The effect of a series of repetitive transcranial magnetic stimulations of the motor cortex on central pain after spinal cord injury. Transcranial magnetic stimulation for pain control. Double-blind study of different frequencies against placebo, and correlation with motor cortex stimulation efficacy. Effects of unilateral repetitive transcranial magnetic stimulation of the motor cortex on chronic widespread pain in fibromyalgia. Motor cortex rTMS in chronic neuropathic pain: pain relief is associated with thermal sensory perception improvement. Interventional neurophysiology for pain control: duration of pain relief following repetitive transcranial magnetic stimulation of the motor cortex. Pain relief induced by repetitive transcranial magnetic stimulation of precentral cortex. A sham-controlled, phase II trial of transcranial direct current stimulation for the treatment of central pain in traumatic spinal cord injury. Repetitive transcranial magnetic stimulation of the motor cortex attenuates pain perception in complex regional pain syndrome type I. A pilot study investigating the effects of fast left prefrontal rTMS on chronic neuropathic pain.
To study the analgesic effect of repetitive transcranial magnetic stimulation (rTMS) of the motor cortex on central pain in patients with chronic spinal cord injury (SCI).
                Double-blind randomized controlled trial. Mean follow-up period was 4.5 weeks.
                General hospital.
                Twelve paraplegic patients due to thoracic SCI suffering chronic central pain (11 completed the study) who were randomly selected from a list of eligible patients.
                Real or sham 10 daily motor rTMS treatments (500 trains at 5 Hz for 10 s; total of 500 pulses at intensity of 115% of motor threshold) using figure-of-8 coil over the vertex.
                Chronic pain intensity (visual analog scale [VAS], McGill Pain Questionnaire [MPQ]), pain threshold, and level of depression (Beck Depression Inventory).
                Both real and sham TMS induced a similar, significant reduction in VAS scores (P<.001) immediately after each of the 10 treatment sessions and in VAS and MPQ scores after the end of the treatment series. However, only real rTMS conferred a significant increase in heat-pain threshold (4 degrees C, P<.05) by the end of the series. Most important, the reduction in MPQ scores in the real rTMS group continued during the follow-up period. Depression scores were equally reduced in both groups but similar to pain relief, depression continued to improve at follow-up in the real rTMS group.
                Whereas the pain alleviation induced by a single rTMS treatment is probably due to placebo, patients with SCI may benefit from a series of rTMS treatments. To assess, using a double-blind procedure, the pain-relieving effects of rTMS against placebo, and their predictive value regarding the efficacy of implanted motor cortex stimulation (MCS).
                Three randomised, double-blinded, 25 min sessions of focal rTMS (1 Hz, 20 Hz and sham) were performed in 12 patients, at 2 weeks intervals. Effects on pain were estimated from daily scores across 5 days before, and 6 days after each session. Analgesic effects were correlated with those of subsequent implanted motor cortex stimulation (MCS).
                Immediately after the stimulating session, pain scores were similarly decreased by all rTMS modalities. Conversely, during the following week, 1 Hz stimulation provided significantly less analgesia than 20 Hz and placebo, and was pro-algesic in some patients. Placebo and 20 Hz rTMS were effective on different patients, and only 20 Hz rTMS predicted the efficacy of subsequent MCS, with no false positives.
                While 1Hz rTMS should not be used with analgesic purposes, high-frequency rTMS may become useful to select candidates for MCS. Placebo effects are powerful and should be controlled for. Immediate results after a single rTMS session are misleading.
                Defining rTMS parameters is a crucial step before proposing rTMS as predictive test of SCM efficacy in clinical practice. 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. Improvement in sensory detection thresholds was found to be associated with neuropathic pain relief produced by epidural motor cortex stimulation with surgically implanted electrodes.
                To determine the ability of repetitive transcranial magnetic stimulation (rTMS) of the motor cortex to produce similar sensory changes.
                In 46 patients with chronic neuropathic pain of various origins, first-perception thresholds for thermal (cold, warm) and mechanical (vibration, pressure) sensations were quantified in the painful zone and in the painless homologue contralateral territory, before and after rTMS of the motor cortex corresponding to the painful side. Ongoing pain level was also scored before and after rTMS. Three types of rTMS session, performed at 1 Hz or 10 Hz using an active coil, or at 10 Hz using a sham coil, were compared. The relationships between rTMS-induced changes in sensory thresholds and in pain scores were studied.
                Subthreshold rTMS applied at 10 Hz significantly lowered pain scores and thermal sensory thresholds in the painful zone but did not lower mechanical sensory thresholds. Pain relief correlated with post-rTMS improvement of warm sensory thresholds in the painful zone.
                Thermal sensory relays are potentially dysfunctioning in chronic neuropathic pain secondary to sensitisation or deafferentation-induced disinhibition. By acting on these structures, motor cortex stimulation could relieve pain and concomitantly improve innocuous thermal sensory discrimination. The chronic electrical stimulation of a motor cortical area corresponding to a painful region of the body, by means of surgically-implanted epidural electrodes is a validated therapeutical strategy to control medication-resistant neurogenic pain. Repetitive transcranial magnetic stimulation (rTMS) permits to stimulate non-invasively and precisely the motor cortex. We applied a 20-min session of rTMS of the motor cortex at 10 Hz using a 'real' or a 'sham' coil in a series of 14 patients with intractable pain due to thalamic stroke or trigeminal neuropathy. We studied the effects of rTMS on pain level assessed on a 0-10 visual analogue scale from day 1 to day 12 following the rTMS session. A significant pain decrease was observed up to 8 days after the 'real' rTMS session. This study shows that a transient pain relief can be induced in patients suffering from chronic neurogenic pain during about the week that follows a 20-min session of 10 Hz-rTMS applied over the motor cortex. Chronic electrical stimulation of the precentral (motor) cortex using surgically implanted electrodes is performed to treat medication-resistant neurogenic pain. The goal of this placebo-controlled study was to obtain such antalgic effects by means of a non-invasive cortical stimulation using repetitive transcranial magnetic stimulation (rTMS). Eighteen patients with intractable neurogenic pain of various origins were included and underwent a 20 min session of either 10 Hz, 0.5 Hz or* sham rTMS over the motor cortex in a random order. A significant decrease in the mean pain level of the series was obtained only after 10 Hz rTMS. This study shows that a transient pain relief can be induced by 10 Hz rTMS of the motor cortex in some patients suffering from chronic neurogenic pain. Past evidence has shown that motor cortical stimulation with invasive and non-invasive brain stimulation is effective to relieve central pain. Here we aimed to study the effects of another, very safe technique of non-invasive brain stimulation--transcranial direct current stimulation (tDCS)--on pain control in patients with central pain due to traumatic spinal cord injury. Patients were randomized to receive sham or active motor tDCS (2mA, 20 min for 5 consecutive days). A blinded evaluator rated the pain using the visual analogue scale for pain, Clinician Global Impression and Patient Global Assessment. Safety was assessed with a neuropsychological battery and confounders with the evaluation of depression and anxiety changes. There was a significant pain improvement after active anodal stimulation of the motor cortex, but not after sham stimulation. These results were not confounded by depression or anxiety changes. Furthermore, cognitive performance was not significantly changed throughout the trial in both treatment groups. The results of our study suggest that this new approach of cortical stimulation can be effective to control pain in patients with spinal cord lesion. We discuss potential mechanisms for pain amelioration after tDCS, such as a secondary modulation of thalamic nuclei activity. In complex regional pain syndrome (CRPS) many clinical symptoms suggest involvement of the central nervous system. Neuropathic pain as the leading symptom is often resistant to therapy. In the present study we investigated the analgesic efficiency of repetitive transcranial magnetic simulation (rTMS) applied to the motor cortex contralateral to the CRPS-affected side. Seven out of ten patients reported decreased pain intensities. Pain relief occurred 30 s after stimulation, whereas the maximum effect was found 15 min later. Pain re-intensified increasingly 45 min after rTMS. In contrast, sham rTMS did not alter pain perception. These findings provide evidence that in CRPS I pain perception can be modulated by repetitive motor cortex stimulation. 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.
                This preliminary pilot trial employed a sham-controlled, within-subject, crossover 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 10 Hz left prefrontal repetitive TMS. 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.
                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 two 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.
                The prefrontal cortex may be an important TMS cortical target for managing certain types of pain, including certain neuropathic pain syndromes.
Single doses of high-frequency rTMS of the motor cortex may have small short-term effects on chronic pain. The effects do not clearly exceed the predetermined threshold of minimal clinical significance. Low-frequency rTMS is not effective in the treatment of chronic pain. There is insufficient evidence from which to draw firm conclusions regarding the efficacy of CES or tDCS. The available evidence suggests that tDCS applied to the motor cortex may have short-term effects on chronic pain and that CES may be ineffective. There is a need for further, rigorously designed studies of all types of stimulation.