Cortical activity during cognitive and walking tasks in individuals with chronic nonspecific low back pain: a functional near-infrared spectroscopy study

Introduction Previous research demonstrates that individuals with chronic nonspecific low back pain (CNSLBP) exhibit changes of gait patterns. However, the neural mechanisms responsible for these adverse events remain unelucidated. In this study, we used functional near-infrared spectroscopy (fNIRS) to investigate cortical activities during cognitive and walking tasks to provide evidence of the central mechanisms responsible for changes of gait patterns in individuals with CNSLBP. Methods In this cross-sectional study, we evaluated 18 individuals with CNSLBP (the CNSLBP group) and 18 healthy controls (the HC group) under three specific conditions: Task 1 (a single walking task), Task 2 (a single cognitive task) and Task 3 (a cognitive-walking dual task). Cortical activities were measured using fNIRS, including the bilateral premotor cortex and supplementary motor area (PMC/SMA), primary motor cortex (M1), somatosensory association cortex (SAC), and primary somatosensory cortex (S1). Gait parameters, including step duration, step length, stride length, velocity, cadence, swing power, and cycle, were measured using a three-dimensional gait analysis system. Results In Task 1, the CNSLBP group exhibited a significantly lower velocity ( p = 0.029) and higher activation in the left SAC ( p = 0.001) and right S1 ( p = 0.018) than that of the HC group. In Task 2, the CNSLBP group exhibited higher activation in the left SAC ( p = 0.028), right SAC ( p = 0.033), and left S1 ( p = 0.032). In Task 3, the CNSLBP group exhibited significantly lower step length ( p = 0.031), stride length ( p = 0.041), velocity ( p = 0.016), and swing power ( p = 0.047). Correlation analysis in Task 1 revealed stronger associations between parameters in the CNSLBP group. Conclusion Our findings suggest that individuals with CNSLBP exhibit distinct patterns of cortical activities and gait performance. The SAC and S1 were involved in walking, and central sensitization was observed in individuals with CNSLBP in daily cognitive and walking tasks. These findings could contribute to the recovery and rehabilitation of CNSLBP.