A 30-METER WALKING TEST AS A MEASURE OF CERVICAL SPONDYLOTIC MYELOPATHY SEVERITY: TEST CHARACTERISTICS AND RESULTS FROM TWO MULTICENTER COHORT STUDIES

Abstract

Background Context: Cervical Spondylotic Myelopathy (CSM) is a progressive, degenerative condition and the most common cause of spinal cord dysfunction worldwide. A timed 30-meter walking test (30MWT) has previously been recommended for testing disease severity in patients with CSM because of its objectivity, quantitative nature, and ease of administration. However, very little has been reported in the literature regarding its use. Study Design/Setting: We utilized data from two prospective CSM cohort studies to analyze properties of the 30MWT test for patients with CSM. All patients had symptomatic CSM and subsequently underwent surgical decompression. Each patient completed 3 trials of the 30MWT at baseline as well as 6, 12, and 24 months following surgery. Methods: Repeated measures analysis of variance (ANOVA) was used to examine test reproducibility, and Spearman’s correlation coefficients were used to compare the results of the 30MWT to other validated scales used in the CSM population. Additionally, we used paired T-tests to assess the difference between baseline and 6-month post-operative 30MWT times. Standardized response mean was used to measure responsiveness. Results: Moderate correlation (-0.551) was seen between the 30MWT and the modified Japanese Orthopedic Association (mJOA) scale as well as the Nurick score (0.468) at baseline. Low correlation was found between the 30MWT and the NDI (0.253) as well as the physical component of the Short-Form 36 Health Survey (-0.380). Walking time did not vary significantly between the three trials at baseline (p = 0.66). At 6 months post-op, patients completed the 30MWT 9.9 seconds faster compared to baseline (p < 0.0001). Conclusions: The results from two prospective cohort studies demonstrate that the 30MWT is reproducible and moderately correlated with other validated scales used with CSM patients. Because the 30MWT is simple, quick, affordable, and assess gait parameters not accurately assessed by other standard metrics, it should be used as an ancillary test for CSM patients.