The Effect of Walking Distance on EDSS Score in Patients with Multiple Sclerosis

OBJECTIVE: This study aimed first to identify the range of the Expanded Disability Status Scale (EDSS) score by comparing the actual walking distance and the estimated walking distance of multiple sclerosis (MS) patients, and second, to investigate the effect of fatigue on walking distance.
METHODS: Thirty MS patients and 20 age -and gender- matched healthy volunteers were included in the study. MS patients were divided into two groups according to the EDSS score. Fatigue was measured using the Fatigue Severity Scale (FSS) and motor fatigue was measured using the 200 meter walking test. The increase in muscle tone was evaluated by Modified Ashworth Scale. The first group of MS patients and healthy control group patients were asked to estimate the distance they can walk without rest within six minutes. Then, their actual walking distance was measured for six minutes. The second group of MS patients was asked to estimate their most probable walking distance without rest; then, the actual walking distance of the patients was measured.
RESULTS: In terms of FSS values, fatigue severity was different in the two MS groups (p< 0.05). The fatigue severity of the second MS group was higher than of the first group. Walking fatigue index values were also different (p< 0.05), and the higher value was seen in the second MS group. The second group of MS patients had significantly higher spasticity for both muscles compared to the first group (p< 0.05). While estimated and actual walking distance was not found significantly different in the first MS group and control group (p> 0.05), the second MS group’s estimated and actual walking distances were significantly different (p< 0.05). A negative correlation was found between FSS scores and estimated walking distance in the second MS group (p< 0.05). A negative correlation was present between motor fatigue and actual walking distance only in the second MS group (p< 0.05).
CONCLUSION: EDSS evaluation is more reliable in patients with low level disability. The accuracy issues arise in patients with EDSS scores of 4-5. Additionally, there is an important correlation between motor fatigue and walking distance in these patients. For motor fatigue, spasticity is an important determinant.