Expanded Disability Status Scale (EDSS) estimation in multiple sclerosis from posturographic data

Abstract

Expanded disability status scale (EDSS) is the most widely used clinical scale to evaluate levels of multiple sclerosis (MS). As MS can lead to disruptions in the regulation of balance and the disability can be evaluated by force platform posturography, we have developed in this study a new strategy to estimate EDSS from postural data. 118 volunteers with EDSS ranging from 0 to 4.5 participated in this study, with eyes closed. By using second-order polynomial regression models, EDSS was estimated from two postural sway parameters, respectively, the length and the surface and four recurrence quantification analysis (RQA) parameters: percentage of recurrence (%Rec), Shannon entropy (Ent), mean diagonal line length (LL) and trapping time (TT). In addition, all four RQA parameters were calculated for position, instantaneous velocity and acceleration of the center of pressure. In order to select the most accurate method for estimating EDSS, four statistical indices (percentage of agreement, underestimation and overestimation, as well as mean error) were calculated comparing clinical and estimated EDSS scores. The results demonstrate that estimations of EDSS from surface, %Rec and LL of position, best agreed with clinical scores. This study emphasizes the possibility of distinguishing EDSS scores using postural sway and RQA parameters.

Association of Postural Sway with Disability Status and Cerebellar Dysfunction in People with Multiple Sclerosis

“…11,12 Corporaal et al 12 also found a moderate correlation between total EDSS scores and trunk sway with EC (r = 0.542). However, unlike in the present study, they did not find a significant correlation with EO sway.…”

“…11,12 Further analysis revealed that EDSS cerebellar subscores correlate with postural sway in the EO and EC conditions. People with MS also showed a greater reliance on vision for control of sway in standing balance, a problem likely exacerbated by lower-limb proprioceptive loss.…”

“…10 People with EDSS scores of 3.0 to 6.0 are able to walk but have a variety of mild-to-moderate neurologic impairments, as indicated by functional system subscores. [11][12][13][14] Sensitive laboratory balance measures of postural sway may detect impairments that are not evident in standard neurologic assessments. 12,[15][16][17][18][19][20][21] In people with MS, increased postural sway, as measured using force plates or a trunk-mounted gyroscope, has been correlated with increased levels of disability, indicated by total EDSS scores.…”

“…12,[15][16][17][18][19][20][21] In people with MS, increased postural sway, as measured using force plates or a trunk-mounted gyroscope, has been correlated with increased levels of disability, indicated by total EDSS scores. 11,12 To date, no studies have investigated relationships between these sensitive balance measures and specific neurologic impairments identified by EDSS functional system subscores.…”

The Clinical Relevance of Force Platform Measures in Multiple Sclerosis: A Review

“…Moreover, computerised postural sway measures have been reported as correlated with disability and functional scales [24, 35, 65, 83]. Table 2 summarizes pros and cons pros of force platform measures, contrasted with those of clinical measures.…”