Non-invasive brain stimulation techniques for chronic pain (review)

Background This is an updated version of the original Cochrane review published in 2010, Issue 9. Non-invasive brain stimulation techniques aim to induce an electrical stimulation of the brain in an attempt to reduce chronic pain by directly altering brain activity. They include repetitive transcranial magnetic stimulation (rTMS), cranial electrotherapy stimulation (CES), transcranial direct current stimulation (tDCS) and reduced impedance non-invasive cortical electrostimulation (RINCE). Objectives To evaluate the efficacy of non-invasive brain stimulation techniques in chronic pain. Search methods We searched CENTRAL (2013, Issue 6), MEDLINE, EMBASE, CINAHL, PsycINFO, LILACS and clinical trials registers. The original search for the review was run in November 2009 and searched all databases from their inception. To identify studies for inclusion in this update we searched from 2009 to July 2013. Selection criteria Randomised and quasi-randomised studies of rTMS, CES, tDCS or RINCE if they employed a sham stimulation control group, recruited patients over the age of 18 with pain of three months duration or more and measured pain as a primary outcome. Data collection and analysis Two authors independently extracted and verified data. Where possible we entered data into meta-analyses. We excluded studies judged as being at high risk of bias from the analysis. We used the GRADE system to summarise the quality of evidence for core comparisons. Main results We included an additional 23 trials (involving 773 participants randomised) in this update, making a total of 56 trials in the review (involving 1710 participants randomised). This update included a total of 30 rTMS studies, 11 CES, 14 tDCS and one study of RINCE(the original review included 19 rTMS, eight CES and six tDCS studies). We judged only three studies as being at low risk of bias across all criteria. Meta-analysis of studies of rTMS (involving 528 participants) demonstrated significant heterogeneity. Pre-specified subgroup analyses suggest that low-frequency stimulation is ineffective (low-quality evidence) and that rTMS applied to the dorsolateral prefrontal cortex is ineffective (very low-quality evidence). We found a short-term effect on pain of active high-frequency stimulation of the motor cortex in single-dose studies (low-quality evidence, standardised mean difference (SMD) 0.39 (95% confidence interval (CI) -0.27 to -0.51 P \u3c 0.01)). This equates to a 12% (95% CI 8% to 15%) reduction in pain, which does not exceed the pre-established criteria for a minimal clinically important difference (≥ 15%). Evidence for multiple-dose studies was heterogenous but did not demonstrate a significant effect (very low-quality evidence). For CES (six studies, 270 participants) no statistically significant difference was found between active stimulation and sham (low-quality evidence). Analysis of tDCS studies (11 studies, 193 people) demonstrated significant heterogeneity and did not find a significant difference between active and sham stimulation (very low-quality evidence). Pre-specified subgroup analysis of tDCS applied to the motor cortex (n = 183) did not demonstrate a statistically significant effect and this lack of effect was consistent for subgroups of single or multiple-dose studies. One small study (n = 91) at unclear risk of bias suggested a positive effect of RINCE over sham stimulation on pain (very low-quality evidence). Non-invasive brain stimulation appears to be frequently associated with minor and transient side effects, though there were two reported incidences of seizure related to active rTMS in the included studies. Authors\u27 conclusions Single doses of high-frequency rTMS of the motor cortex may have small short-term effects on chronic pain. It is likely that multiple sources of bias may exaggerate this observed effect. The effects do not meet the predetermined threshold of minimal clinical significance and multiple-dose studies do not consistently demonstrate effectiveness. The available evidence suggests that low-frequency rTMS, rTMS applied to the pre-frontal cortex, CES and tDCS are not effective in the treatment of chronic pain. While the broad conclusions for rTMS and CES have not changed substantially, the addition of this new evidence and the application of the GRADE system has modified some of our interpretation and the conclusion regarding the effectiveness of tDCS has changed. We recommend that previous readers should re-read this update. There is a need for larger, rigorously designed studies, particularly of longer courses of stimulation. It is likely that future evidence may substantially impact upon the presented results

Non-invasive brain stimulation techniques for chronic pain

Stimulating the brain without surgery in the management of chronic pain in adults Bottom line: There is a lack of high-quality evidence to support or refute the effectiveness of non-invasive brain stimulation techniques for chronic pain. Background: Electrical stimulation of the brain has been used to address a variety of painful conditions. Various devices are available that can electrically stimulate the brain without the need for surgery or any invasive treatment. There are five main treatment types: repetitive transcranial magnetic stimulation (rTMS) in which the brain is stimulated by a coil applied to the scalp, cranial electrotherapy stimulation (CES) in which electrodes are clipped to the ears or applied to the scalp, transcranial direct current stimulation (tDCS), reduced impedance non-invasive cortical electrostimulation (RINCE) and transcranial random noise stimulation (tRNS) in which electrodes are applied to the scalp. These have been used to try to reduce pain by aiming to alter the activity of the brain. How effective they are is uncertain. Study characteristics: This review update included 94 randomised controlled studies: 42 of rTMS, 11 of CES, 36 of tDCS two of RINCE, two of tRNS and one study which evaluated both tDCS and rTMS. Key findings: rTMS applied to the motor cortex may lead to small, short-term reductions in pain but these effects are not likely to be clinically important. tDCS may reduce pain when compared with sham but for rTMS and tDCS our estimates of benefit are likely to be exaggerated by the small number of participants in each of the studies and limitations in the way the studies were conducted. Low- or very low-quality evidence suggests that low-frequency rTMS and rTMS that is applied to prefrontal areas of the brain are not effective. Low-quality evidence does not suggest that CES is an effective treatment for chronic pain. For all forms of stimulation the evidence is not conclusive and there is substantial uncertainty about the possible benefits and harms of the treatment. Of the studies that clearly reported side effects, short-lived and minor side effects such as headache, nausea and skin irritation were usually reported both with real and sham stimulation. Two cases of seizure were reported following real rTMS. Our conclusions for rTMS, CES, tDCS, and RINCE have not changed substantially in this update. Quality of the evidence: We rated the quality of the evidence from studies using four levels: very low, low, moderate, or high. Very low-quality evidence means that we are very uncertain about the results. High-quality evidence means that we are very confident in the results. We considered all of the evidence to be of low or very low quality, mainly because of bias in the studies that can lead to unreliable results and the small size of the studies, which makes them imprecise

Influence of a walking aid on temporal and spatial parameters of gait in healthy adults

This is the post-print version of the final paper published in PM&R. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2014 Elsevier B.V.Objective - To determine the effect of using a walking aid on temporal and spatial parameters of gait when used for balance versus support on the dominant and nondominant hand side. Design - Repeated measures observational study design. Setting - University gymnasium. Participants - Twenty-seven healthy male and female adults of mean ± standard deviation age 44.74 ± 10.00 years. Methods - Five walking conditions (C) were completed by all participants on the GAITRite pressure mat. Normal walking (C1), walking with a cane in the dominant hand (C2) and nondominant hand (C3) as if using for balance, walking with a cane in the dominant hand (C4) and nondominant hand (C5) while allowing approximately 10% of the body weight through the cane. Main Outcome Measurements - Temporal measurements (swing time, stance time, single limb support time, double limb support time) as percentage of a gait cycle and the base of support for the left and the right foot for all 5 walking conditions. Results - A significant difference (P < .001) was observed between C1, C2, and C3 in percentage swing time and percentage stance time of the ipsilateral side, and in percentage single limb support time of the contralateral side. The double limb support time was significantly different (P ≤ .04) for both ipsilateral and contralateral sides. Comparisons among C1, C4, and C5 demonstrated significance (P < .001) for all variables. Post hoc analysis showed significance between C1 and C4, and C1 and C5 for all variables except percentage stance time of the ipsilateral side and percentage single limb support of the contralateral side. Conclusions - In healthy adults, use of a cane for balance modifies swing and stance parameters of the ipsilateral side and does not affect the base of support formed by the feet. When used for support, the cane alters the swing and stance parameters, and also the base of support formed by the feet

Brain stimulation in the treatment of chronic pain: A narrative review

Electrical brain stimulation techniques have been explored as a method of treating chronic pain via the modulation of brain activity. This narrative review paper provides an outline of the history of this treatment approach, outlines some common methods of brain stimulation with a particular focus on non-invasive brain stimulation (NIBS) techniques, explores the proposed mechanisms by which they might alter pain and summarises the findings of our recent Cochrane review into the efficacy of NIBS techniques for chronic pain

Non-invasive brain stimulation techniques for chronic pain. A report of a Cochrane systematic review and meta-analysis

BACKGROUND: Non-invasive brain stimulation techniques aim to induce an electrical stimulation of the brain in an attempt to reduce chronic pain by directly altering brain activity. They include repetitive transcranial magnetic stimulation (rTMS), cranial electrotherapy stimulation (CES) and transcranial direct current stimulation (tDCS). AIM: To evaluate the efficacy of non-invasive brain stimulation techniques in chronic pain. DESIGN: A Cochrane systematic review with meta-analyses. METHODS: We employed a comprehensive search strategy. Randomised and quasi-randomised studies of rTMS, CES or tDCS were included if they employed a sham stimulation control group, recruited patients over the age of 18 with pain of three months duration or more and measured pain as a primary outcome. Where possible we entered data into meta-analyses. RESULTS: We included 33 trials in the review (19 rTMS, eight CES and six tDCS). Only one study was judged as being at low risk of bias. Studies of rTMS demonstrated significant heterogeneity. Pre-specified subgroup analyses suggest that low-frequency stimulation is ineffective. A short-term effect on pain of active high-frequency stimulation of the motor cortex in single-dose studies was suggested (standardised mean difference (SMD) -0.40, 95% confidence interval (CI) -0.26 to -0.54, P 15%). For CES (four studies, 133 participants) no statistically significant difference was found between active stimulation and sham. Analysis of tDCS studies (five studies, 83 people) demonstrated significant heterogeneity and did not find a significant difference between active and sham stimulation. Pre-specified subgroup analysis of tDCS applied to the motor cortex suggested superiority of active stimulation over sham (SMD -0.59, 95% CI -1.10 to -0.08). Non-invasive brain stimulation appears to be associated with minor and transient side effects. CONCLUSION: 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

Self-reported assessment of disability and performance-based assessment of disability are influenced by different patient characteristics in acute low back pain

For an individual, the functional consequences of an episode of low back pain is a key measure of their clinical status. Self-reported disability measures are commonly used to capture this component of the back pain experience. In non-acute low back pain there is some uncertainty of the validity of this approach. It appears that self-reported assessment of disability and direct measurements of functional status are only moderately related. In this cross-sectional study, we investigated this relationship in a sample of 94 acute low back pain patients. Both self-reported disability and a performance-based assessment of disability were assessed, along with extensive profiling of patient characteristics. Scale consistency of the performance-based assessment was investigated using Cronbach’s alpha, the relationship between self-reported and performance-based assessment of disability was investigated using Pearson’s correlation. The relationship between clinical profile and each of the disability measures were examined using Pearson’s correlations and multivariate linear regression. Our results demonstrate that the battery of tests used are internally reliable (Cronbach’s alpha = 0.86). We found only moderate correlations between the two disability measures (r = 0.471, p < 0.001). Self-reported disability was significantly correlated with symptom distribution, medication use, physical well-being, pain intensity, depression, somatic distress and anxiety. The only significant correlations with the performance-based measure were symptom distribution, physical well-being and pain intensity. In the multivariate analyses no psychological measure made a significant unique contribution to the prediction of the performance-based measure, whereas depression made a unique contribution to the prediction of the self-reported measure. Our results suggest that self-reported and performance-based assessments of disability are influenced by different patient characteristics. In particular, it appears self-reported measures of disability are more influenced by the patient’s psychological status than performance-based measures of disability