Effects of unilateral repetitive transcranial magnetic stimulation of the motor cortex on chronic widespread pain in fibromyalgia

Abstract

Non-invasive unilateral repetitive transcranial magnetic stimulation (rTMS) of the motor cortex induces analgesic effects in focal chronic pain syndromes, probably by modifying central pain modulatory systems. Neuroimaging studies have shown bilateral activation of a large number of structures, including some of those involved in pain processing, suggesting that such stimulation may induce generalized analgesic effects. The goal of this study was to assess the effects of unilateral rTMS of the motor cortex on chronic widespread pain in patients with fibromyalgia. Thirty patients with fibromyalgia syndrome (age: 52.6 +/- 7.9) were randomly assigned, in a double-blind fashion, to two groups, one receiving active rTMS (n = 15) and the other sham stimulation (n = 15), applied to the left primary motor cortex in 10 daily sessions. The primary outcome measure was self-reported average pain intensity over the last 24 h, measured at baseline, daily during the stimulation period and then 15, 30 and 60 days after the first stimulation. Other outcome measures included: sensory and affective pain scores for the McGill pain Questionnaire, quality of life (assessed with the pain interference items of the Brief Pain Inventory and the Fibromyalgia Impact Questionnaire), mood and anxiety (assessed with the Hamilton Depression Rating Scale, the Beck Depression Inventory and the Hospital Anxiety and Depression Scale). We also assessed the effects of rTMS on the pressure pain threshold at tender points ipsi- and contralateral to stimulation. Follow-up data were obtained for all the patients on days 15 and 30 and for 26 patients (13 in each treatment group) on day 60. Active rTMS significantly reduced pain and improved several aspects of quality of life (including fatigue, morning tiredness, general activity, walking and sleep) for up to 2 weeks after treatment had ended. The analgesic effects were observed from the fifth stimulation onwards and were not related to changes in mood or anxiety. The effects of rTMS were more long-lasting for affective than for sensory pain, suggesting differential effects on brain structures involved in pain perception. Only few minor and transient side effects were reported during the stimulation period. Our data indicate that unilateral rTMS of the motor cortex induces a long-lasting decrease in chronic widespread pain and may therefore constitute an effective alternative analgesic treatment for fibromyalgia.

Is the Transcranial Magnetic Stimulation an Adjunctive Treatment in Fibromyalgia Patients?

“…We therefore hypothesized that LF-rTMS of the motor cortex can reduce chronic widespread pain in patients with fibromyalgia, according to knowledge from previous studies. This hypothesis is supported by recent reports that non-invasive direct transcranial current stimulation of the motor cortex has analgesic effects in fibromyalgia patients (12,25). In the previous studies of Passard (25), Lefaucher (26,27), Mhalla (28), André-Obadia (29), and Nahmias (30), HF-rTMS was used, and analgesic effects of high-frequency stimulation of primary motor cortex were demonstrated.…”

“…Therefore, we thought that it can also be used as an adjunctive treatment in FM. This hypothesis was supported by a few studies that reported that non-invasive direct transcranial current stimulation and high-frequency (HF) rTMS of the motor cortex have analgesic effects in fibromyalgia patients (11,12).…”

Cerebral cortex modulation of pain

“…Based on these results, it is postulated that MCS may act through at least two mechanisms: activation of perigenual cingulate and orbitofrontal areas may modulate the emotional appraisal of pain, rather than its intensity; and top-down activation of brainstem PAG may lead to descending inhibition toward the spinal cord ( Figure 1). In addition, it was found that the effects of rTMS in the motor cortex are more long-lasting for affective than for sensory pain [100] . Active rTMS significantly reduced pain and improved several aspects of quality of life (including fatigue, morning tiredness, general activity, walking and sleep) for up to 2 weeks after treatment had ended [100] .…”

Imaging human brain networks to improve the clinical efficacy of non-invasive brain stimulation

“…This has led to a dramatic increase in research applying NIBS in the clinical domain, with the goal of improving abnormal brain function in various conditions (Hummel et al, 2005;Hummel and Cohen, 2006;Passard et al, 2007;Floel, 2014;Liew et al, 2014). The rationale for the use of NIBS has been that if behavioral changes arising from a clinical condition occur due to altered activity within a given brain network, normalizing this activity with NIBS should lead to improved behavior.…”