De correlatie tussen verschillende meetschalen voor loopstoornissen bij progressieve MS

Background: walking problems are a main clinical feature of patients with progressive MS. The 12-item Multiple Sclerosis Walking Scale (MSWS-12) is a relatively new, self-rated measure of walking ability. Question is if it is equally informative as clinical assessment by the Expanded Disability Status Scale (EDSS) and the Timed Walk Test (TWT). Objective: to compare the Multiple Sclerosis Walking Scale-12 (MSWS-12) based on patient self-report upon walking ability, with both neurologist rating of neurologic examination abnormalities using the Expanded Disability Status Scale (EDSS) including measuring the maximum walking distance and observations of walking problems on the Timed Walk Test (TWT). Method: 120 progressive MS patients (PPMS/SPMS) were recruited. Walking problems were assessed using MSWS-12, EDSS and TWT. Cross-sectional correlations between MSWS-12, EDSS and TWT were calculated for the total population, MS phenotypes, gender, and two disability strata (EDSS≤4,5 and EDSS ≥ 5). The strength of correlation was labelled as follows: correlations ≤0,4 as weak to marginal; 0,4-0,6 as moderate; 0,6-0,8 as good and ≥0,8 as excellent. Results: for the total population good correlations were found between MWSW and EDSS (r=0,72) and between MSWS and TWT (r=0,73). Good correlations between this tests were also found for the different MS phenotypes, men, women and patients with EDSS≥5,0 (PPMS r=0,69 and r=0,72, SPMS r=0,78 and r=0,73, men r=0,67 and r=0,71, women r=0,76 and r=0,76, EDSS≥5,0 r=0,60 and r=0,65). Patients with an EDSS≤4,5 had only moderate correlations between MSWS and EDSS and MSWS and TWT (r=0,57 and r=0,58). For the total population excellent correlations were found between EDSS and TWT (r=0,90). Excellent correlations between those tests were also found for different MS phenotypes, man, woman and patients with EDSS≥5,0 (PPMS r=0,88, SPMS r=0,92, men r=0,90, women r=0,91, EDSS≥5,0 r=0,88). Patients with an EDSS≤4,5 had only moderate correlations between EDSS and TWT. Conclusion: Patients self-report upon MS related walking problems (MSWS-12) correlates well with results of physical examination (EDSS) including the maximum walking distance and functional testing of walking (TWT). Exceptions are patients with relatively limited walking problems EDSS≤4,5. Because of that, for patients with relatively extensive walking problems (EDSS≥5,0), MSWS-12 can offer a valuable way to measure the impact of MS on walking ability.