ARTICLE #13: Kurtzke Expanded Disability Status Scale (EDSS)
Author(s): By Marsha L Tarver, PhD,
Associate Director of Education,
MS Center of Excellence, West,
VA Puget Sound Health Care System
The Kurtzke Disability Status Scale ( DSS ) was developed by Dr. John Kurtzke in the 1950s to measure the disability status of people with multiple sclerosis. The purpose was to create an objective approach to quantify the level of functioning that could be widely used by health care providers diagnosing MS. The scale was modified several times to more accurately reflect the levels of disabilities clinically observed. The scale was renamed the Kurtzke Expanded Disability Status Scale (EDSS).
The EDSS provides a total score on a scale that ranges from 0 to 10.
- The first levels 1.0 to 4.5 refer to people with a high degree of ambulatory ability
- The subsequent levels 5.0 to 9.5 refer to the loss of ambulatory ability.
The range of main categories include:
- (0) -- normal neurologic exam, to (4.5) -- ambulatory without aid or rest for 200 meters;
- (5) disability severe enough to impair full daily activities, to (10) -- death due to MS .
In addition, it also provides eight subscale measurements called Functional System (FS) scores. These subscale categories are listed below. The levels of function within each category refer to the eight functional systems affected by MS.
Functional Systems
The eight Functional Systems (FS) and their abbreviations are as follows:
1. Pyramidal (motor function) (P)
2. Cerebellar (C11)
3. Brainstem (BS)
4. Sensory (S)
5. Bowel and Bladder (BB)
6. Visual (V)
7. Cerebral or Mental (Cb)
8. Other (O)
Functional System Score
The Functional Systems (FS) are scored on a scale of 0 (low level of problems) to 5 (high level of problems) to best reflect the level of disability observed clinically. The “Other” category is not rated numerically, but measures disability related to a particular issue, like motor loss.
In contrast, the total EDSS score is determined by two factors: gait and FS scores. EDSS scores below 4.0 are determined by the FS scores alone. People with EDSS scores of 4.0 and above have some degree of gait impairment. Scores between 4.0 and 9.5 are determined by both gait abilities and the FS scores. For simplicity, many experts gauge the EDSS scores between 4.0 and 9.5 entirely by gait, without considering the FS scores.
The EDSS is widely used and accepted as a valid tool to clinically measure and evaluate MS patients' level of functioning. Below is the EDSS:
Kurtzke Expanded Disability Status Scale
0 |
Normal neurological exam (all grade 0 in Functional Systems (FS); cerebral grade 1 acceptable). |
1 |
No disability, minimal signs in one FS (i.e., one grade 1 excluding cerebral grade 1). |
1.5 |
No disability, minimal signs in more than one FS (more than one grade 1 excluding cerebral grade 1). |
2.0 |
Minimal disability in one FS (one FS grade 2, others 0 or 1). |
2.5 |
Minimal disability in two FS (two FS grade 2, others 0 or 1). |
3.0 |
Moderate disability in one FS (one FS grade 3, others 0 or 1), or mild disability in three or four FS (three-four FS grade 2, others 0 or 1). |
3.5 |
Fully ambulatory but with moderate disability in one FS (one grade 3 and one or two FS grade 2) or two FS grade 3, others 0 or 1, or five FS grade 2, others 0 or 1. |
4.0 |
Fully ambulatory without aid, self-sufficient, up and about some 12 hours a day despite relatively severe disability consisting of one FS grade 4 (others 0 or 1), or combinations of lesser grades exceeding limits of previous steps. Able to walk without aid or rest some 500 meters. (0.3 miles) |
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, usually consisting of one FS grade 4 (others 0 or 1) or combinations of lesser grades exceeding limits of previous steps. Able to walk without aid or rest for some 300 meters. (975 ft) |
5.0 |
Ambulatory without aid or rest for about 200 meters (650 feet); disability severe enough to impair full daily activities (e.g., to work full day without special provisions). (Usual FS equivalents are one grade 5 alone, others 0 or 1; or combinations of lesser grades usually exceeding specifications for step 4.0) |
5.5 |
Ambulatory without aid or rest for about 100 meters (325 ft); disability severe enough to impair full daily activities. (Usual FS equivalents are one grade 5 alone, others 0 or 1; or combinations of lesser grades usually exceeding specifications for step 4.0) |
6.0 |
Intermittent or constant unilateral assistance (cane, crutch, brace) required to walk about 100 meters (325 ft) with or without resting. (Usual FS equivalents are combinations with more than two FS grade 3+) |
6.5 |
Constant bilateral assistance (canes, crutches, braces) required to walk about 20 meters (65 ft). (Usual FS equivalents are combinations with more than two FS grade 3+) |
7.0 |
Unable to walk beyond about 5 meters (16 ft) even with aid, essentially restricted to wheelchair; wheels self in standard wheelchair a full day and transfers alone; up and about in wheelchair some 12 hours a day. Usual FS equivalents are combinations with more than one FS grade 4+; very rarely pyramidal grade 5 alone. |
7.5 |
Unable to take more than a few steps; restricted to wheelchair; may need aid in transfers, wheels self but cannot carry on in standard wheelchair a full day; may require motorized wheelchair; usual FS equivalents are combinations with more than one FS grade 4+ |
8.0 |
Essentially restricted to bed or chair or perambulated in wheelchair; but may be out of bed much of the day; retains many self-care functions; generally has effective use of arms. Usual FS equivalents are combinations, generally grade 4+ in several systems. |
8.5 |
Essentially restricted to bed for much of the day; has some effective use of arm(s); retains some self-care functions. Usual FS equivalents are combinations, generally grade 4+ in several systems. |
9.0 |
Helpless bed patient; can communicate and eat. Usual FS equivalents are combinations, mostly grade 4. |
9.5 |
Totally helpless bed patient; unable to communicate effectively or eat/swallow. Usual FS equivalents are combinations, almost all grade 4+ |
10 |
Death due to MS. |
Date Posted: May 8, 2006