Transcranial DC Stimulation Coupled With TENS for the Treatment of Chronic Pain A Preliminary Study

Objective: Based on evidence showing that electrical stimulation of the nervous system is an effective method to decrease chronic neurogenic pain, we aimed to investigate whether the combination of 2 methods of electrical stimulation-a method of peripheral stimulation [transcutaneous electrical nerve stimulation (TENS)] and a method of noninvasive brain stimulation (transcranial direct current stimulation (tDCS)]-induces greater pain reduction as compared with tDCS alone and sham stimulation. Methods: We performed a preliminary, randomized, sham-controlled, crossover, clinical study in which 8 patients were randomized to receive active tDCS/active TENS (""tDCS/TENS"" group), active tDCS/sham TENS (""tDCS"" group), and sham tDCS/sham TENS (""sham"" group) stimulation. Assessments were performed immediately before and after each condition by a blinded rater. Results: The results showed that there was a significant difference in pain reduction across the conditions Of stimulation (P = 0.006). Post hoc tests showed significant pain reduction as compared with baseline after the tDCS/TENS condition [reduction by 36.5% (+/- 10.7), P = 0.004] and the tDCS condition [reduction by 15.5% (+/- 4.9), P = 0.014], but not after sham stimulation (P = 0.35). In addition, tDCS/TENS induced greater pain reduction than tDCS (P = 0.02). Conclusions: The results of this pilot study suggest that the combination of TENS with tDCS has a superior effect compared with tDCS alone.

Cognitive function in patients with chronic pain treated with opioids: characteristics and associated factors

Background The paucity of studies regarding cognitive function in patients with chronic pain, and growing evidence regarding the cognitive effects of pain and opioids on cognitive function prompted us to assess cognition via neuropsychological measurement in patients with chronic non-cancer pain treated with opioids. Methods In this cross-sectional study, 49 patients were assessed by Continuous Reaction Time, Finger Tapping, Digit Span, Trail Making Test-B and Mini-mental State Examination tests. Linear regressions were applied. Results Patients scored poorly in the Trail Making Test-B (mean?=?107.6?s, SD?=?61.0, cut-off?=?91?s); and adequately on all other tests. Several associations among independent variables and cognitive tests were observed. In the multiple regression analyses, the variables associated with statistically significant poor cognitive performance were female sex, higher age, lower annual income, lower schooling, anxiety, depression, tiredness, lower opioid dose, and more than 5?h of sleep the night before assessment (P?<?0.05). Conclusions Patients with chronic pain may have cognitive dysfunction related to some reversible factors, which can be optimized by therapeutic interventions.

Chronic Pain and Depression in the Quality of Life of Women With Migraine - A Controlled Study

Background. Migraine is comorbid to depression and widespread chronic pain (WCP), but the influence of these conditions on the health-related quality of life (HRQoL) of individuals with episodic (EM) and chronic migraine (CM) is poorly understood. Objective.-To assess the prevalence of depressive symptoms and WCP in individuals with EM and CM, as well as to estimate the joint impact of these conditions on the HRQoL of these individuals. Methods.-All women aged 18 to 65 years with a first diagnosis of EM or CM from September of 2006 to September of 2008 seen in an outpatient headache service were invited to participate. They were asked to attend a separate appointment in the service, and to bring another woman of similar age that also agreed to participate. Depressive symptoms were assessed using the Beck Depression Inventory. Questions about WCP followed the protocol of the American College of Rheumatology. HRQoL was assessed using the Short-Form 36 (SF-36). Multivariate analysis modeled HRQoL as a function of headache status, depressive symptoms, and pain, using quantile regression. Results.-Sample consisted of 179 women, 53 in the EM group, 37 in the CM group and 89 in control group. Groups did not differ by demographics. Mean scores of SF-36 were 53.6 (standard deviation [SD] = 23.5) for EM, 44.2 (SD = 18.5) for CM and 61.8 (SD = 21.5) for controls. In multivariate analysis, SF-36 scores were predicted by a CM status (P =.02; -10.05 [95% CI -18.52; -1.58]) and by a Beck Depression Inventory score (P <.01; -1.27 [95% CI -1.55; -0.99]). The influence of WCP in the SF-36 scores approached significance (P =.08; -0.78 [95% CI -1.64; 0.88]). Age did not contribute to the model. Conclusion.-Women with migraine are at an increased chance of WCP, and the chance increases as a function of headache frequency. Both depressive symptoms and CM independently predict HRQoL status.

Chronic Pain after Cesarean Section. Influence of Anesthetic/Surgical Technique and Postoperative Analgesia

Cancado TO, Omais M, Ashmawi HA, Torres MLA - Chronic Pain after Cesarean Section. Influence of Anesthetic/Surgical Technique and Postoperative Analgesia. Background and objectives: Brazil ranks second among countries with the highest rates of cesarean section in the world. Little is known about the future consequences of this procedure on maternal health. This study investigated the influence of anesthetic/surgical technique and postoperative analgesia on the onset of chronic pain after three months of cesarean section. Method: This is a prospective randomized study of 443 patients undergoing cesarean section (elective and emergency), with different doses of hyperbaric bupivacaine 0.5% and opioids in spinal anesthesia. Patients were alocated into five groups as follow: G1 received hyperbaric bupivacaine (8 mg), sufentanil (2.5 mu g), and morphine (100 mu g); G2 received hyperbaric bupivacaine (10 mg), sufentanil (2.5 mu g), and morphine (100 mu g); G3 received hyperbaric bupivacaine (12.5 mg) and morphine (100 mu g); G4 received hyperbaric bupivacaine (15 mg) and morphine (100 mu g); G5 received hyperbaric bupivacaine (12.5 mg) and morphine (100 mu g), without perioperative anti-inflammatory. Pain at rest and in movement were evaluated in the immediate postoperative period. Phone contact was made after three months of surgery for identification of patients with chronic pain. Results: The incidence of chronic pain in the groups was G1 = 20%; G2 = 13%; G3 = 7.1%; G4 = 2.2%, and G5 = 20.3%. Patients who reported higher pain scores in the postoperative period had a higher incidence of chronic pain (p < 0.05). Conclusion: The incidence of chronic pain decreases with higher doses of local anesthetics and use of anti-inflammatory drugs. The higher pain scores in the postoperative period were associated with chronic pain development after three months of cesarean section.

Chronic pain associated with the Chikungunya Fever: long lasting burden of an acute illness

Abstract Background Chikungunya virus (CHIKV) is responsible for major epidemics worldwide. Autochthonous cases were recently reported in several European countries. Acute infection is thought to be monophasic. However reports on chronic pain related to CHIKV infection have been made. In particular, the fact that many of these patients do not respond well to usual analgesics suggests that the nature of chronic pain may be not only nociceptive but also neuropathic. Neuropathic pain syndromes require specific treatment and the identification of neuropathic characteristics (NC) in a pain syndrome is a major step towards pain control. Methods We carried out a cross-sectional study at the end of the major two-wave outbreak lasting 17 months in Réunion Island. We assessed pain in 106 patients seeking general practitioners with confirmed infection with the CHIK virus, and evaluated its impact on quality of life (QoL). Results The mean intensity of pain on the visual-analogical scale (VAS) was 5.8 ± 2.1, and its mean duration was 89 ± 2 days. Fifty-six patients fulfilled the definition of chronic pain. Pain had NC in 18.9% according to the DN4 questionnaire. Conversely, about two thirds (65%) of patients with NC had chronic pain. The average pain intensity was similar between patients with or without NC (6.0 ± 1.7 vs 6.1 ± 2.0). However, the total score of the Short Form-McGill Pain Questionnaire (SF-MPQ)(15.5 ± 5.2 vs 11.6 ± 5.2; p < 0.01) and both the affective (18.8 ± 6.2 vs 13.4 ± 6.7; p < 0.01) and sensory subscores (34.3 ± 10.7 vs 25.0 ± 9.9; p < 0.01) were significantly higher in patients with NC. The mean pain interference in life activities calculated from the Brief Pain Inventory (BPI) was significantly higher in patients with chronic pain than in patients without it (6.8 ± 1.9 vs 5.9 ± 1.9, p < 0.05). This score was also significantly higher in patients with NC than in those without such a feature (7.2 ± 1.5 vs 6.1 ± 1.9, p < 0.05). Conclusions There exists a specific chronic pain condition associated to CHIKV. Pain with NC seems to be associated with more aggressive clinical picture, more intense impact in QoL and more challenging pharmacological treatment.

The effect of intrathecal gabapentin on neuropathic pain is independent of the integrity of the dorsolateral funiculus in rats

Aim: This study evaluates the contribution of inhibitory pain pathways that descend to the spinal cord through the dorsolateral funiculus (DLF) on the effect of intrathecal gabapentin against spinal nerve ligation (SNL)-induced behavioral hypersensitivity to mechanical stimulation in rats. Main method: Rats were submitted to a sham or complete ligation of the right LS and L6 spinal nerves and a sham or complete DLF lesion. Next, the changes induced by intrathecal administration of gabapentin on the paw withdrawal threshold of rats to mechanical stimulation were evaluated electronically. Key findings: Intrathecal gabapentin (200 mu g/5 mu l) that was injected 2 or 7 days after surgery fully inhibited the SNL-induced behavioral hypersensitivity to mechanical stimulation in sham DLF-Iesioned rats; gabapentin was effective against the SNL-induced behavioral hypersensitivity to mechanical stimulation also in DLF-Iesioned rats. Significance: The effect of intrathecally administered gabapentin against SNL-induced behavioral hypersensitivity to mechanical stimulation in rats does not depend on the activation of nerve fibers that descend to the spinal cord via the DLF. (C) 2012 Elsevier Inc. All rights reserved.

Plasma corticosterone levels in mouse models of pain

Background: Pain markedly activates the hypothalamic-pituitary-adrenal (HPA) axis and increases plasma corticosterone release interfering significantly with nociceptive behaviour as well as the mechanism of action of analgesic drugs. Aims/Methods: In the present study, we monitored the time course of circulating corticosterone in two mouse strains (C57Bl/6 and Balb/C) under different pain models. In addition, the stress response was investigated following animal handling, intrathecal (i.t.) manipulation and habituation to environmental conditions commonly used in nociceptive experimental assays. We also examined the influence of within-cage order of testing on plasma corticosterone. Results: Subcutaneous injection of capsaicin precipitated a prompt stress response whereas carrageenan and complete Freund's adjuvant induced an increased corticosterone release around the third hour post-injection. However, carrageenan induced a longer increased corticosterone in C57Bl/6 mice. In partial sciatic nerve ligation, neuropathic pain model corticosterone increased only in the first days whereas mechanical hypersensitivity remained much longer. Animal handling also represents an important stressor whereas the i.t. injection per se does not exacerbate the handling-induced stress response. Moreover, the order of testing animals from the same cage does not interfere with plasma corticosterone levels in the intrathecal procedure. Animal habituation to the testing apparatus also does not reduce the immediate corticosterone increase as compared with non-habituated mice. Conclusion: Our data indicate that HPA axis activation in acute and chronic pain models is time dependent and may be dissociated from evoked hyperalgesia. Therefore, HPA-axis activation represents an important variable to be considered when designing experimental assays of persistent pain as well as for interpretation of data.

Can the `yin and yang` BDNF hypothesis be used to predict the effects of rTMS treatment in neuropsychiatry?

Repetitive transcranial magnetic stimulation (rTMS) is a novel technique of non-invasive brain stimulation which has been used to treat several neuropsychiatric disorders such as major depressive disorder, chronic pain and epilepsy. Recent studies have shown that the therapeutic effects of rTMS are associated with plastic changes in local and distant neural networks. In fact, it has been suggested that rTMS induces long-term potentiation (LTP) and long-term depression (LTD) - like effects. Besides the initial positive clinical results; the effects of rTMS are stilt mixed. Therefore new toots to assess the effects of plasticity non-invasively might be useful to predict its therapeutic effects and design novel therapeutic approaches using rTMS. In this paper we propose that brain-derived neurotrophic factor (BDNF) might be such a tool. Brain-derived neurotrophic factor is a neurotrophin that plays a key role in neuronal survival and synaptic strength, which has also been studied in several neuropsychiatric disorders. There is robust evidence associating BDNF with the LTP/LTD processes, and indeed it has been proposed that BNDF might index an increase or decrease of brain activity - the `yin and yang` BDNF hypothesis. In this article, we review the initial studies combining measurements of BDNF in rTMS clinical trials and discuss the results and potential usefulness of this instrument in the field of rTMS. (C) 2008 Elsevier Ltd. All rights reserved.

Into the Island: A new technique of non-invasive cortical stimulation of the insula

Study aim. - We describe a new neuronavigation-guided technique to target the posterior-superior insula (PSI) using a cooled-double-cone coil for deep cortical stimulation. Introduction. - Despite the analgesic effects brought about by repetitive transcranial magnetic stimulation (TMS) to the primary motor and prefrontal cortices, a significant proportion of patients remain symptomatic. This encouraged the search for new targets that may provide stronger pain relief. There is growing evidence that the posterior insula is implicated in the integration of painful stimuli in different pain syndromes and in homeostatic thermal integration. Methods. - The primary motor cortex representation of the lower leg was used to calculate the motor threshold and thus, estimate the intensity of PSI stimulation. Results. - Seven healthy volunteers were stimulated at 10 Hz to the right PSI and showed subjective changes in cold perception. The technique was safe and well tolerated. Conclusions. - The right posterior-superior insula is worth being considered in future studies as a possible target for rTMS stimulation in chronic pain patients. (c) 2012 Elsevier Masson SAS. All rights reserved.

Cytokine inhibition and time-related influence of inflammatory stimuli on the hyperalgesia induced by the nucleus pulposus

The symptoms of lumbar disc herniation, such as low back pain and sciatica, have been associated with local release of cytokines following the inflammatory process induced by the contact of the nucleus pulposus (NP) with the spinal nerve. Using an animal experimental model of intervertebral disc herniation and behavioral tests to evaluate mechanical (electronic von Frey test) and thermal (Hargreaves Plantar test) hyperalgesia in the hind paw of rats submitted to the surgical model, this study aimed to detect in normal intervertebral disc the cytokines known to be involved in the mechanisms of inflammatory hyperalgesia, to observe if previous exposure of the intervertebral disc tissue to specific antibodies could affect the pain behavior (mechanical and thermal hyperalgesia) induced by the NP, and to observe the influence of the time of contact of the NP with the fifth lumbar dorsal root ganglion (L5-DRG) in the mechanical and thermal hyperalgesia. The cytokines present at highest concentrations in the rat NP were TNF-alpha, IL-1 beta and CINC-1. Rats submitted to the disc herniation experimental model, in which a NP from the sacrococcygeal region is deposited over the right L5-DRG, showed increased mechanical and thermal hyperalgesia that lasted at least 7 weeks. When the autologous NP was treated with antibodies against the three cytokines found at highest concentrations in the NP (TNF-alpha, IL-1 beta and CINC-1), there was decrease in both mechanical and thermal hyperalgesia in different time points, suggesting that each cytokine may be important for the hyperalgesia in different steps of the inflammatory process. The surgical remotion of the NP from herniated rats 1 week after the implantation reduced the hyperalgesia to the level similar to the control group. This reduction in the hyperalgesia was also observed in the group that had the NP removed 3 weeks after the implantation, although the intensity of the hyperalgesia did not decreased totally. The removal of the NP after 5 weeks did not changed the hyperalgesia observed in the hind paw, which suggests that the longer the contact of the NP with the DRG, the greater is the possibility of development of chronic pain. Together our results indicate that specific cytokines released during the inflammatory process induced by the herniated intervertebral disc play fundamental role in the development of the two modalities of hyperalgesia (mechanical and thermal) and that the maintenance of this inflammation may be the most important point for the chronification of the pain.

Sleep disorders in climacteric women

Introduction: This paper examines the various factors that contribute to the occurrence of sleep alterations during peri and post climacteric and thus produce significant imperil to women's quality of life. Among the probable causes of insomnia or sleep disorders associated to climacteric stand out the occurrence of vasomotor symptoms, depressive state and respiratory distress during sleep, such as sleep apnea, along with chronic pain, although psychosocial factors related to the climacteric bear major influence on such clinical status. Method: The bibliographic analysis was carried out using several electronic data base namely: Cochrane, Medline, Embase, Bni Plus, Biological Abstracts, Psycinfo, Web Of Science, Sigle, Dissertation Abstracts and ZETOC published in English, Spanish and Poruguese. The key terms used were: sleep, REM sleep, slow wave sleep polysomnography; electroencephalogram; sleep disturbances; disturbances of sleep onset and maintenance; excessive somnolence disturbances; climacteric; menopause; depression; neurobiology; biologic models; circadian rhythm; mental health and epidemiology. Case studies and letters to the editor were excluded. The summaries of the identified studies found in the data base were analyzed and assessed, and the data analyzed separately according to the subjective or objective criteria for data collection. Results: The climacteric transition constitutes a period of major risk for the development of depressive, vasomotor and insomnia symptoms although not caused solely by hypoestrogenism. The diagnostic methods used in the study of sleep disorders range from subjective assessment by means of response to specific questionnaires to the objective analysis of actigraphic or polissonographic daytime and nocturnal reports. Polissonographic studies of the whole night, performed at the laboratory, are the golden method of choice for diagnostic of sleep disorders. Studies point to the high prevalence of sleep disorders in the climacteric, especially insomnia, apnea and periodic movement of legs and also to the fact that this phase of life presents decrease in the quality of sleep. Women in peri and post climacteric show higher sleep latency and difficulty in its maintenance and refer being less satisfied with its quality even when compared to those who are not climacteric. Exception made to the vasomotor symptomatology, the other climacteric complaints such as mood disturbances, libido alterations, cognitive deficit, articular pain and sleep disorders are markedly associated to psychosocial factors, lifestyle and especially to women's perception of what the climacteric means to their lives. Conclusion: The analysis of the available studies revealed a proneness to deterioration of quality of life of climacteric women markedly in the sleep disturbances, depressed mood and anxiety domains and should not to be basically attributed to the climacteric. It is necessary that the professionals consider the need of assessment of such pathologies as complex phenomena and the literature lacks studies contemplating such dimensions.

Subthalamic deep brain stimulation modulates small fiber-dependent sensory thresholds in Parkinson's disease

The effects of deep brain stimulation of the subthalamic nucleus on nonmotor symptoms of Parkinson's disease (PD) rarely have been investigated. Among these, sensory disturbances, including chronic pain (CP), are frequent in these patients. The aim of this study was to evaluate the changes induced by deep brain stimulation in the perception of sensory stimuli, either noxious or innocuous, mediated by small or large nerve fibers. Sensory detection and pain thresholds were assessed in 25 PD patients all in the off-medication condition with the stimulator turned on or off (on- and off-stimulation conditions, respectively). The relationship between the changes induced by surgery on quantitative sensory testing, spontaneous CP, and motor abilities were studied. Quantitative sensory test results obtained in PD patients were compared with those of age-matched healthy subjects. Chronic pain was present in 72% of patients before vs 36% after surgery (P = .019). Compared with healthy subjects, PD patients had an increased sensitivity to innocuous thermal stimuli and mechanical pain, but a reduced sensitivity to innocuous mechanical stimuli. In addition, they had an increased pain rating when painful thermal stimuli were applied, particularly in the off-stimulation condition. In the on-stimulation condition, there was an increased sensitivity to innocuous thermal stimuli but a reduced sensitivity to mechanical or thermal pain. Pain provoked by thermal stimuli was reduced when the stimulator was turned on. Motor improvement positively correlated with changes in warm detection and heat pain thresholds. Subthalamic nucleus deep brain stimulation contributes to relieve pain associated with PD and specifically modulates small fiber-mediated sensations. (C) 2012 International Association for the Study of Pain. Published by Elsevier B. V. All rights reserved.

Eficácia da desativação dos pontos-gatilho miofasciais para o controle do zumbido

Dor crônica nas imediações do ouvido pode influenciar o zumbido. OBJETIVO: Investigar a eficácia da desativação de pontos-gatilho miofasciais na melhora do zumbido. MÉTODO: Ensaio clínico randomizado com 71 pacientes com zumbido e síndrome dolorosa miofascial. O Grupo Experimental (n = 37) foi submetido a 10 sessões de desativação dos pontos-gatilho miofasciais e o Grupo Controle (n = 34), a 10 sessões de desativação placebo. RESULTADOS: O tratamento do Grupo Experimental foi eficaz para o controle do zumbido (p < 0,001). Houve associação entre as melhoras de dor e zumbido (p = 0,013) e entre os lados da orelha com pior zumbido e do corpo com mais dor (p < 0,001). A presença de modulação (aumento ou diminuição) temporária do zumbido durante a palpação inicial dos pontos foi frequente em ambos os grupos, mas a diminuição temporária foi associada à melhora persistente do zumbido ao fim do tratamento (p = 0,002). CONCLUSÃO: Além da avaliação médica e audiológica, os pacientes com zumbido devem ser avaliados para: 1) presença de dor miofascial próxima à orelha; 2) lateralidade entre ambos os sintomas; 3) diminuição temporária do zumbido durante a palpação do músculo dolorido. O tratamento deste subgrupo de pacientes pode ter melhor prognóstico que os demais.

Psychometric properties of the Spanish version of the mindful attention awareness scale (MAAS) in patients with fibromyalgia

Background Mindful-based interventions improve functioning and quality of life in fibromyalgia (FM) patients. The aim of the study is to perform a psychometric analysis of the Spanish version of the Mindful Attention Awareness Scale (MAAS) in a sample of patients diagnosed with FM. Methods The following measures were administered to 251 Spanish patients with FM: the Spanish version of MAAS, the Chronic Pain Acceptance Questionnaire, the Pain Catastrophising Scale, the Injustice Experience Questionnaire, the Psychological Inflexibility in Pain Scale, the Fibromyalgia Impact Questionnaire and the Euroqol. Factorial structure was analysed using Confirmatory Factor Analyses (CFA). Cronbach's α coefficient was calculated to examine internal consistency, and the intraclass correlation coefficient (ICC) was calculated to assess the test-retest reliability of the measures. Pearson’s correlation tests were run to evaluate univariate relationships between scores on the MAAS and criterion variables. Results The MAAS scores in our sample were low (M = 56.7; SD = 17.5). CFA confirmed a two-factor structure, with the following fit indices [sbX2 = 172.34 (p < 0.001), CFI = 0.95, GFI = 0.90, SRMR = 0.05, RMSEA = 0.06. MAAS was found to have high internal consistency (Cronbach’s α = 0.90) and adequate test-retest reliability at a 1–2 week interval (ICC = 0.90). It showed significant and expected correlations with the criterion measures with the exception of the Euroqol (Pearson = 0.15). Conclusion Psychometric properties of the Spanish version of the MAAS in patients with FM are adequate. The dimensionality of the MAAS found in this sample and directions for future research are discussed.

Dor crônica pós-cesariana. Influência da técnica anestésico-cirúrgica e da analgesia pós-operatória

JUSTIFICATIVA E OBJETIVOS: O Brasil ocupa o segundo lugar entre os países com maiores taxas de cesariana no mundo. Pouco se sabe a respeito das consequências futuras desse procedimento sobre a saúde materna. Este estudo investigou a influência da técnica anestésico-cirúrgica e da analgesia pós-operatória no aparecimento de dor crônica após três meses da cesariana. MÉTODO: Este estudo prospectivo randomizado foi feito em 443 pacientes submetidas a cesariana (eletiva e urgente), com diferentes doses de bupivacaína 0,5% hiperbárica e opioides na raquianestesia. Os grupos foram: G1- 8 mg bupivacaína hiperbárica + 2,5 mg sufentanil + 100 mg morfina; G2- 10 mg bupivacaína hiperbárica + 2,5 mg sulfentanil + 100 mg morfina; G3- 12,5 mg bupivacaína hiperbárica + 100 mg morfina; G4- 15 mg bupivacaína hiperbárica + 100 mg morfina; G5- 12,5 mg bupivacaína hiperbárica + 100 mg morfina (sem anti-inflamatório perioperatório). Dor em repouso e em movimento foram avaliadas no pós-operatório imediato. Contato telefônico foi feito, após três meses do procedimento cirúrgico, para identificação das pacientes com dor crônica. RESULTADOS: A incidência de dor crônica nos grupos foi: G1 = 20%; G2 = 13%; G3 = 7,1%; G4 = 2,2% e G5 = 20,3%. Pacientes que referiram escores de dor mais elevados no período pós-operatório tiveram maior incidência de dor crônica (p < 0,05). CONCLUSÃO: A incidência de dor crônica diminui com o emprego de doses maiores de anestésicos locais e uso de anti-inflamatórios não hormonais. Escores mais elevados de dor no período pós-operatório tiveram associação com aparecimento de dor crônica após três meses da cesariana.