Neurology
General medicine
The Fatigue Severity Scale (FSS) is a nine-item self-report questionnaire that primarily assesses the impact of fatigue on functioning, rather than just the sensation of being tired. It was developed particularly for multiple sclerosis and lupus, and has since been used in many other clinical situations.
Number of questions
9 items
Approximate duration
2 to 4 minutes
Population
Adults, particularly those with multiple sclerosis or lupus
Modality
self-administered questionnaire
Terms of contract
Self-administered questionnaire completed by the patient, indicating their level of agreement with each of the nine statements based on the past week. Distinguish fatigue from sleepiness, which is assessed using other tools. The mean score is only calculated if the completeness rules for the chosen version are met; use the version authorised by the copyright holder.
Score interpretationFSS
Average of the nine responses rated from 1 to 7; result from 1 to 7.
Total score
First reading
A threshold of around 4 is frequently used to indicate significant fatigue, without constituting a universal diagnosis. Convention adopted for this sheet: average from 1 to 7; average ≥ 4 as a frequently used benchmark. Do not confuse this convention with the 9–63 sum in a patient history.
Fatigue is common across many diseases and contexts. The FSS cannot identify its cause.
Frequently asked questions
Does the FSS measure sleepiness?
Should you use the sum or the average?
What are its limitations?
Sources and references
Dr. Lauren Krupp
Krupp LB et al., Arch Neurol, 1989
In practice
Full name
Fatigue Severity Scale
Method
self-administered questionnaire
Language
French
Authors
Dr. Lauren Krupp
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