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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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.
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Randomized Controlled Trial
Problem Solving Skills Training for Parents of Children with Chronic Pain: A Pilot Randomized Controlled Trial.
This pilot randomized controlled trial aimed to determine the feasibility, acceptability, and preliminary efficacy of parental problem-solving skills training (PSST) compared with treatment as usual on improving parental mental health symptoms, physical health and well-being, and parenting behaviors. Effects of parent PSST on child outcomes (pain, emotional, and physical functioning) were also examined. Participants included 61 parents of children aged 10 to 17 years with chronic pain randomized to PSST (n = 31) or treatment as usual (n = 30) groups. ⋯ Findings demonstrate that PSST is feasible and acceptable to parents of youths with chronic pain. Treatment outcome analyses show promising but mixed patterns of effects of PSST on parent and child mental health outcomes. Further rigorous trials of PSST are needed to extend these pilot results.
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We developed the Michigan Body Map (MBM) as a self-report measure to assess body areas where chronic pain is experienced and to specifically quantify the degree of widespread body pain when assessing for centralized pain features (eg, fibromyalgia-like presentation). A total of 402 patients completed the measure in 5 distinct studies to support the validation of the original and a revised version of the MBM. Administration is rapid 39 to 44 seconds, and errors for the original MBM were detected in only 7.2% of the possible body areas. ⋯ Furthermore, the revised MBM showed convergent and discriminant validity with other self-report measures of pain, mood, and function. In conclusion, the MBM demonstrated utility, reliability, and construct validity. This new measure can be used to accurately assess the distribution of pain or widespread bodily pain as an element of the fibromyalgia survey score.
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Plasticity in inhibitory receptors, neurotransmission, and networks is an important mechanism for nociceptive signal amplification in the spinal dorsal horn. We studied potential changes in GABAergic pharmacology and its underlying mechanisms in hyperalgesic priming, a model of the transition from acute to chronic pain. We find that while GABAA agonists and positive allosteric modulators reduce mechanical hypersensitivity to an acute insult, they fail to do so during the maintenance phase of hyperalgesic priming. ⋯ Neurolide 2 treatment also reverses the change in polarity in GABAergic pharmacology observed in the maintenance of hyperalgesic priming. We propose that increased nlgn2 expression is associated with hyperalgesic priming where it promotes dysregulation of inhibitory networks. Our observations reveal new mechanisms involved in the spinal maintenance of a pain plasticity and further suggest that disinhibitory mechanisms are central features of neuroplasticity in the spinal dorsal horn.