACC, and the pregenual ACC) versus superficial (supplementary motor area (SMA), preSMA, dorsomedial PFC, and rostromedial PFC) regions of interest in each volunteer, configuration B lead to the biggest decrease in PET activity ratio changes (Figure 2). Consistent with this finding is the observation of the significant analgesic effect after real multi-coil rTMS with configuration B. Interestingly, these changes in PET activity ratio were mostly explained by the almost absent change in activation in the superficial brain areas, -0.04 and 0.125 for configuration A and B, respectively. This indicates that the multi-coil rTMS causes its effect by modulating deep rather than superficial brain structures. Correlating the PET activity ratio with the averaged change in NRS pain ratings during the first 2 minutes (the time period over which H215O PET is most sensitive due to the rapid decay) yielded a significant correlation coefficient of 0.61.


Shaped magnetic field pulses by multi-coil repetitive transcranial magnetic stimulation (rTMS) differentially modulate anterior cingulate cortex responses and pain in volunteers and fibromyalgia patients.

Tzabazis A, Aparici CM, Rowbotham MC, Schneider MB, Etkin A, Yeomans DC - Mol Pain (2013)

Ratio of deep vs. superficial PET ROI activity changes (real treatment – sham treatment). Configurations A and B lead to a marked decrease, whereas configuration C lead to a small increase in activity ratio. *: indicated p < 0.05 (one way ANOVA).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3750766&req=5

Figure 2: Ratio of deep vs. superficial PET ROI activity changes (real treatment – sham treatment). Configurations A and B lead to a marked decrease, whereas configuration C lead to a small increase in activity ratio. *: indicated p < 0.05 (one way ANOVA).
Mentions: When calculating the activity ratios for average PET activity in the deep (posterior dorsal ACC, anterior dorsal ACC, and the pregenual ACC) versus superficial (supplementary motor area (SMA), preSMA, dorsomedial PFC, and rostromedial PFC) regions of interest in each volunteer, configuration B lead to the biggest decrease in PET activity ratio changes (Figure 2). Consistent with this finding is the observation of the significant analgesic effect after real multi-coil rTMS with configuration B. Interestingly, these changes in PET activity ratio were mostly explained by the almost absent change in activation in the superficial brain areas, -0.04 and 0.125 for configuration A and B, respectively. This indicates that the multi-coil rTMS causes its effect by modulating deep rather than superficial brain structures. Correlating the PET activity ratio with the averaged change in NRS pain ratings during the first 2 minutes (the time period over which H215O PET is most sensitive due to the rapid decay) yielded a significant correlation coefficient of 0.61.

Bottom Line: The ability to affect activity in certain deep brain structures may however, allow for a better efficacy, safety, and tolerability.A single 30 minute session using one of 3 tested rTMS coil configurations operated at 1 Hz consistently produced robust reduction (mean 70% on NRS scale) in evoked pain in volunteers.In fibromyalgia patients, the 20 rTMS sessions also produced a significant pain inhibition (43% reduction in NRS pain over last 24 hours), but only when operated at 10 Hz.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Repetitive transcranial magnetic stimulation (rTMS) has shown promise in the alleviation of acute and chronic pain by altering the activity of cortical areas involved in pain sensation. However, current single-coil rTMS technology only allows for effects in surface cortical structures. The ability to affect activity in certain deep brain structures may however, allow for a better efficacy, safety, and tolerability. This study used PET imaging to determine whether a novel multi-coil rTMS would allow for preferential targeting of the dorsal anterior cingulate cortex (dACC), an area always activated with pain, and to provide preliminary evidence as to whether this targeted approach would allow for efficacious, safe, and tolerable analgesia both in a volunteer/acute pain model as well as in fibromyalgia chronic pain patients.

Methods: Part 1: Different coil configurations were tested in a placebo-controlled crossover design in volunteers (N = 16). Tonic pain was induced using a capsaicin/thermal pain model and functional brain imaging was performed by means of H2(15)O positron emission tomography - computed tomography (PET/CT) scans. Differences in NRS pain ratings between TMS and sham treatment (NRS(TMS)-NRS(placebo)) which were recorded each minute during the 10 minute PET scans. Part 2: 16 fibromyalgia patients were subjected to 20 multi-coil rTMS treatments over 4 weeks and effects on standard pain scales (Brief Pain Inventory, item 5, i.e. average pain NRS over the last 24 hours) were recorded.

Results: A single 30 minute session using one of 3 tested rTMS coil configurations operated at 1 Hz consistently produced robust reduction (mean 70% on NRS scale) in evoked pain in volunteers. In fibromyalgia patients, the 20 rTMS sessions also produced a significant pain inhibition (43% reduction in NRS pain over last 24 hours), but only when operated at 10 Hz. This degree of pain control was maintained for at least 4 weeks after the final session.

Conclusion: Multi-coil rTMS may be a safe and effective treatment option for acute as well as for chronic pain, such as that accompanying fibromyalgia. Further studies are necessary to optimize configurations and settings as well as to elucidate the mechanisms that lead to the long-lasting pain control produced by these treatments.

Show MeSH
Related in: MedlinePlus