Functional brain mapping in patients with chronic back pain shows age-related differences.

ABSTRACT Low back-pain is the most common pain condition and cause for disability in older adults. Older adults suffering from low-back pain are more disabled than their healthy peers, are more predisposed to frailty, and tend to be undertreated. The cause of increased prevalence and severity of this chronic pain condition in older adults is unknown. Here we draw on accumulating data demonstrating a critical role for brain limbic and sensory circuitries in the emergence and experience of chronic low-back pain (CLBP) and the availability of resting state brain activity data collected at different sites to study how brain activity patterns predictive of CLBP differ between age groups. We apply a data driven multivariate searchlight analysis to amplitude of low-frequency fluctuation brain maps to classify CLBP patients with > 70% accuracy. We observe that brain activity pattern including the paracingulate gyrus, insula/SII, inferior frontal, temporal, and fusiform gyrus predicted CLBP. When separated by age groups, brain patterns predictive of older CLBP patients showed extensive involvement of limbic brain areas including the ventro-medial prefrontal cortex, the nucleus accumbens and hippocampus, whereas only anterior insula paracingulate and fusiform gyrus predicted CLBP in the younger patients. In addition, we validated the relationships between back-pain intensity ratings and CLBP brain activity patterns in an independent data set not included in our initial patterns' identification. Our results are the first to directly address how aging affects the neural signature of CLBP and point to an increased role of limbic brain areas in older CLBP patients.