ToolsCalculators
Expanded Disability Status Scale (EDSS) / Functional Systems Score
Stages MS-related disability from Functional Systems scores and ambulation.
Expanded Disability Status Scale (EDSS) / Functional Systems Score
Pyramidal functional system grade
0-6
Cerebellar functional system grade
0-5
Brainstem functional system grade
0-5
Sensory functional system grade
0-6
Bowel & bladder functional system grade
0-6
Visual (optic) functional system grade
0-6
Cerebral (mental) functional system grade
0-5
Ambulation status
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When to use
- Staging disability and tracking progression in multiple sclerosis, including trial eligibility and outcome reporting.
Formula
Below EDSS 4.0, the score is derived from the pattern of Kurtzke Functional System (FS) grades (pyramidal, cerebellar, brainstem, sensory, bowel/bladder, visual, cerebral). From EDSS 4.0 upward, ambulation distance/assistance becomes the dominant determinant.
Pearls and pitfalls
- This is a computable reconstruction of Kurtzke's original algorithm; formal EDSS scoring requires a full neurological Functional Systems exam by a trained rater.
- EDSS is heavily weighted toward ambulation and can be insensitive to cognitive or upper-limb decline.