Pain
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Meta Analysis
A systematic review with meta-analyses of the association between stigma and chronic pain outcomes.
Stigma is common in people experiencing chronic pain and there are indications that it may adversely affect pain outcomes. However, to date, there is no systematic review exploring the impact of stigma on chronic pain-related outcomes. This systematic review and meta-analysis aimed to examine the association between stigma and key chronic pain outcomes and differences in stigma between pain conditions. ⋯ Data from 2 prospective studies and those only reporting multivariate analyses that were not included in meta-analyses further supported these findings. There was some evidence that individuals who experience pain conditions with less clear pathophysiology may report greater stigma, although more research is needed. The review highlights that there is a growing number of studies on stigma in the pain field showing an adverse association between stigma and chronic pain outcomes.
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Meta Analysis
The effect of unpredictability on the perception of pain: a systematic review and meta-analysis.
Despite being widely assumed, the worsening impact of unpredictability on pain perception remains unclear because of conflicting empirical evidence, and a lack of systematic integration of past research findings. To fill this gap, we conducted a systematic review and meta-analysis focusing on the effect of unpredictability on pain perception. We also conducted meta-regression analyses to examine the moderating effect of several moderators associated with pain and unpredictability: stimulus duration, calibrated stimulus pain intensity, pain intensity expectation, controllability, anticipation delay, state and trait negative affectivity, sex/gender and age of the participants, type of unpredictability (intensity, onset, duration, location), and method of pain induction (thermal, electrical, mechanical pressure, mechanical distention). ⋯ However, several significant moderators were found, ie, targeted stimulus pain intensity, expected pain intensity, and state negative affectivity. Trait negative affectivity and uncontrollability showed no significant effect, presumably because of the low number of included studies. Thus, further investigation is necessary to clearly determine their role in unpredictable pain perception.
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Botulinum toxin (BoNT), a presynaptic inhibitor of acetylcholine (Ach) release at the neuromuscular junction (NMJ), is a successful and safe drug for the treatment of several neurological disorders. However, a wide and recent literature review has demonstrated that BoNT exerts its effects not only at the "periphery" but also within the central nervous system (CNS). Studies from animal models, in fact, have shown a retrograde transport to the CNS, thus modulating synaptic function. ⋯ In this new light, BoNT might interfere with the activity of spinal, brain stem, and cortical circuitry, modulating excitability and the functional organization of CNS in healthy conditions. Botulinum toxins efficacy on CNP is the result of a wide and complex action on many and diverse mechanisms at the basis of the maladaptive plasticity, the core of the pathogenesis of CNP. This systematic review aims to discuss in detail the BoNT's mechanisms and effects on peripheral and central neuroplasticity, at the basis for the clinical efficacy in CNP syndromes.