The relationship between pain, neuropsychological performance, and physical function in community-dwelling older adults with chronic low back pain

Objective Chronic pain and cognitive impairment are prevalent and disabling in older adults (OA), but their interrelationship has not been rigorously tested. We did so in OA with chronic low back pain (CLBP). Design A total of 323 OA (160 pain-free, 163 CLBP; mean age 73.5 years, 45% female) had neuropsychological (NP) testing with the Repeatable Battery for the Assessment of Neuropsychological Status, Trail Making Test, and the Grooved Pegboard Test. Pain intensity was measured with the McGill Pain Questionnaire Short Form. Physical performance (gait speed, functional reach, chair rise, trunk rotation, and static/dynamic lifting), psychosocial disruption (Geriatric Depression Scale, the Short Form-36 Mental Health and Role Limitations-Emotional Composite scale), and self-reported disability (Functional Status Index, the Short From-36 Physical Functioning/Role-Physical Composite scale) were also measured. Setting Outpatient research laboratory. Results There were no group differences in age, gender, or educational level, but significant differences in NP scores (P = 0.01) were found. Five scales accounted for the differences: immediate memory (P = 0.002), language (P = 0.004), delayed memory (P = 0.04), mental flexibility (Trails B [P = 0.02]), and Grooved Pegboard (P = 0.05). NP scores were significantly correlated with physical performance (R-2 = 0.30, P < 0.001), but not self-reported disability (R-2 = 0.04, P = 0.52) or psychosocial disruption (R-2 = 0.05, P = 0.46). NP function was correlated with pain intensity (R-2 = 0.17, P < 0.001), and NP function mediated the relationship between pain and physical performance. Conclusions OA with CLBP demonstrated impaired NP performance as compared with pain-free OA. Further, pain severity was inversely correlated with NP performance, and NP performance mediated the relationship between pain and physical performance. Future research should examine whether cognitive function and impaired physical performance can be improved with pain reduction.