Neuroimaging Approaches to Deconstructing Acupuncuture for Chronic Pain

最近对针灸治疗慢性疼痛的几项荟萃分析表明，真针灸并不优于假针灸/安慰剂针灸。然而，这些相同的荟萃分析也注意到不同试验中针灸方法的显着异质性，这使得合并结果变得复杂。例如，虽然电针（EA）在缓解纤维肌痛（FM）疼痛方面优于假针灸，但手工针灸（MA）则不然。就生理作用而言，EA 和 MA 是非常不同的程序。它们影响不同的外周目标并引起不同的心理物理感知，体现在不同的大脑反应中。事实上，体感传入可能是针刺镇痛的一个关键变量，并且一些假针装置（例如Streitberger针（SN））的使用也受到批评，因为它们也会产生体感。此外，躯体感觉对于 FM 来说可能是一个特别重要的变量，因为众所周知，这种慢性疼痛疾病会表现出感觉和伤害性放大的改变。因此，我们假设 EA 对 FM 更有效，因为它作为一种脱敏疗法，在多个治疗过程中重复应用时，逐渐使神经系统习惯于持续的内源性疼痛和体感信号传导。我们的总体目标是评估针灸诱导的体感传入对 FM 神经生物学和镇痛改变的影响。为了检验我们的假设，我们将把神经影像学纳入一项随机、盲法、纵向的 FM 试验中，使用具有显着不同体感传入量的针灸干预措施：(1) EA 和 (2) 模拟激光 (ML) 针灸 - 一种相对较新的假针灸形式，不会引起任何体感传入。我们的第一个目标将在基线上表征 FM 慢性疼痛中体感相关神经回路的改变。目标 2 将评估电针和模拟激光针灸对 FM 慢性疼痛神经回路的纵向脱敏作用。然后，目标 3 将评估基线神经回路改变的能力，以预测对电针和模拟激光针灸的临床反应。这些分析将提供急需的信息，说明哪些患者可能从哪些针灸干预措施中受益最大。

Several recent meta-analyses of acupuncture for chronic pain have shown that verum acupuncture is not superior to sham/placebo acupuncture. However, these same meta-analyses have also noted significant heterogeneity in acupuncture methods across trials, which complicates combining results. For example, while electro-acupuncture (EA) was superior to sham acupuncture in relieving pain for fibromyalgia (FM), manual acupuncture (MA) was not. In terms of physiologic action, EA and MA are very different procedures. They effect different peripheral targets and induce different psychophysical perceptions, manifest in different brain response. In fact, somatosensory afference may be a key variable in acupuncture analgesia, and the use of some sham needling devices (e.g. Streitberger Needle (SN)) has been criticized since they also produce somatosensation. Moreover, somatosensation may be a particularly important variable for FM, as this chronic pain disorder is known to display altered sensory and nociceptive amplification. Thus, we hypothesize that EA has been more effective for FM because it functions as a desensitization therapy, which when applied repeatedly over multiple treatment sessions, gradually habituates the nervous system to continuing endogenous pain and somatosensory signaling. Our overall goal is to evaluate the impact of acupuncture-induced somatosensory afference on altered neurobiology and analgesia in FM. To test our hypotheses, we will incorporate neuroimaging into a randomized, blinded, longitudinal trial in FM using acupuncture interventions with significantly different amounts of somatosensory afference: (1) EA and (2) mock laser (ML) acupuncture - a relatively new form of sham acupuncture that does not induce any somatosensory afference. Our first Aim will characterize, at baseline, the altered somatosensory-related neurocircuitry underlying chronic pain in FM. Aim 2 will evaluate longitudinal desensitization effects of electro- and mock laser acupuncture on the neurocircuitry underlying chronic pain in FM. Aim 3 will then evaluate the ability of altered neurocircuitry at baseline to predict clinical response to both electro- and mock laser acupuncture. These analyses will provide much needed information about which patients might benefit most from which acupuncture interventions.