Reduced tactile acuity in chronic low back pain is linked with structural neuroplasticity in primary somatosensory cortex and is modulated by acupuncture therapy
Kristen Sparrow • May 16, 2020
This new article by friend of blog Vitaly Napadow shows improved tactile acuity after treatment with acupuncture for Low Back Pain. This is significant because
“Previous neuroimaging studies have shown that other chronic pain disorders also demonstrate altered brain structure in S1, as well as other pain-related brain areas (As-Sanie et al., 2012, Kong et al., 2013, Kregel et al., 2015, Ung et al., 2014). Following acupuncture, such maladaptive neuroplasticity showed improvement, and was linked with improved pain and/or peripheral nerve conduction latency (Napadow et al., 2007, Maeda et al., 2017). Although acupuncture-induced neuroplasticity had been reported for neuropathic pain disorders such as carpal tunnel syndrome, similar outcomes have not been reported for cLBP.”
So this study shows that there are verified changes in the brain and in sensation after real acupuncture but not with sham acupuncture. Note: I’m surprised that Kapchuk is on this paper since he has repeatedly said that acupuncture effectiveness is highly correlated with the practioner and largely placebo.
Reduced tactile acuity in chronic low back pain is linked with structural neuroplasticity in primary somatosensory cortex and is modulated by acupuncture therapy
Abstract
Prior studies have shown that patients suffering from chronic Low Back Pain (cLBP) have impaired somatosensory processing including reduced tactile acuity, i.e. reduced ability to resolve fine spatial details with the perception of touch. The central mechanism(s) underlying reduced tactile acuity are unknown but may include changes in specific brain circuitries (e.g. neuroplasticity in primary somatosensory cortex, S1). Furthermore, little is known about the linkage between changes in tactile acuity and the amelioration of cLBP by somatically-directed therapeutic interventions, such as acupuncture. In this longitudinal neuroimaging study, we evaluated healthy control adults (HC, N=50) and a large sample of cLBP patients (N=102) with structural brain imaging (T1-weighted MRI for Voxel Based Morphometry, VBM; Diffusion Tensor Imaging, DTI) and tactile acuity testing using two-point discrimination threshold (2PDT) over the lower back (site of pain) and finger (control) locations. Patients were evaluated at baseline and following a 4-week course of acupuncture, with patients randomized to either verum acupuncture, two different forms of sham acupuncture (designed with or without somatosensory afference), or no-intervention usual care control. At baseline, cLBP patients demonstrated reduced acuity (greater 2PDT, P=0.01) over the low back, but not finger (P=0.29) locations compared to HC, suggesting that chronic pain affects tactile acuity specifically at body regions encoding the experience of clinical pain. At baseline, Gray Matter Volume (GMV) was elevated and Fractional Anisotropy (FA) was reduced, respectively, in the S1-back region of cLBP patients compared to controls (P<0.05). GMV in cLBP correlated with greater 2PDT-back scores (ρ=0.27, P=0.02). Following verum acupuncture, tactile acuity over the back was improved (reduced 2PDT) and greater improvements were associated with reduced S1-back GMV (ρ=0.52, P=0.03) and increased S1-back adjacent white matter FA (ρ=-0.56, P=0.01). These associations were not seen for non-verum control interventions. Thus, S1 neuroplasticity in cLBP is linked with deficits in tactile acuity and, following acupuncture therapy, may represent early mechanistic changes in somatosensory processing that track with improved tactile acuity.
Keywords
