Questionnaires and tools to assess ME/CFS symptoms or severity

Many different questionnaires, symptom scales and self-report tools can be used to measure the the severity or impact of particular ME/CFS symptoms, of ME/CFS, and the level of disability in ME/CFS patients.

Many questionnaires and symptom scales used for ME/CFS patients can also be used for patients with fibromyalgia or other chronic illnesses, for example those that assess pain, fatigue, overall disability or physical health, but some are designed to assess the unique combination of symptoms found in myalgic encephalomyelitis or chronic fatigue syndrome for example post-exertional malaise.

ME/CFS self-report tools

Commonly used self-report tools and questionnaires include:

• Bell CFIDS disability scale
• Chalder fatigue scale
• DePaul Pediatric Health Screening Questionnaire - for children and adolescents
• DePaul Post-Exertional Malaise Questionnaire
• DePaul Symptom Questionnaire
• The HFME Ability and Severity Scale (archived version)

Less commonly used

• AYME Functional Ability Scale - for children and adolescents
• Bansal Score Chart for ME/CFS
• Campbell CFS/Fibromyalgia Rating Scale
• CDC 2005 Symptom Inventory for CFS
• HFME 3 Part ME Ability and Severity Scale
• ME Association ME/CFS Disability Rating Scale
• Phoenix Rising Energy Index Scale
• Shepherd ME/CFS Disability Scale

General self-report tools

General self-report tools and questionnaires used in ME/CFS patients include:

• Borg CR-10
• Borg Rating of Perceived Exertion Scale (RPE scale)
• Energy Index Point Score
• Fatigue Severity Scale
• Fennell Phase Inventory
• Checklist Individual Strength
• Karnofsky Performance Scale
• Multidimensional Fatigue Inventory-20
• PROMIS F-SF
• Short Form 36-Item Health Survey
• Visual-analogue scale
• Widespread Pain Index
• International Symptom Scale (ICC)
• Functional Capacity Scale Definition
• Moss Ability Scale (original)
• Total Daily Symptom Score (TDSS)

Suitability of scales for severe ME

Some scales have a ceiling effect or floor effect, where a large range of variation in ME/CFS cannot be distinguished between, leading to a cluster or very high or very low scores.

Subjective and objective assessments

Symptom scales are usually subjective (based on the person's opinion) and so can be at risk of response bias. Symptom scales are a common form of Patient Rated Outcome Measure (PROM) used in clinical trials.

Symptom scales or other forms of self-assessment should be used together with objective measures, e.g., school/work attendance record, distance walked in 6 mins, cardiopulmonary exercise test (CPET), pain medication consumption, or VO2 max.

Notable studies

• 2000, Fatigue rating scales: an empirical comparison - (Abstract)
• 2011, Fatigue Scales and Chronic Fatigue Syndrome: Issues of Sensitivity and Specificity - (Full text)
• 2014, The delayed fatigue effect in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) - (Full text)

Significant differences were found between pre- and post-test measures in three MFI sub-scales of fatigue (general, mental, and physical) and on the depression scale of the HADS. However, there were no significant changes in motivation, activity level, or self-reported anxiety scores.

• 2016, Housebound versus nonhousebound patients with myalgic encephalomyelitis and chronic fatigue syndrome (Full text)
• 2016, The utility of patient-reported outcome measures among patients with myalgic encephalomyelitis/chronic fatigue syndrome - (Full Text)
• 2018, Operationalizing Substantial Reduction in Functioning Among Young Adults with Chronic Fatigue Syndrome - (Full text)

The four top performing subscales and their associated cutoffs were determined: Physical Functioning ≤ 80, General Health ≤ 47, Role Physical ≤ 25, and Social Functioning ≤ 50. Used in combination, these four cutoff scores were shown to reliably discriminate between the patients and controls in our sample of young adults

• 2020, Validation of the Severity of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome by Other Measures than History: Activity Bracelet, Cardiopulmonary Exercise Testing and a Validated Activity Questionnaire: SF-36 - (Full text)

Symptoms limiting the test were exhaustion in all patients, muscle pain in 80% as one of the symptoms at the end of the test, and dizziness in 8%.

See also

• Symptom scales (category)
• Mild ME/CFS
• Moderate ME/CFS
• Severe ME/CFS
• Very severe ME/CFS
• Patient Rated Outcome Measure

See myalgic encephalomyelitis.

See chronic fatigue syndrome.

International Consensus Criteria (ICC) - A set of diagnostic criteria, based on the Canadian Consensus Criteria, that argued for the abandonment of the term "chronic fatigue syndrome" and encouraged the sole use of the term "myalgic encephalomyelitis".

See International Consensus Criteria.

subjective outcome An outcome of a clinical trial that depends on the judgement or opinion of the assessor or patient, e.g. asking if fatigue has increased or decreased "a little" or "a lot", patient questionnaires like the Chalder Fatigue Scale, and other patient-reported outcome measures (PROMs).

two-day cardiopulmonary exercise test (CPET) - A diagnostic test which involves testing an ME/CFS patient exercising on an exercise machine, while monitoring their respiration, especially oxygen consumption. This test is repeated the following day in order to confirm the patient's inability to replicate the first-day performance. This test is thought to be the most objective way to detect post-exertional malaise.

See two-day cardiopulmonary exercise test.

VO2 Max (VO2max) - the maximum amount of oxygen the body can utilize during a specified period of usually intense exercise (Volume of O2 Maximal)

subjective outcome An outcome of a clinical trial that depends on the judgement or opinion of the assessor or patient, e.g. asking if fatigue has increased or decreased "a little" or "a lot", patient questionnaires like the Chalder Fatigue Scale, and other patient-reported outcome measures (PROMs).

myalgic encephalomyelitis (M.E.) - A disease often marked by neurological symptoms, but fatigue is sometimes a symptom as well. Some diagnostic criteria distinguish it from chronic fatigue syndrome, while other diagnostic criteria consider it to be a synonym for chronic fatigue syndrome. A defining characteristic of ME is post-exertional malaise (PEM), or post-exertional neuroimmune exhaustion (PENE), which is a notable exacerbation of symptoms brought on by small exertions. PEM can last for days or weeks. Symptoms can include cognitive impairments, muscle pain (myalgia), trouble remaining upright (orthostatic intolerance), sleep abnormalities, and gastro-intestinal impairments, among others. An estimated 25% of those suffering from ME are housebound or bedbound. The World Health Organization (WHO) classifies ME as a neurological disease.

Short Form 36-Item Health Survey (SF-36) - A 36-item patient-reported questionnaire, used to determine patient health status and quality of life.

See Short Form 36-Item Health Survey.

chronic illness any long-term illness, regardless of the severity. Chronic illnesses are typically incurable, requiring long-term management.