The Kurtzke Expanded Disability Status Scale (EDSS) is a method of quantifying disability in multiple sclerosis

Multiple sclerosis

Multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...

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The EDSS quantifies disability in eight Functional Systems (FS) and allows neurologists to assign a Functional System Score (FSS) in each of these.

Functional systems

Kurtzke defines functional systems as follows:

• pyramidal
  Pyramidal cell
  Pyramidal neurons are a type of neuron found in areas of the brain including cerebral cortex, the hippocampus, and in the amygdala. Pyramidal neurons are the primary excitation units of the mammalian prefrontal cortex and the corticospinal tract. Pyramidal neurons were first discovered and...
  
  
• cerebellar
  Cerebellum
  The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...
  
  
• brainstem
• sensory
  Sensory system
  A sensory system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory receptors, neural pathways, and parts of the brain involved in sensory perception. Commonly recognized sensory systems are those for vision, hearing, somatic...
  
  
• bowel and bladder
  Urinary bladder
  The urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...
  
  
• visual
• cerebral
• other

Results and clinical meaning

EDSS steps 1.0 to 4.5 refer to people with MS who are fully ambulatory. EDSS steps 5.0 to 9.5 are defined by the impairment to ambulation.

The clinical meaning of each possible result is the following:

• 0.0: Normal Neurological Exam
• 1.0: No disability, minimal signs on 1 FS
• 1.5: No disability, minimal signs on 2 of 7 FS
• 2.0: Minimal disability in 1 of 7 FS
• 2.5: Minimal disability in 2 FS
• 3.0: Moderate disability in 1 FS; or mild disability in 3 - 4 FS, though fully ambulatory
• 3.5: Fully ambulatory but with 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
• 4.0: Fully ambulatory without aid, up and about 12hrs a day despite relatively severe disability. Able to walk without aid 500 meters
• 4.5: Fully ambulatory without aid, up and about much of day, able to work a full day, may otherwise have some limitations of full activity or require minimal assistance. Relatively severe disability. Able to walk without aid 300 meters
• 5.0: Ambulatory without aid for about 200 meters. Disability impairs full daily activities
• 5.5: Ambulatory for 100 meters, disability precludes full daily activities
• 6.0: Intermittent or unilateral constant assistance (cane, crutch or brace) required to walk 100 meters with or without resting
• 6.5: Constant bilateral support (cane, crutch or braces) required to walk 20 meters without resting
• 7.0: Unable to walk beyond 5 meters even with aid, essentially restricted to wheelchair, wheels self, transfers alone; active in wheelchair about 12 hours a day
• 7.5: Unable to take more than a few steps, restricted to wheelchair, may need aid to transfer; wheels self, but may require motorized chair for full day's activities
• 8.0: Essentially restricted to bed, chair, or wheelchair, but may be out of bed much of day; retains self care functions, generally effective use of arms
• 8.5: Essentially restricted to bed much of day, some effective use of arms, retains some self care functions
• 9.0: Helpless bed patient, can communicate and eat
• 9.5: Unable to communicate effectively or eat/swallow
• 10.0: Death due to MS