Repetitive transcranial magnetic stimulation of the prefrontal cortex for fibromyalgia syndrome: a randomised controlled trial with 6-months follow up.

OBJECTIVES: Fibromyalgia Syndrome (FMS), is a chronic pain disorder with poorly understood pathophysiology. In recent years, repetitive transcranial magnetic stimulation (rTMS) has been recommended for pain relief in various chronic pain disorders. The objective of the present research was to study the effect of low frequency rTMS over the right dorsolateral prefrontal cortex (DLPFC) on pain status in FMS. METHODS: Ninety diagnosed cases of FMS were randomized into Sham-rTMS and Real-rTMS groups. Real rTMS (1 Hz/1200 pulses/8 trains/90% resting motor threshold) was delivered over the right DLPFC for 5 consecutive days/week for 4 weeks. Pain was assessed by subjective and objective methods along with oxidative stress markers. Patients were followed up for 6 months (post-rTMS;15 days, 3 months and 6 months). RESULTS: In Real-rTMS group, average pain ratings and associated symptoms showed significant improvement post rTMS. The beneficial effects of rTMS lasted up to 6 months in the follow-up phase. In Sham-rTMS group, no significant change in pain ratings was observed. CONCLUSION: Right DLPFC rTMS can significantly reduce pain and associated symptoms of FMS probably through targeting spinal pain circuits and top-down pain modulation . TRIAL REGISTRATION: Ref No: CTRI/2013/12/004228.

Repetitive transcranial magnetic stimulation of the prefrontal cortex for fibromyalgia syndrome: a randomised controlled trial with 6-months follow up

Abstract Objectives Fibromyalgia Syndrome (FMS), is a chronic pain disorder with poorly understood pathophysiology. In recent years, repetitive transcranial magnetic stimulation (rTMS) has been recommended for pain relief in various chronic pain disorders. The objective of the present research was to study the effect of low frequency rTMS over the right dorsolateral prefrontal cortex (DLPFC) on pain status in FMS. Methods Ninety diagnosed cases of FMS were randomized into Sham-rTMS and Real-rTMS groups. Real rTMS (1 Hz/1200 pulses/8 trains/90% resting motor threshold) was delivered over the right DLPFC for 5 consecutive days/week for 4 weeks. Pain was assessed by subjective and objective methods along with oxidative stress markers. Patients were followed up for 6 months (post-rTMS;15 days, 3 months and 6 months). Results In Real-rTMS group, average pain ratings and associated symptoms showed significant improvement post rTMS. The beneficial effects of rTMS lasted up to 6 months in the follow-up phase. In Sham-rTMS group, no significant change in pain ratings was observed. Conclusion Right DLPFC rTMS can significantly reduce pain and associated symptoms of FMS probably through targeting spinal pain circuits and top-down pain modulation . Trial registration: Ref No: CTRI/2013/12/004228.(AU)

Repetitive transcranial magnetic stimulation in chronic tension-type headache: A pilot study.

Background & objectives: Tension-type headache (TTH) is the most common type of primary headache disorder. Its chronic form is often the most ignored and challenging to treat. Transcranial magnetic stimulation (TMS) is a novel technique in the treatment of chronic pain. The aim of this pilot study was to explore the effect of low-frequency repetitive TMS (rTMS) on pain status in chronic TTH (CTTH) by subjective and objective pain assessment. Methods: Patients (n=30) diagnosed with CTTH were randomized into rTMS (n=15) and placebo (n=15) groups in this study. Pre-intervention detailed history of patients was taken. Numerical Rating Scale (NRS) for Pain and questionnaires [Headache Impact Test-6 (HIT-6), McGill Pain Questionnaire, Pain Beliefs Questionnaire, Coping Strategies Questionnaire, State-Trait Anxiety Inventory Test, Hamilton Rating Scale for Depression and WHO-Quality of Life Questionnaire-Brief version] were filled, and objective assessments such as nociceptive flexion reflex (NFR) and conditioned pain modulation were done. The tests were repeated after 20 sessions (5 days/week). In the rTMS group, 1200 pulses in eight trains of 150 pulses each were given at 1Hz over the right dorsolateral prefrontal cortex (RDLPFC). In the placebo group, the rTMS coil was placed such that magnetic stimulation did not reach the cortex. Results: The NRS score decreased significantly (P<0.001) and NFR thresholds increased significantly (P=0.011) in the rTMS group when compared to placebo group. Interpretation & conclusions: Subjective improvements in the NRS, HIT-6, McGill Present Pain Intensity, trait of anxiety and psychological pain beliefs were observed. The increase in the thresholds of NFR served as an objective marker for improvement in pain status. Further studies need to be done to confirm our preliminary findings.

Can aberrant spinal nociception be a marker of chronicity of pain in fibromyalgia syndrome?

Pain sensitivity is a recognized feature of fibromyalgia syndrome (FMS) but the contribution of spinal nociceptive circuitry to this phenomenon is unknown. Therefore, the objectives were to study the changes in spinal nociception i.e. nociceptive flexion reflex (NFR) in patients with FMS and to investigate correlation if any, between NFR threshold, pain duration and tender points in FMS. One hundred and three patients with FMS and 74 healthy volunteers participated in the study. To record NFR, sural nerve was stimulated in the retro malleolar region and the reflex response was recorded from the short head of biceps femoris muscle. NFR was elicited at significantly lower [21.0(18.0-25.0)V] thresholds in FMS group when compared to healthy subjects [30.0(24.75-35.0)V; p = 0.001] indicating hyperalgesic response to electrocutaneous stimulation in FMS patients. The latency and other parameters of NFR were comparable in both the groups. No significant correlation was found among NFR threshold and pain duration or tender points. On the basis of results of present study, it may be concluded that the functional deficit of the spinal nociceptive system can contribute to hyperalgesia in FMS. This is first study that correlates a marker of central hyper-excitability (NFR threshold) with clinical symptoms (pain duration and tender points) of FMS.