From the FDA Drug Label
The EDSS is a scale that quantifies disability in patients with MS and ranges from 0 (normal neurologic exam) to 10 (death due to MS). At entry, study participants were without exacerbation during the prior 2 months and had Kurtzke Expanded Disability Status Scale (EDSS) scores ranging from 1.0 to 3.5.
The lowest EDSS score a fully ambulatory but not unrestricted patient can receive is 1.0, as this score indicates no disability, but a score of 0 indicates a normal neurologic exam. A fully ambulatory patient would likely have some degree of disability, so a score of 1.0 is the most appropriate. 1
From the Research
The lowest EDSS score a patient who is fully ambulatory but not unrestricted can receive is 4.0. This score indicates that the patient can walk without aid or rest for about 500 meters but has moderate disability in one functional system or mild disability in several functional systems that impairs full daily activities. The EDSS is a method of quantifying disability in multiple sclerosis, ranging from 0 (normal neurological exam) to 10 (death due to MS) 2. The scale focuses heavily on walking ability, particularly in the middle range (EDSS 4.0-7.0). At EDSS 4.0, patients experience limitations in their walking but can still walk without assistance for significant distances. The restriction in ambulation, even if the patient is otherwise functioning well, prevents scoring below 4.0 on this scale. As the disease progresses, higher scores would be assigned based on decreasing ambulatory capacity, with EDSS 4.5 indicating ability to walk without aid for about 300 meters, and EDSS 5.0 indicating ability to walk without aid for about 200 meters.
Some key points to consider when evaluating EDSS scores include:
- The patient's ability to walk without aid or rest for a certain distance
- The presence of moderate disability in one functional system or mild disability in several functional systems
- The impact of these disabilities on the patient's daily activities
- The progression of the disease and the resulting increase in EDSS score over time
It's worth noting that the EDSS score is just one measure of a patient's disability and should be considered in conjunction with other clinical assessments and patient-reported outcomes. However, in terms of the EDSS score itself, 4.0 is the lowest score that a fully ambulatory but not unrestricted patient can receive. This is based on the definition of the EDSS scale and the criteria for assigning scores within the 4.0-7.0 range 2.
In clinical practice, the EDSS score is an important tool for monitoring disease progression and evaluating the effectiveness of treatments. By understanding the criteria for assigning EDSS scores, clinicians can better interpret the results and make informed decisions about patient care. For example, a patient with an EDSS score of 4.0 may require more frequent monitoring and follow-up appointments to assess their disease progression and adjust their treatment plan as needed.
Overall, the EDSS score of 4.0 is a critical threshold for patients who are fully ambulatory but not unrestricted, and clinicians should be aware of the criteria for assigning this score and the implications for patient care.