What's a Kurtzke? by Rick Korejwo,Ph.D. There seems to be a rash of questions about Kurtzke numbers and I have to admit that I can't just say "read such-and-such." What is a Kurtke number and what does it mean? This would have been a lot easier to explain prior to 1983 but it's too late for that now. Let me begin with Dr. John F. Kurtzke. Back in 1955 Dr. Kurtzke set out to establish a quantified scale which rated the disabilities of MS patients. The scale, known as the Disability Status Scale (DSS) was relatively straight forward and, in simplified terms was as follows: Kurtzke rating general observed status 0 a normal neurological exam 1 No disability, minimal abnormal signs 2 Minimal disability in only one of the functional systems: strength, coordination, sensation,bladder, vision, mental 3 Independently walking but moderate disability in one of the functional systems. 4 Walking independently for up to 12 hours/day, but sever disability in one functional system 5 Walking without aid for 200 meters but with disability sever enough to prevent working a full day. 6 A cane, crutch or brace is required to walk 100 meters 7 Walking limited to 5 meters with an aid; the patient is mostly confined to a wheelchair 8 Confined to bed or chair; maintained effective use of arms. 9 Helpless bed bound patient 10 Death from MS OK, that seems pretty clear so far and it would be if things hadn't changed. They did. The old Kurtzke scale had some shortcomings. It was a little mobility dependant and was not sufficiently precise if it was to be used by everyone at any location to describe MS patients. A universal rating system is required for a number of reasons. It allows an ability for the total description of a patients status in a shorthand which would be reasonably understood by any number of people separated in time and place. It would also provide a criteria upon which, buy objective clinical evaluation, a patients progress or regression might be measured. Objectivity in evaluation is important because subjective comments like "better" and "fine" which might be given by a patient are more likely to be distorted by such non-MS factors as, whether they got three green lights in a row on the way to the office or by simple denial of disability. To refine the process of ratings, a clearer consideration of all of the areas which MS effects had to have a place in the rating system. It was reasonably clear that other areas of disability had to receive higher priority in evaluation. To this end there was a restatement of the Kurtzke scale by Kurtzke in 1957. Most noteworthy in the changes was the emergence of functional groups, later to be called functional systems(FS). These were identified as Pyramidal (motor function)(P), Cerebellar (Cll), Brain Stem (BS), Sensory (S), Bowel & Bladder (BB), Visual (V), Cerebral or Mental (Cb), and, the always necessary, Other(O). Rather than these individual areas running from 1-10 as the full scale these FS generally ran on scales of 0 to 5 or 6. The "Other" FS was simply given a "problems=yes" or "problems=no" rating. If you are interested in understanding how these various FS scale values are derived I have included a supplement which was provided as an appendix to the 1983 EDSS paper by Kurtzke. Since there were 8 FS areas of up to 6 degrees of variability and our original 10 degree criteria of ambulation we ended up with a scale with well over 20000 possible values. To say that rater variability could create different impressions would be a gross understatement. Clearly some structure had to be imposed that would allow two people communicating about a level of disability to have some common scale of measurement. What emerged from this was a revised scale with a fair number of ambiguities and informed subjective decisions. To an extent it has remained unchanged since it was revised in 1983. It is a widely accepted measure of clinical evaluation of MS based on clinically observed, not patient described, problems associated with MS. The revised measurement tool is most commonly referred to as the Expanded Disability Status Scale (EDSS) What follows is a generalized overview of the EDSS. EDSS step 0 This is roughly the same as the old DSS step 0 which described an uneventful clinical neurological examination. All the FS areas except the Cll FS were unremarkable. The exception for the Cll was to allow mood aberrations such as Euphoria or depression. EDSS step 1.0 This includes one FS grade of 1 excluding Cll but no FS grades above 0. EDSS step 1.5 This includes two or more FS grades of 1, again except the Cll FS but no FS grade above 1 EDSS step 2.0 One FS grade of 2 but all other FS equal or less than 1. EDSS step 2.5 This includes 2 FS grades of 2 or less and all other FS grades equal or less than 1. EDSS grades of 3.0 but less than 4.0 are generally areas where normal day to day activities can be followed but with mild disorders present and observed. Persons in steps 3 and 4 are generally able to be active for the normal course of a day can engage in normal activities provided that they are not attempting activities which require special physical skills. EDSS step 3.0 One FS grade of 3, OR three or four FS grades of 2. Other FS grades are 1 or 0. EDSS step 3.5 One FS grade of 3 PLUS one or two grade 2, two FS grade 3,or five FS grade 2, other FS grades are 1 or 0. EDSS grades between 4.0 but less than 5.0 are areas where ambulation/work/daily activities start to take precedence over the precise FS grades. EDSS step 4.0 Combinations of two FS grades just exceeding 3. or one grade 3 plus grade 2; or one FS grade 4 alone. With FS grades exceeding 3.5 there must be full ambulation (including the ability to walk without aid for 500 meters. There must also be the ability to carry out full daily activities to include work of average physical difficulty. EDSS step 4.5 The same minimum grade requirement as step 4.0 plus the ability to walk without aid or rest for approximately 300 meters and to work a full day in a position of average physical difficulty. EDSS steps five and 6 involve a greater latitude of subjective evaluation by the doctor. In general this area involve a broader range of possible problems in the various FS. In these steps the patient may not be house bound but is seldom able to perform a full day of work. The primary discriminator in the four steps from 5.0 to 6.9 rest with walking. To demonstrate the subjective nature of the area, these criteria are further weighed by "usual best function" rather than by supramaximal effort or insufficient performance. EDSS step 5 requires ambulation of about 200 meters without aid or rest. Disability is sufficient to impair full daily activities. Usual FS criteria is one FS 5 or a combination of grades which exceed step 4.0. EDSS step 5.5 requires ambulation of about 100 meters without aid or rest. Other criteria are inability to work part time without special provisions. Two or more FS grades of 5 are ample criteria also. EDSS step 6 requires assistance to walk about 100 meters. This may include rest or the assistance of aids. More than two FS grades of 3 plus are an alternate criteria. EDSS step 6.5 requires assistance to walk about 20 meters without resting but aids (canes, crutches, braces, or people)FS equivalents are as they were in 6.o with two or more FS of 3+. EDSS steps 7-9 are for the severely involved who are typically restricted to bed or wheelchairs. Although the FS scores are still computed, they become less relevant and the scale starts to take on an appearance similar to the original DSS. EDSS step 7.0 The patient is essentially restricted to a wheelchair with the ability to walk limited to about 5 meters with aid. Usual FS equivalents are multiple FS grades greater than 4 or a pyramidal grade of 5. EDSS step 7.5 describes a patient essentially restricted to a wheelchair with the ability to take only a few steps. A transfer capability is still present. In general they are capable of movement in a wheelchair by themselves but are incapable of continuing a course of daily activities. EDSS step 8.0 describes a patient in a bed or, passively, in a wheelchair. In general they maintain many selfcare abilities and, typically, maintain the use of their arms. EDSS step 8.5 describes patients who are primarily restricted to bed with only limited periods when they are able to use a wheelchair. They may still have effective use of one or both arms and can provide some selfcare functions. EDSS step 9.0 are helpless *bedbound patients who can communicate and eat with assistance. FS grades are usually multiple groups of 4+. EDSS step 9.5 describes the totally helpless bed bound patient who is incapable of communicating, eat or swallow. Again, FS scores are multiples of 4+. EDSS step 10 is equated as death due to MS. Although relatively rare, it includes death caused by *brainstem involvement or death as a consequence of chronic bedridden state typical of terminal pneumonia, uremia, or cadiorespiratory failure. Now you have a full range knowledge of what the EDSS or "Kurtzke" numbers are and what they mean. It is simply a rating system developed, over time, to describe the general state of a patient. If over the course of a test period 90% of the patients have an decrease in their Kurtzke score of one step, this is a good thing. Conversely, if they have an increase in their "Kurtzke" score of 1 or more steps you have an idea that you didn't accomplish much. Let me just emphasize that these are all to be based on the objective results of a neurological exam and not on the reported conditions by the patient. While the patient can assist the neurologist in identifying the areas of potential problem, it is the neurologist who must objectively document the state of the patients condition. More recent studies (circa 1992) have indicated inter and intra ratings scores have shown remarkable similarities indicating that the scale, although not perfect, has provided a fairly accurate means of defining neurological conditions. ---------------- FS scores Pyramidal Functions 0. Normal 1. Abnormal signs without disability 2. Minimal disability 3. Mild or moderate paraparesis or hemiparesis; sever monoparesis 4. Marked paraparesis or hemiparesis; moderate quadriparesis; or monoplegia. 5. Quadraplegia V. Unknown Cerebellar Functions 0. Normal 1. Abnormal signs without disability 2. Mild ataxia 3. Moderate truncal or limb ataxia 4. Severe ataxia, all limbs 5. Unable to perform coordinated movements due to ataxia. V. Unknown X. is used throughout after each number when weakness (grade 3 or more on pyramidal) interferes with testing. Brain Stem Functions 0. Normal 1. Signs only 2. Moderate nystagmus, or other mild disability 3. Severe nystagmus, marked extraocular weakness, or moderate disability of other cranial nerves. 4. Marked dysarthria or other marked disability 5. Inability to swallow or speak. V. Unknown Sensory Functions 0. Normal 1. Vibration or figure-writing decrease only, in one or two limbs. 2. Mild decrease in touch or pain or position sense, and/or moderate decrease in vibration in one or two limbs; or vibratory (c/s figure writing) decrease alone in three or four limbs. 3. Moderate decrease in touch or pain or position sense, and/or essentially lost vibration in one or two limbs; or mild decrease in all proprioceptive tests in three or four limbs. 4. Marked decrease in touch or pain or loss of proprioception, alone or combined, in one or two limbs; or moderate decrease in touch or pain and/or severe proprioceptive decrease in more than two limbs. 5. Loss (essentially) of sensation in one or two limbs; or moderate decrease in touch or pain and/or loss of proprioception for most of the body below the head. 6. Sensation essentially lost below the head. V. Unknown Bowel & Bladder Functions 0. Normal 1. Mild urinary hesitancy, urgency, or retention. 2. Moderate hesitancy, urgency, retention of bowels or bladder, or rare urinary incontinence. 3. Frequent urinary incontinence. 4. In need of almost constant Catherization. 5. Loss of bladder function. V. Unknown Visual Functions 0. Normal 1. Scotoma with visual acuity (corrected) of 20/30 to 20/59. 3. Worse eye with large scotoma, or moderate decrease in fields, but with maximal visual acuity (corrected) of 20/60 to 20/99. 4. Worse eye with marked decrease in fields and maximal visual acuity (corrected) of 20/100 to20/200; grade 3 plus maximal acuity of better eye of 20/60 or less. 5. Worse eye with maximal visual acuity (corrected) less than 20/200; grade 4 plus maximal acuity of better eye of 20/60 or less. 6. Grade 5 plus maximal visual acuity of better eye of 20/60 or less. V. Unknown X. is added to grade 0 to 6 for presence of temporal pallor. Cerebral Functions 0. Normal. 1. Mood alteration only (Does not affect DSS score) 2. Mild decrease in mentation. 3. Moderate decrease in mentation. 4. Marked decrease in mentation (chronic brain syndrome - moderate) 5. Dementia or chronic brain syndrome - sever or incompetent. V. Unknown Other Functions. 0. None. 1. Any neurologic findings attributed to MS (specify). V. Unknown. Richard J. Korejwo, PhD. 1992 ---------------------- You may copy and distribute verbatim copies of the text files above in any medium, provided that you publish the copyright notice and discaimer if that text file contains one, also you may not charge any fee for doing so without permission of the author or authors of any text file. 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