An objective approach to quantifying pain behavior and gait patterns in low back pain patients.

Patterns of walking and concomitant pain behavior were compared in a group of chronic low back patients (n = 18) and normal controls (n = 18). Subjects were asked to walk a 5 m course. A transducer placed in the subjects' shoes produced a force proportional signal that permitted measurement of walking parameters. Subjects were videotaped in order to record the occurrence of 5 specific pain behaviors: guarding, bracing, rubbing the painful area, grimacing, and sighing. Data analysis revealed significant differences in walking patterns of the patients and controls. Patients walked more slowly, took shorter steps and did not show the symmetrical gait patterns evident in normal controls. Patients also exhibited much higher levels of pain behavior. The gait of patients receiving disability payments or taking narcotics differed significantly from those who were not. Patients receiving disability payments had significantly longer stride lengths and swing time than patients not receiving disability/financial compensation payments. Patients taking narcotics showed longer single limb support time for the left leg than those who were not. By combining objective measures of gait and motor pain behaviors, clinicians and researchers may be able to more objectively evaluate factors that may affect patient behavior and measure the effects of interventions designed to modify behavior.