Pain
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Randomized Controlled Trial Comparative Study
Repetitive transcranial magnetic stimulation and transcranial direct current stimulation in neuropathic pain due to radiculopathy : a randomized sham controlled comparative study.
No study has directly compared the effectiveness of repetitive transcranial magnetic stimulation (rTMS) and transcranial direct-current stimulation (tDCS) in neuropathic pain (NP). In this 2-centre randomised double-blind sham-controlled study, we compared the efficacy of 10-Hz rTMS and anodal 2-mA tDCS of the motor cortex and sham stimulation contralateral to the painful area (3 daily sessions) in patients with NP due to lumbosacral radiculopathy. Average pain intensity (primary outcome) was evaluated after each session and 5 days later. ⋯ Repetitive transcranial magnetic stimulation lowered cold pain thresholds (P = 0.04) and its effect on cold pain was correlated with its analgesic efficacy (P = 0.006). However, rTMS had no impact on individual neuropathic symptoms. Thus, rTMS is more effective than tDCS and sham in patients with NP due to lumbosacral radiculopathy and may modulate the sensory and affective dimensions of pain.
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Chronic pain in childhood and adolescence has been shown to heighten the risk for depressive and anxiety disorders in specific samples in adulthood; however, little is known about the association between a wider variety of chronic pains and internalizing mental health disorders. Using nationally representative data, the objectives of this study were to establish prevalence rates of internalizing mental health disorders (anxiety and depressive disorders) among cohorts with or without adolescent chronic pain, and to examine whether chronic pain in adolescence is associated with lifetime history of internalizing mental health disorders reported in adulthood. ⋯ Multivariate logistic regression confirmed that chronic pain in adolescence was associated with an increased likelihood of lifetime history of anxiety disorders (odds ratio: 1.33; 95% confidence interval: 1.09-1.63, P = 0.005) and depressive disorders (odds ratio: 1.38; confidence interval: 1.16-1.64, P < 0.001) reported in adulthood. Future research is needed to examine neurobiological and psychological mechanisms underlying these comorbidities.
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Randomized Controlled Trial
A randomized, double blind, placebo controlled trial of injected capsaicin for pain in Morton's neuroma.
Intermetatarsal neuroma or Morton's neuroma is a painful condition of the foot resulting from an entrapment of the common digital nerve typically in the third intermetatarsal space. The pain can be severe and especially problematic with walking. Treatment options are limited and surgery may lead to permanent numbness in the toes. ⋯ A trend toward significance was noted at weeks 2 and 3. Improvements in functional interference scores and reductions in oral analgesic use were also seen in the capsaicin-treated group. These findings suggest that injection of capsaicin is an efficacious treatment option for patients with painful intermetatarsal neuroma.
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Patients' expectations are important predictors of the outcome of analgesic treatments, as demonstrated predominantly in research on placebo effects. Three commonly investigated interventions that have been found to induce expectations (verbal suggestion, conditioning, and mental imagery) entail promising, brief, and easy-to-implement adjunctive procedures for optimizing the effectiveness of analgesic treatments. However, evidence for their efficacy stems mostly from research on experimentally evoked pain in healthy samples, and these findings might not be directly transferable to clinical populations. ⋯ Overall, a medium-sized effect of the interventions on patients' pain relief was observed (Hedges g = 0.61, I = 73%), with varying effects of verbal suggestion (k = 18, g = 0.75), conditioning (always paired with verbal suggestion, k = 3, g = 0.65), and imagery (k = 6, g = 0.27). Subset analyses indicated medium to large effects on experimental and acute procedural pain and small effects on chronic pain. In conclusion, patients' pain can be relieved with expectation interventions; particularly, verbal suggestion for acute procedural pain was found to be effective.
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Meta Analysis
Brain activations during pain: a neuroimaging meta-analysis of pain patients and healthy controls.
In response to recent publications from pain neuroimaging experiments, there has been a debate about the existence of a primary pain region in the brain. Yet, there are few meta-analyses providing assessments of the minimum cerebral denominators of pain. Here, we used a statistical meta-analysis method, called activation likelihood estimation, to define (1) core brain regions activated by pain per se, irrelevant of pain modality, paradigm, or participants and (2) activation likelihood estimation commonalities and differences between patients with chronic pain and healthy individuals. ⋯ Common activations for healthy subjects and patients with pain alike included the thalamus, ACC, insula, and cerebellum. A comparative analysis revealed that healthy individuals were more likely to activate the cingulum, thalamus, and insula. Our results point toward the central role of the insular cortex and ACC in pain processing, irrelevant of modality, body part, or clinical experience; thus, furthering the importance of ACC and insular activation as key regions for the human experience of pain.