Structural brain alterations and clinical associations in individuals with chronic nonspecific neck pain

Chronic pain is associated with changes in brain structures. However, the specific morphological changes in chronic nonspecific neck pain (CNSNP) are still unclear.

To investigate altered brain morphology in patients with CNSNP and its relationships with clinical characteristics of neck pain.

Cross-sectional study.

Thirty CNSNP and 30 controls underwent T1-weighted structural MRI to assess whole-brain vertex-wise cortical thickness and gray matter volume. Between-group differences were determined using cluster-wise correction for multiple comparisons and analyses of global structure and pain-related regions of interest (ROIs). Pain outcomes were neck pain duration, intensity, disability and pressure pain thresholds (PPTs) over the cervical spine.

Overall, the cluster-wise analysis revealed increased cortical thickness and decreased gray matter volume in several brain regions such as the precuneus, supramarginal gyrus and parietal cortex in the neck pain group (CWP<0.05). The global analysis showed that the neck pain group had increased total thickness and decreased total volume (p < 0.05). The ROI analysis showed that the neck pain group exhibited increased thickness in the primary somatosensory cortex (S1), anterior cingulate cortex (ACC) and precuneus and decreased volume in the prefrontal cortex (PFC), S1, ACC and insula compared to controls (adjusted p-values<0.05). Reduced insula volume correlated with greater neck disability (r = -0.53, adjusted p-value<0.01). Increased PPTs correlated with greater S1 and precuneus thickness (r = 0.46-0.48, adjusted p-values<0.05) and S1 volume (r = 0.53-0.58, adjusted p-values<0.05).

Patients with CNSNP exhibited increased cortical thickness and decreased gray matter volume in brain regions involved in pain processing and emotional and cognitive responses.