Reliability of posturographic measurements in the assessment of impaired sensorimotor function in chronic low back pain

Abstract

The evaluation of postural stability using posturography could be both a valuable functional diagnostic and treatment outcome monitoring tool in rehabilitation practice of patients with chronic low back pain (cLBP). No evidence, however, seems to exist, whether or not such posturographic measures are reliable in these patients and therefore clinically and scientifically useful. The aims of this study were manifold and aimed at investigating (1) differences of posturographic measures between cLBP patients and healthy controls (HCs), (2) short- (intrasession-) and long-term (intersession-) reliability of these measurements, and (3) the relationship between both pain intensity and test-related feelings and significant learning effects of the posturographic measures in cLBP. A total of 32 cLBP patients and 19 non-sportive HCs completed (1) comprehensive clinical examination, (2) quantitative posturographic testing (SMART EquiTest, Neurocom International, Clackamas, Oregon) that included all the sensory organisation test (SOT), the motor control test (MCT) and the adaptation test (ADT) and (3) psychological ratings of pain as well as posturographic test related personal feelings and fear associated beliefs. Of these, 22 cLBP patients who received no therapy repeated all measurements and examinations on a second day, 2–3 weeks later. Results revealed significant differences between cLBP patients and HCs in the more demanding postural test conditions of the SOT and the SOT composite score only. Intra-session reliability testing demonstrated significant improvements of the SOT and ADT measures for both HCs and cLBP patients. Results of long-term reliability testing showed significant improvements of the more challenging SOT conditions and SOT composite score. VAS ratings of pain, feelings and fear associated beliefs were not associated with such longitudinal changes. Conclusion Our findings suggest that the significant learning effects observed for the SOT conditions may limit the clinical application of SMART EquiTest postural stability measures for cLBP patients in rehabilitation everyday practice. Further development in software processing will be necessary to identify new postural parameters that are less prone to learning effects.