Brain activation is correlated with patient-reported outcomes in patients with chronic lower back pain: a prospective observational study in Japan.

Abstract

This was a prospective observational study. This study aimed to investigate the relationship between brain activity and self-reported outcomes in patients with chronic lower back pain (CLBP). Previous research has shown that emotional brain regions, including the amygdala, are activated in patients with CLBP in response to pain-related stimuli. However, their association with patient-reported outcomes has been unclear. In this study, 20 patients with CLBP and 20 age- and sex-matched healthy controls underwent functional magnetic resonance imaging during verbal stimulation involving pain-related and neutral words. Brain activation was analyzed in predefined regions of interest, including the amygdala. The associations between brain activity and clinical outcome measures (e.g., the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire [JOABPEQ], Oswestry Disability Index [ODI], Pain Catastrophizing Scale, and Hospital Anxiety and Depression Scale) were assessed. Under the pain-related versus neutral verbal contrast condition, the patients with CLBP showed a significantly greater left amygdala activation than the controls (p =0.012). In the CLBP group, left amygdala activation was positively correlated with selected JOABPEQ domain scores, including lumbar spine dysfunction, gait dysfunction, social life disorder, and psychological disorder (r =0.49-0.61), and negatively correlated with the ODI score (r =-0.49). These findings suggest that amygdala activity reflects the emotional aspects of CLBP and is associated with patient-reported functional status.