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Expanded Disability Status Scale


The Kurtzke Expanded Disability Status Scale (EDSS) is a method of quantifying disability in multiple sclerosis. The EDSS replaced the previous Disability Status Scales which used to bunch people with MS in the lower brackets.

The EDSS quantifies disability in eight Functional Systems (FS) and allows neurologists to assign a Functional System Score (FSS) in each of these. The Functional Systems are:

EDSS steps 1.0 to 4.5 refer to people with MS who are fully ambulatory. EDSS steps 5.0 to 9.5 are defined by the impairment to ambulation.
Kurtzke Expanded Disability Status Scale
0.0 Normal neurological examination
1.0 No disability, minimal signs in one FS
1.5 No disability, minimal signs in more than one FS
2.0 Minimal disability in one FS
2.5 Mild disability in one FS or minimal disability in two FS
3.0 Moderate disability in one FS, or mild disability in three or four FS. Fully ambulatory
3.5 Fully ambulatory but with moderate disability in one FS and more than minimal disability in several others
4.0 Fully ambulatory without aid, self-sufficient, up and about some 12 hours a day despite relatively severe disability; able to walk without aid or rest some 500 meters
4.5 Fully ambulatory without aid, up and about much of the day, able to work a full day, may otherwise have some limitation of full activity or require minimal assistance; characterized by relatively severe disability; able to walk without aid or rest some 300 meters.
5.0 Ambulatory without aid or rest for about 200 meters; disability severe enough to impair full daily activities (work a full day without special provisions)
5.5 Ambulatory without aid or rest for about 100 meters; disability severe enough to preclude full daily activities
6.0 Intermittent or unilateral constant assistance (cane, crutch, brace) required to walk about 100 meters with or without resting
6.5 Constant bilateral assistance (canes, crutches, braces) required to walk about 20 meters without resting
7.0 Unable to walk beyond approximately five meters even with aid, essentially restricted to wheelchair; wheels self in standard wheelchair and transfers alone; up and about in wheelchair some 12 hours a day
7.5 Unable to take more than a few steps; restricted to wheelchair; may need aid in transfer; wheels self but cannot carry on in standard wheelchair a full day; May require motorized wheelchair
8.0 Essentially restricted to bed or chair or perambulated in wheelchair, but may be out of bed itself much of the day; retains many self-care functions; generally has effective use of arms
8.5 Essentially restricted to bed much of day; has some effective use of arms retains some self care functions
9.0 Confined to bed; can still communicate and eat.
9.5 Totally helpless bed patient; unable to communicate effectively or eat/swallow
10.0 Death due to MS

Below is a graph showing the average time a person spends in each EDSS level.

Despite being the standard method of evaluating disability, the EDSS is criticised for placing too much emphasis on use of the legs and being insensitive to clinical change. Quantifying MRI scans is widely used in clinical trials to evaluate disease status but correlates rather poorly with disability probably because so many MS lesions are silent (have no clinically detectable symptoms). Many other measures have been used to quantify various aspects of disability in MS including:

Of these, only the Scripps Neurologic Rating Scale and the Fatigue Severity Scale (FSS) are widely recognised, but their use is dwarfed by that of the EDSS and MRI evaluation.

Expanded Disability Status Scale links:
The psychometric properties of clinical rating scales used in multiple sclerosis
Clinical scoring methods for multiple sclerosis
Validation of the functional assessment of multiple sclerosis quality of life instrument
A comparison of two neurologic scoring instruments for multiple sclerosis
Clinical appropriateness: a key factor in outcome measure selection
Multiple sclerosis: assessment of disability and disability scales

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