Local connectivity of the resting brain connectome in patients with low back-related leg pain: A multiscale frequency-related Kendall's coefficient of concordance and coherence-regional homogeneity study.

Fuqing Zhou,Xianjun Zeng,Lin Wu,Linghong Guo,Yong Zhang

doi:10.1016/j.nicl.2019.101661

Abstract

Increasing evidence has suggested that central plasticity plays a crucial role in the development and maintenance of (chronic) nonspecific low back pain. However, it is unclear how local or short-distance functional interactions contribute to persisting low back-related leg pain (LBLP) due to a specific condition (i.e., lumbar disc herniation). In particular, the multiscale nature of local connectivity properties in various brain regions is still unclear. Here, we used voxelwise Kendall's coefficient of concordance (KCC) and coherence (Cohe) regional homogeneity (ReHo) in the typical (0.01–0.1 Hz) and five specific frequency (slow-6 to slow-2) bands to analyze individual whole-brain resting-state functional magnetic resonance imaging scans in 25 persistent LBLP patients (duration: 36.7 ± 9.6 months) and 26 healthy control subjects. Between-group differences demonstrated significant alterations in the KCC- and Cohe- ReHo of the right cerebellum posterior lobe, brainstem, left medial prefrontal cortex and bilateral precuneus in LBLP patients in the typical and five specific frequency bands, respectively, along with interactions between disease status and the five specific frequency bands in several regions of the pain matrix and the default-mode network (P < .01, Gaussian random field theory correction). The altered ReHo in the five specific frequency bands was correlated with the duration of pain and two-point discrimination, which were assessed using partial correlational analysis. These results linked the course of disease to the local connectivity properties in specific frequency bands in persisting LBLP. In future studies exploring local connectome association in pain conditions, integrated frequency bands and analytical methods should be considered.

Highlights

Low back pain is an extremely common disorder, estimated to affect millions of individuals each year (Zhang et al, 2009)
A total of persistent low back-related leg pain (LBLP) patients and healthy controls (HCs) subjects were selected for the group regional homogeneity (ReHo) comparison
In the tactile spatial resolution ability assessment, decreased 2PD test scores in LBLP patients were observed in the right (30.60 ± 1.62 mm) and left (30.00 ± 1.17 mm) feet and the right (24.96 ± 1.22 mm) and left (26.24 ± 1.27 mm) hands, which indicated cortical reorganization of, for instance, somatosensory cortices

Summary

Introduction

Low back pain is an extremely common disorder, estimated to affect millions of individuals each year (Zhang et al, 2009). Simple mechanical problems, such as herniated nucleus pulposus and herniated disk, cannot adequately explain the clinical symptoms of LBLP patients or the possible pathogenesis of the pain. LBLP was found to be associated with increased disability and pain and poorer quality of life and recovery than patients with nonspecific low back pain (Konstantinou et al, 2013; Stynes et al, 2016). Approximately one-quarter to one-third of these LBLP patients continued to have pain after surgery (Konstantinou et al, 2015). Understanding the role of neural plasticity or rewiring of the brain in LBLP patients will improve our knowledge of pain symptoms and of the mechanisms underlying LBLP-associated central modulation

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