Middle cingulate cortex function contributes to response to non-steroidal anti-inflammatory drug in cervical...

Cervical spondylosis (CS) is often accompanied by persistent cervical pain, and psychological complications including depression and anxiety, which aggravate pain. Past studies have revealed brain alterations in chronic pain patients. However, the cortical mechanism for NSAID (non-steroidal anti-inflammatory drug) responders relative to non-responders is still lacking. Therefore, we aimed to investigate the brain functional differences between responders to NSAID relative to non-responders using amplitude of low-frequency fluctuation (ALFF) and dynamic functional connectivity variance (DFCV). To our knowledge, our study is the first to investigate the DFCV in CS patients.

We first explored the differences in psychological inventories in CS patients who respond to NSAID vs non-responders. The voxel-wise ALFF was calculated and compared between CS patients and healthy controls. The ALFF within the resultant clusters were extracted and compared between responders and non-responders. DFCV among the resulting clusters was compared in responders vs non-responders.

We found that (1) compared to responders, non-responders exhibited higher levels of anxiety and depression; (2) relative to healthy controls, CS patients exhibited altered ALFF within the middle cingulate cortice (MCC), cerebellum, and middle frontal gyrus (MFG); (3) moreover, compared with responders, non-responders exhibited lower ALFF within MCC; furthermore, non-responders also exhibited increased DFCV between MCC and cerebellum, and between MCC and MFG.

Our data indicate that psychological comorbidities (e.g., anxiety) influence response to NSAID in CS patients. Relative to NSAID responders, non-responders had altered MCC function, which may be associated with anxiety in CS patients.