Most MS studies use the Kurtzke Expanded Disability Status Scale to assess whether people are getting better or worse. Determined through neurological testing and examination, EDSS ratings range from 0 to 10. They are based in part on a person’s ability to walk, but assessments of these eight functional systems (FS) are even more important:
- Pyramidal (motor functions like walking)
- Cerebellar (coordination)
- Brain stem (speech and swallowing)
- Sensory (touch, vibration and pain)
- Bowel and bladder functions
- Other (includes any other neurological findings due to MS)
Defining the EDSS Ratings
Note: From 0.0 to 4.0, people can walk without assistance, and the EDSS is based on functional system scores.
|0.0:||Normal neurological exam.|
|1.0:||No disability, but minimal signs in one functional system (FS).|
|1.5:||No disability, but minimal signs in more than 1 FS.|
|2.0:||Minimal disability in 1 FS.|
|2.5:||Mild disability in 1 FS, or minimal disability in 2 FS.|
|3.0:||Moderate disability in 1 FS or mild disability in 3 or 4 FS. However, the person is still fully ambulatory.|
The person is fully ambulatory, but has moderate disability in 1 FS and mild disability in 1 or 2 FS; or moderate disability in 2 FS; or mild disability in 5 FS.
Note: From 4.0 to 7.5, the EDSS score is based mainly on how far the person can walk and with what kind of assistance.
|4.0:||The person is fully ambulatory without aid and is up and about most of the day (12 hours) despite relatively severe disability. He or she can walk 500 meters without aid or rest.|
|4.5:||The person is fully ambulatory without aid and is up and about much of day. He or she can work a full day but may otherwise have some limitations to full activity or require minimal assistance. This is considered relatively severe disability. The person can walk 300 meters without assistance.|
|5.0:||The person can walk 200 meters without aid or rest. Disability impairs full daily activities, such as working a full day without special provisions.|
|5.5:||The person is able to walk 100 meters without aid or rest. Disability precludes full daily activities.|
Note: Point 6, which represents walking with a cane, is often used as an endpoint in studies looking at progression of disability.
|6.0:||The person needs intermittent or unilateral constant assistance (cane, crutch or brace) to walk 100 meters with or without resting.|
|6.5:||The person needs constant bilateral support (cane, crutch or braces) to walk 20 meters without resting.|
|7.0:||The person is unable to walk beyond 5 yards even with aid, and is essentially restricted to a wheelchair. However, he or she wheels self and transfers alone, and is active in a wheelchair about 12 hours a day.|
Note: From 7.5 to 10.0, the main determinant of EDSS is one’s ability to move from a wheelchair to a bed, and to self-care.
|7.5:||The person is unable to take more than a few steps, is restricted to a wheelchair, and may need help in transferring. He or she wheels self, but may require a motorized chair for a full day’s activities.|
|8.0:||The person is essentially restricted to bed, a chair or a wheelchair, but may be out of bed much of day. The person can still care for him or herself and has generally effective use of arms.|
|8.5:||The person is essentially restricted to bed much of day, but has some effective use of arms and retains some self-care functions.|
|9.0:||The person is confined to bed but can still communicate and eat.|
|9.5:||The person is totally helpless and bedridden and is unable to communicate, eat and swallow.|
|10.0:||Death due to MS.|
Shortcomings of the EDSS
While the EDSS is widely used in most MS studies, it is not common in day-to-day medicine, for a few reasons:
- It is insensitive to changes in people’s conditions, particularly once they have difficulty walking
- It over-emphasizes the ability to walk
- It is insensitive to cognitive dysfunction in MS
- Calculating EDSS scores is complicated, with complex rules for rating the findings of neurological exams and for translating these into scores on functional system status
- It is not sensitive to many clinical changes that a person with MS experiences