The Expanded Disability Status Scale (EDSS) is a way of measuring disability in multiple sclerosis (MS) and monitoring changes in the level of a person’s disability over time.

The scale ranges from 0 to 10 in 0.5-unit increments, representing higher levels of disability.

It categorizes disability levels primarily on the basis of walking ability, although it also considers other neurological functions.

This article examines the EDSS for multiple sclerosis, what the scores mean, the limitations of the test, and more.

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The EDSS is the scale with the most widespread use in the clinical study of MS.

A neurologist, John Kurtzke, developed the scale in the 1980s. It assesses changes in the severity of MS symptoms over time.

Scores range from 0, which represents a normal neurological exam, to 10, which represents death due to MS. The scale rises in increments of 0.5.

For example, a score from 1.0 to 4.5 indicates that a person is able to walk, while a score of 5.0 and above signifies impairment to walking and the need for walking assistance.

Focus areas

The EDSS’s main focus is mobility and the ability to walk. A significant portion of the scale focuses on walking ability, or “ambulation,” with higher scores representing greater impairment to walking.

However, it also evaluates various other functions, such as motor, sensory, bowel and bladder, visual, and cognitive functioning.


Healthcare professionals use the EDSS in clinical trials to assess the effectiveness of treatments and interventions for MS.

It also helps them monitor the progression of the disease and make informed decisions about treatment strategies.

The EDSS evaluation begins with the assessment of eight functional systems that MS may affect:

  • Pyramidal: Muscle strength or motor function.
  • Cerebellar: Coordination and balance.
  • Brainstem: Functions such as swallowing, speech, and eye movements.
  • Sensory: Touch, pain, and temperature sensation.
  • Bowel and bladder: Control of bowel and bladder functions.
  • Visual: Visual acuity and field of vision.
  • Cognitive: Memory, reasoning, and attention.
  • Other: Any other neurological findings attributed to MS.

Medical professionals score each functional system on a scale ranging from 0 (normal function) to varying maximum scores (indicating severe dysfunction) depending on the system.

The higher the points a person has on the scale, the more serious their condition.

For example:

  • Walking (ambulation) ability: A significant part of the EDSS score relates to the person’s ability to walk, with the scale mentioning specific distances for reference. For example, an EDSS score of 4.0 indicates that a person can walk without aid or rest for at least 500 meters, while a score of 6.0 indicates they need assistance (such as a cane or crutch) to walk about 100 meters.
  • Substantial limitations (5.0-8.0): People who score in this range can maintain some self-care, with increasing scores indicating a higher level of disability and the need for more support or assistance.
  • Nonambulatory scores (8.5 to 9.5): At these levels, people are restricted to bed or a chair and require assistance with most activities of daily living.

Despite its wide use, the EDSS does have limitations. These include:

  • Too focused on ambulation: Critics argue that the EDSS may not capture the full spectrum of MS symptoms, especially cognitive impairments and fatigue, as it heavily focuses on physical mobility.
  • Subjectivity: The scale is somewhat subjective, particularly in the middle range of scores, and can vary slightly depending on the examiner. This may lead to inconsistencies in measuring disease progression or response to treatment.
  • Poor sensitivity to change: The EDSS is not highly sensitive to small but clinically significant changes in a patient’s condition, especially in the early and later stages of the disease. This lack of sensitivity makes it hard to detect minor improvements or deteriorations, which can be crucial for assessing whether treatments are working.
  • Scale discontinuity: Ability in MS is not always linear, and the EDSS does not account for relapses and remissions. This discontinuity can make it difficult to interpret changes in scores.

Despite these limitations, the EDSS remains a cornerstone in MS research and clinical management, providing a common language for describing disability levels.

However, an ongoing effort exists to develop and validate additional tools and measures that can complement the EDSS and provide a more comprehensive view of a patient’s condition and response to treatment.

Here are the answers to some commonly asked questions about EDSS.

What is a good EDSS score?

A ‘good’ EDSS score is generally in the lower range, from 0 to 3.0, indicating normal neurological examination or minimal disability.

Lower scores reflect fewer impairments in daily activities and ambulation.

What is the life expectancy of someone with a high EDSS score?

Life expectancy can vary significantly among people with MS.

While higher EDSS scores (indicating greater disability) have an association with a reduced life expectancy compared to the general population, advancements in treatment and care have improved outcomes over time.

Specific life expectancy predictions on the basis of EDSS scores are challenging due to health variations and the impact of ongoing treatment advancements.

What is a 10 EDSS score?

An EDSS score of 10 signifies death due to MS. This score marks the endpoint of the scale.

The EDSS is a cornerstone in the management and study of multiple sclerosis, providing a standardized framework for evaluating disease progression and treatment outcomes.

Although there are some limitations, the scoring system is a good way to measure a person’s ability and disease severity with MS.