Chalder fatigue scale

The Chalder fatigue scale (sometimes known as the Chalder scale) is a symptom scale created by Trudie Chalder used to measure the severity of tiredness in fatiguing illnesses. It has been used by Esther Crawley in the PACE trial and in her paediatric research.

Questions
1. Do you have problems with tiredness?

2. Do you need to rest more?

3. Do you feel sleepy or drowsy?

4. Do you have problems starting things?

5. Do you lack energy?

6. Do you have less strength in your muscles?

7. Do you feel weak?

8. Do you have difficulties concentrating?

9. Do you make slips of the tongue when speaking?

10. Do you find it more difficult to find the right word?

11. How is your memory?

Risks and flaws
The Chalder fatigue scale has been criticized as not being a reliable scale for clinical or research settings for ME/CFS. Criticisms include:
 * may not be sensitive enough for patients with severe and very severe ME
 * having a low ceiling in determining fatigue thus resulting in "a marked degree of overlap between the scores from the moderately and severely ill,"
 * questions are too general and will capture those with other fatiguing illnesses, e.g., question 4 correlates with self-rated measures of depression,
 * two alternative scoring methods are used, the bimodal (0-11) and Likert (0-33) score, which can generate contradictory findings, which happened in PACE trial

Notable studies

 * 1993, Development of a fatigue scale
 * 2011, PACE trial
 * 2017, Public Review - Draft of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) Common Data Elements (CDE); Fatigue Subgroup Materials (Full Text)

Learn more

 * Chalder fatigue scale
 * ME analysis - The Chalder fatigue scale
 * 2016, Fatigued by scales as outcome measures
 * 2018, Analysis of the Chalder fatigue scale submitted by a team of Science for ME forum members to the NIH/CDC Common Data Elements review.