The Expanded Disability Status Scale runs from 0 to 10 in half steps, built from eight functional system scores and walking ability. Record each functional system and the ambulation findings, not only the final step, so the score can be reviewed.
Free sandbox · No credit card · 21 CFR Part 11 aligned
Functional systems
Pyramidal
FSPYRCerebellar
FSCERSensory
FSSENAmbulation
Maximum walking distance without aid
AMBDISTEDSS step
EDSSAt a glance
In trials
MS trials rarely analyse EDSS as a simple average. The key endpoint is time to confirmed disability progression: an increase that is sustained at a later visit, typically confirmed after 12 or 24 weeks. A common definition is an increase of at least 1.0 point from a baseline of 5.5 or less (1.5 points from a baseline of 0), or 0.5 points from a baseline above 5.5. Confirmation visits must not be affected by a relapse.
That definition has data consequences. Every EDSS needs a date, and the system needs to know whether the participant was in relapse, so relapses must be recorded on their own form with onset dates. Unscheduled visits for confirmation should use the same form as scheduled ones.
Progressive MS trials often combine EDSS with the timed 25-foot walk and the nine-hole peg test, counting progression on any of them. Record those tests as timed fields with units and trial numbers on the same visit.
| Assessment | Scr | BL | M3 | M6 | M9 | M12 | Unsch |
|---|---|---|---|---|---|---|---|
| EDSS with functional systems | |||||||
| Timed 25-foot walk | |||||||
| Relapse assessment | |||||||
| MRI |
Unscheduled visits for relapse or confirmation use the same forms
Structure
| Component | Range | What it covers |
|---|---|---|
| Pyramidal | 0 to 6 | Weakness and limb function |
| Cerebellar | 0 to 5 | Coordination and tremor |
| Brainstem | 0 to 5 | Eye movements, speech, swallowing |
| Sensory | 0 to 6 | Touch, pain and vibration sense |
| Bowel and bladder | 0 to 6 | Continence and urgency |
| Visual | 0 to 6 | Acuity and field |
| Cerebral | 0 to 5 | Mood and cognition |
| Ambulation | Distance and aid | Drives steps from about 4.0 to 7.5 |
Ranges shown follow the commonly used Kurtzke definitions. Use the scoring conventions and rater training specified by your protocol.
In Capture
The EDSS form holds each functional system score, walking distance and aid use, and the step itself, all as coded fields. A separate relapse form records onset and resolution, and the field-level audit trail shows who changed any score and why.
Anchor
Offset
Window
Epoch
TreatmentVisit location
Copy the template and add unscheduled visits in the free sandbox.
Rater quality
Many MS drugs have visible side effects or require monitoring that can reveal the treatment. To protect the EDSS from that bias, trials commonly use an examining neurologist who only performs the EDSS and does not see adverse event data, and a treating neurologist who manages the participant. In practice, that means planning each rater's access so safety and dosing data stay with the treating team.
Standardised scoring, such as the Neurostatus definitions widely used in trials, with rater certification, reduces the variability that makes small EDSS changes hard to interpret. Record the rater for each assessment so consistency can be checked.
Before go-live
Standardised definitions and certified raters.
No access to adverse events or dosing.
Functional systems, ambulation distance and aid.
Onset and resolution dates for confirmation rules.
Thresholds and confirmation interval in the analysis plan.
Same forms for confirmation and relapse visits.
The Expanded Disability Status Scale, a 0 to 10 scale of disability in multiple sclerosis based on a neurological examination and walking ability.
Commonly as an increase of 1.0 point from a baseline of 5.5 or less (1.5 from 0), or 0.5 from a baseline above 5.5, sustained at a confirmation visit 12 or 24 weeks later.
Needing intermittent or constant assistance on one side, such as a cane, to walk about 100 metres.
They determine the lower steps of the scale, and reviewers need them to check the step assigned.
Many trials use an examining rater who does not see safety or dosing data, to protect against unblinding.
The rater records the step with its components. Progression is derived from the recorded values in analysis.
Functional systems, ambulation and relapses together. Free sandbox.