Repeated verum but not placebo acupuncture normalizes connectivity in brain regions dysregulated in chronic pain.

Natalia Egorova,Randy L Gollub,Jian Kong

doi:10.1016/j.nicl.2015.09.012

Natalia Egorova, Randy L Gollub + Show 1 more

Open Access

https://doi.org/10.1016/j.nicl.2015.09.012

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Abstract

Acupuncture, an ancient East Asian therapy, is aimed at rectifying the imbalance within the body caused by disease. Studies evaluating the efficacy of acupuncture with neuroimaging tend to concentrate on brain regions within the pain matrix, associated with acute pain. We, however, focused on the effect of repeated acupuncture treatment specifically on brain regions known to support functions dysregulated in chronic pain disorders. Transition to chronic pain is associated with increased attention to pain, emotional rumination, nociceptive memory and avoidance learning, resulting in brain connectivity changes, specifically affecting the periaqueductal gray (PAG), medial frontal cortex (MFC) and bilateral hippocampus (Hpc). We demonstrate that the PAG–MFC and PAG–Hpc connectivity in patients with chronic pain due to knee osteoarthritis indeed correlates with clinical severity scores and further show that verum acupuncture-induced improvement in pain scores (compared to sham) is related to the modulation of PAG–MFC and PAG–Hpc connectivity in the predicted direction. This study shows that repeated verum acupuncture might act by restoring the balance in the connectivity of the key pain brain regions, altering pain-related attention and memory.

Highlights

In recent years, acupuncture has gained popularity in Western medicine in part due to successful treatment of chronic pain (White, 2009)
In this study we examined the relationship between chronic knee osteoarthritis symptoms (measured with the Knee injury and Osteoarthritis Outcome Score (KOOS) pain and sport subscales) and resting state connectivity between periaqueductal gray (PAG)–medial frontal cortex (MFC) and PAG–Hpc, as both MFC and Hpc are crucial for pain learning, attention and memory
We found that PAG–Hpc connectivity was negatively correlated with baseline KOOS pain scores and that it decreased following repeated verum acupuncture resulting in pain score improvement

Summary

Introduction

Acupuncture has gained popularity in Western medicine in part due to successful treatment of chronic pain (White, 2009). Despite its increasingly widespread use by the general population, clinical trials evaluating the efficacy of acupuncture report inconsistent results. Often they show the general advantage of acupuncture over other physical interventions (Corbett et al, 2013; Manyanga et al, 2014; Vickers and Linde, 2014). The lack of understanding of the underlying mechanisms of acupuncture and reported cases of a failure to elicit greater clinical improvement compared to sham acupuncture (Hinman et al, 2014; Kong et al, 2013; Langevin et al, 2011), have hampered incorporation of this treatment modality into mainstream medical practice.

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