Comparative Associations of Working Memory and Pain Catastrophizing With Chronic Low Back Pain Intensity.

Background: Because of its high global burden, determining biopsychosocial influences of chronic low back pain (CLBP) is a research priority. Psychological factors such as pain catastrophizing are well established. However, cognitive factors such as working memory warrant further investigation to be clinically useful.

Objective: The purpose of this study was to determine how working memory and pain catastrophizing are associated with CLBP measures of daily pain intensity and movement-evoked pain intensity.

Design: This study was a cross-sectional analysis of individuals with ≥3 months of CLBP (n=60) compared with pain-free controls (n=30).

Method: Participants completed measures of working memory, pain catastrophizing, and daily pain intensity. Movement-evoked pain intensity was assessed using the Back Performance Scale. Outcome measures were compared between individuals with CLBP and those who were pain-free using nonparametric testing. Associations were determined using multivariate regression analyses.

Results: Participants with CLBP (mean age=47.7 years, 68% female) had lower working memory performance (P=.008) and higher pain catastrophizing (P<.001) compared with pain-free controls (mean age=47.6 years, 63% female). For individuals with CLBP, only working memory remained associated with daily pain intensity (R(2)=.07, standardized beta=-.308, P=.041) and movement-evoked pain intensity (R(2)=.14, standardized beta=-.502, P=.001) after accounting for age, sex, education, and interactions between pain catastrophizing and working memory.

Limitations: The cross-sectional design prevented prospective analysis. Findings also are not indicative of overall working memory (eg, spatial) or cognitive performance.

Conclusion: Working memory demonstrated the strongest association with daily pain and movement-evoked pain intensity compared with (and after accounting for) established CLBP factors. Future research will elucidate the prognostic value of working memory on prevention and recovery of CLBP.