The Expanded Disability Status Scale measures your current level of disability. Neurologists use it to benchmark and monitor changes in multiple sclerosis. Since MS is a progressive condition, your EDSS is likely to increase over time though most people will not experience the scale’s highest levels of disability.
Expanded Disability Status Scale (EDSS)
What is the EDSS?
Developed by neurologist John Kurtzke to replace his Disability Status Scale (DSS), it is a way of measuring disability and progression in multiple sclerosis. The EDSS is also used widely in clinical trials.
Scores are based on examination by a neurologist, and climb by half unit increments from 0 to 10 as your level of disability increases.
EDSS 1.0 to 4.5
These scores apply to those who can walk unaided. They are based on the level of neurological impairment of eight functional systems in your brain. These functional systems are networks of neurons that are responsible for the specific tasks listed below:
- pyramidal - muscle weakness or difficulty moving limbs
- cerebellar - ataxia, loss of balance, coordination or tremor
- brainstem - problems with speech, swallowing and nystagmus
- sensory - numbness or loss of sensations
- bowel and bladder function
- visual function - problems with sight
- cerebral functions - problems with thinking and memory
- other
EDSS 5.0 to 9.5
These are defined by walking impairment, which is why the EDSS is sometimes criticised for its reliance on just one aspect for its main measure of disability.
Although the scale takes into account disability associated with advanced MS, most people will never reach these scores. If you feel worried about how your MS might progress, a Canadian study may offer some perspective. It took place when the Disability Status Score was still used, before it was replaced by the EDSS in 1983. This large study of people with MS at a clinic in Ontario, found that 51% of people had a Disability Status Score score of five or lower. 88% had a score of seven or lower. Treatment of MS has greatly advanced in the decades since.
Expanded Disability Status Scale (EDSS)
| Score | Description |
|---|---|
| 0 | Normal neurological examination, no disability in any functional system |
| 1.0 | No disability, minimal signs in one functional system |
| 1.5 | No disability, minimal signs in more than one functional system |
| 2.0 | Minimal disability in one functional system |
| 2.5 | Mild disability in one functional system or minimal disability in two functional systems |
| 3.0 | Moderate disability in one functional system, or mild disability in three or four functional systems. No walking impairment |
| 3.5 | Moderate disability in one functional system and more than minimal disability in several others. No walking impairment |
| 4.0 | Significant disability but self-sufficient and up and about some 12 hours a day. Able to walk without aid or rest for 500m |
| 4.5 | Significant disability but 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. Able to walk without aid or rest for 300m |
| 5.0 | Disability severe enough to impair full daily activities and ability to work a full day without special provisions. Able to walk without aid or rest for 200m |
| 5.5 | Disability severe enough to prevent full daily activities. Able to walk without aid or rest for 100m |
| 6.0 | Requires a walking aid – cane, crutch, etc. – to walk about 100m with or without resting |
| 6.5 | Requires two walking aids – pair of canes, crutches, etc. – to walk about 20m without resting |
| 7.0 | Unable to walk beyond approximately 5m even with aid. Essentially restricted to a wheelchair; though wheels a standard wheelchair and able to get in and out alone. Up and about in wheelchair some 12 hours a day |
| 7.5 | Unable to take more than a few steps. Restricted to a wheelchair and may need help getting in and out. Can wheel but cannot carry on in a standard wheelchair for a full day and may require a motorised wheelchair |
| 8.0 | Essentially restricted to a bed or chair or being pushed in wheelchair. May be out of bed much of the day. Retain many self-care functions. Generally has effective use of arms |
| 8.5 | Essentially restricted to a bed for much of the day. Has some effective use of arms, retains some self-care functions |
| 9.0 | Confined to bed. Can still communicate and eat |
| 9.5 | Confined to bed and totally dependent. Unable to communicate effectively or eat/swallow |
| 10.0 | Death due to MS |
Limitations of the EDSS
The EDSS is the most widely used measure for disability progression in MS. However, this scale has some limitations. EDSS scores can vary due to the complex scoring rules and the subjective nature of the neurological examination. This means that there is a risk that different health professionals might score you differently.
Some critics argue that the changes between steps on the scale are unequal for example 1.0 to 2.0 and 4.0 to 5.0. From level 4.0 upwards the scale focuses on walking ability and underestimates the importance of upper body function. Arm and hand function is vital in self-care and independence. Some functional areas are not assessed in the EDSS, such as mood, energy levels and quality of life. This means that the EDSS is not always a good measure of the impact MS has on you.
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Rating neurologic impairment in multiple sclerosis: an expanded disability status scale (EDSS).
Neurology 1983;33(11):1444-1452.
Summary (link is external)
The natural history of multiple sclerosis: a geographically based study. 1 Clinical course and disability.
Brain 1989;112:133-146.
Summary (link is external)
Outcome measures in clinical trials for multiple sclerosis.
CNS Drugs 2017;31(3):217-236.
Full article (link is external)
