Abstract
Purpose: Self reported walking distance is a clinically relevant measure of function, our aim was to report patient accuracy and understand factors that might influence perceived walking distance.
Method: A prospective cohort study. 103 patients were asked to perform one test of distance estimation and 2 tests of functional distance perception using pre-measured landmarks. Standard spine specific outcomes included the patient reported claudication distance, Oswestry disability index (ODI), Low Back Outcome Score (LBOS), visual analogue score (VAS) for leg and back, and other measures.
Results: There are over-estimators and under-estimators. Overall the accuracy to within 10 yards was only 5% for distance estimation and 40% for the two tests of functional distance perception. Distance: Actual distance 121.4 yds; mean response 268yds (95% CI 192.8–344.15), Functional test 1 actual distance 32 yards; mean response 78.4 yds (95% CI 58.6–97.3) Functional test 2 actual distance 21.4yds; mean response 51.9yds (95% CI 38.3–65.5). Surprisingly patients over 60 years of age (n=43) are twice as accurate with each test performed compared to those under 60 (n=60) (average 70% overestimation compared to 140%; p=0.06). Patients in social class I (n=18) were more accurate than those in classes II–V (n= 85): There was a positive correlation between poor accuracy and increasing MZD (Pearson’s correlation coefficient 0.250; p=0.012). ODI, LBOS and other parameters measured showed no correlation.
Conclusions: Subjective distance perception and estimation is poor in this population. Patients over 60 and those with a professional background are more accurate.
Ethics approval: not required
Interest Statement: none
Correspondence should be addressed to BASS/BCSS c/o BOA, at the Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London, WC2A 3PE, England.
