Phantom pain reduction by low-frequency and low-intensity electromagnetic fields.
Doctoral School of Pharmaceutical and Pharmacological Sciences, Semmelweis University , Budapest , Hungary.
Although various treatments have been presented for phantom pain, there is little proof supporting the benefits of pharmacological treatments, surgery or interventional techniques, electroconvulsive therapy, electrical nerve stimulation, far infrared ray therapy, psychological therapies, etc. Here, we report the preliminary results for phantom pain reduction by low-frequency and intensity electromagnetic fields under clinical circumstances. Our method is called as Electromagnetic-Own-Signal-Treatment (EMOST). Fifteen people with phantom limb pain participated. The patients were treated using a pre-programmed, six sessions. Pain intensity was quantified upon admission using a 0-10 verbal numerical rating scale. Most of the patients (n = 10) reported a marked reduction in the intensity of phantom limb pain. Several patients also reported about improvement in their sleep and mood quality, or a reduction in the frequency of phantom pain after the treatments. No improvements in the reduction of phantom limb pain or sleep and mood improvement were reported in the control group (n = 5). Our nonlinear electromagnetic EMOST method may be a possible therapeutic application in the reduction of phantom limb pain. Here, we also suggest that some of the possible effects of the EMOST may be achieved via the redox balance of the body and redox-related neural plasticity.
Phantom limb pain: low frequency repetitive transcranial magnetic stimulation in unaffected hemisphere.
Department of Psychiatry, University of Florence, 50134 Florence, Italy.
Phantom limb pain is very common after limb amputation and is often difficult to treat. The motor cortex stimulation is a valid treatment for deafferentation pain that does not respond to conventional pain treatment, with relief for 50% to 70% of patients. This treatment is invasive as it uses implanted epidural electrodes. Cortical stimulation can be performed noninvasively by repetitive transcranial magnetic stimulation (rTMS). The stimulation of the hemisphere that isn’t involved in phantom limb (unaffected hemisphere), remains unexplored. We report a case of phantom limb pain treated with 1 Hz rTMS stimulation over motor cortex in unaffected hemisphere. This stimulation produces a relevant clinical improvement of phantom limb pain; however, further studies are necessary to determine the efficacy of the method and the stimulation parameters.
Repetitive transcranial magnetic stimulation of the parietal cortex transiently ameliorates phantom limb pain-like syndrome.
Department of Neurology, Universitätsklinikum Aachen, Pauwelsstrasse 30, RWTH D-52057 Aachen, Germany.
Phantom pain is linked to a reorganization of the partially deafferented sensory cortex. In this study we have investigated whether the pain syndrome can be influenced by repetitive transcranial magnetic stimulation (rTMS).
Two patients with a longstanding unilateral avulsion of the lower cervical roots and chronic pain in the arm were studied. As a control the acute effects of rTMS (15 Hz, 2 s duration) on pain were studied in 4 healthy subjects. Pain intensity was assessed with the Visual Analogue Scale.
Stimulation of the contralateral parietal cortex led to a reproducible reduction in pain intensity lasting up to 10 min. Stimulation of other cortical areas produced only minor alterations in the severity of the pain. Both 1 and 10 Hz rTMS trains applied to the contralateral parietal cortex on weekdays for 3 consecutive weeks did, however, not lead to permanent changes in the pain intensity. Experimentally induced pain (cold water immersion of the right hand) in normal subjects was not influenced by rTMS.
These results do not favor the use of rTMS in the treatment of phantom limb pain. The results, however, support the concept that phantom pain is due to a dysfunctional activity in the parietal cortex. The transient rTMS-induced analgesic effect may be due to a temporary interference with the cerebral representation of the deafferented limb.