Integration of Cognitive Impairment in the Expanded Disability Status Scale of 215 Patients with Multiple Sclerosis

Abstract

Background: Estimates of the prevalence of cognitive impairment among patients with multiple sclerosis (MS) range between 40 and 70%. The current cerebral functional system (CFS) of the Expanded Disability Status Scale (EDSS) is subjective. Aim: To define a new cerebral functional system (NCFS) based on neuropsychological evaluation (NE). Methods: We prospectively included 215 MS patients. NE evaluated cognitive functions. Fatigue was assessed with the Fatigue Impact Scale. The NCFS was devised with grades from 0 to 5, excluding depression but including fatigue. Grade 1 of the NCFS was integrated in the EDSS as other functional scores. The NCFS and new EDSS including the NCFS were compared with the current CFS and EDSS. Results: 215 patients (69% women, 67% with relapsing-remitting MS, median EDSS 3.0) were assessed. 98% of these patients presented fatigue and/or cognitive impairment with the NCFS compared to 62% with the CFS. The NCFS was higher than the CFS, and the EDSS had changed in 31% of the 113 patients with an EDSS <3.5. Change in functional score was not correlated to current age or age at onset of MS. Conclusions: We propose a new CFS grading based on NE, including fatigue, and integrating grade 1 at EDSS.

The EDSS integration with the Brief International Cognitive Assessment for Multiple Sclerosis and orientation tests

“…In an attempt to better estimate the CFS, Brissart et al 26 used several neuropsychological tests, embracing five cognitive functions, and a fatigue rating scale. The CFS calculation they proposed was standardized, although the exact number of tests patients went through was variable, as many tests exploring each function were optional.…”

Progressive Multiple Sclerosis

“…14 A worsening of 0.5 or 1 points sustained over 3-6 months is a common definition of disease progression. The EDSS has several drawbacks including its construct as an ordinal scale, 15 high inter-rater variability, 46 over-reliance on lower extremity function, 16 lack of meaningful cognitive component, 17 and relative insensitivity to longitudinal change in specific ranges of the scale. 18 These features have limited the utility of the EDSS both in clinical practice as well as in clinical trials.…”

Clinical trials in progressive multiple sclerosis: lessons learned and future perspectives

“…61–64 The EDSS relies heavily on lower extremity function with cognition and upper extremity function having smaller impacts. 65,66 Using the EDSS to measure progression of disability has inherent problems. Several methods of calculating disability progression using EDSS have been utilized and time to worsening in EDSS (normally 0.5 or 1 point sustained for 3 or 6 months) is most commonly used.…”