Comparison of proprioceptive reweighting in middle-aged patients with chronic low back pain and healthy people: a cross-sectional study

Abstract

Introduction: Young patients with chronic low back pain (CLBP) show reduced reliance on lumbar proprioceptive signals for balance control as compared to asymptomatic individuals. However, it remains unclear if deficits in lumbar proprioception/repositioning sense exist in middle-aged patients with CLBP. Materials and Methods: Individuals with (n=78) and without CLBP (n=73) underwent postural sway tests on a force-plate with or without a foam while bilateral L5/S1 multifidi and bilateral calves were vibrated separately. Sagittal displacements of the centre of pressure (COP) before and after vibration were recorded. Proprioception reweighting ability was estimated by the relative proprioceptive reweighting (RPW). RPW was the ratio of absolute value of COP displacement (AVCOP) during calf vibration to the sum of AVCOPs of multifidi and calves during respective vibrations. Higher PRW values indicate less reliance on lumbar multifidus proprioceptive signals for balance. Participants also underwent lumbar repositioning tests in sitting by reproducing target lumbar flexion/extension positions. The repositioning error (RE) was analysed. Between-group differences were compared. Results: Young CLBP patients demonstrated significantly higher RPW than age-matched asymptomatic controls. However, no between-group difference in RPW was noted in middle-aged people. Similarly, no between-group difference in RE was noted in all groups. RPW values were unrelated to RE in all groups. Discussion and Conclusion: While young patients with CLBP relied less on lumbar proprioception for balance, both middle-aged individuals with and without CLBP showed decreased reliance on lumbar proprioception for balance control. The decrease reliance on lumbar proprioception in middle-aged people may indicate age-related deterioration in trunk proprioception.