Diffusion tensor imaging of white matter integrity and pain-related outcomes in chronic nonspecific neck pain.

Chronic neck pain is associated with neuroplastic changes in brain structure, but its alterations in white matter integrity remain unclear. This study aimed to investigate white matter microstructural changes in patients with chronic nonspecific neck pain and their relationships with pain-related outcomes (i.e., pain duration, intensity, disability, extent and pressure pain thresholds (PPTs) over the neck). Using diffusion tensor imaging, fractional anisotropy (FA) and mean diffusivity (MD) were analyzed in 30 individuals with neck pain and 30 pain-free controls through whole-brain and region-of-interest (ROI) approaches. The results revealed that individuals with neck pain had lower FA and higher MD in several white matter tracts related to pain processing (e.g., corpus callosum, internal capsule, superior longitudinal fasciculus and superior corona radiata) compared to controls (adjusted-p values < 0.05). In specific ROIs, FA was negatively correlated with pain intensity, disability, extent and PPTs (r=-0.50 to -0.60, adjusted-p values < 0.05) while MD was positively correlated with pain duration, disability and extent (r = 0.54 to 0.59, adjusted-p values < 0.05). These results suggest widespread white matter alterations in people with chronic nonspecific neck pain, providing insights into altered central mechanisms that may contribute to pain persistence. However, the results should be interpreted with caution given the limitations of data acquisition.