Symptom Questionnaires

1 DePaul Symptom Questionnaire (DSQ)

The DePaul Symptom Questionnaire is a validated self-report instrument developed specifically for ME/CFS research and clinical assessment (Jason et al. 2006).

  • Purpose: Systematic assessment of ME/CFS symptom frequency and severity across multiple domains; enables classification according to multiple case definitions (Fukuda, CCC, ICC).
  • Administration: Self-administered paper or electronic questionnaire; approximately 20–30 minutes to complete.
  • Content: 54 symptom items, each rated on two scales: frequency (0 = none of the time, 4 = all of the time) and severity (0 = symptom absent, 4 = very severe). Additional items capture demographics, illness onset, and functional status.
  • Scoring: Composite domain scores are calculated for fatigue, post-exertional malaise, sleep dysfunction, pain, neurocognitive symptoms, autonomic dysfunction, neuroendocrine symptoms, and immune symptoms. A symptom is considered clinically significant when frequency \(\geq 2\) and severity \(\geq 2\).
  • Interpretation: The DSQ enables operationalized application of diagnostic criteria. For the ICC, PEM must score \(\geq 2\) on both frequency and severity, plus at least one symptom in each required category (neurological, immune, energy metabolism).
  • Strengths: Validated psychometric properties; enables systematic case identification; widely used in ME/CFS research, facilitating cross-study comparison.
  • Limitations: Self-report introduces subjective variability; cognitively impaired patients may require assistance; does not capture symptom timing or PEM delay characteristics.

2 Bell Disability Scale

The Bell Disability Scale provides a single-number rating of functional capacity (Roberts et al. 2016).

  • Purpose: Rapid assessment of overall functional impairment; tracking disease severity over time.

  • Administration: Clinician-rated or self-rated; takes less than 5 minutes.

  • Scoring: A single score from 0 to 100 in increments of 10:

    • 100: Normal activity, no symptoms
    • 80: Normal activity with effort, mild symptoms
    • 60: Can work part-time with rest periods; moderate symptoms
    • 50: Can perform light duties with rest; unable to work full-time
    • 40: Mostly homebound; severe symptoms with activity
    • 30: Mostly bedridden; severe symptoms at rest
    • 20: Bedridden most of the day; unable to perform self-care independently
    • 10: Bedridden and dependent; severe symptoms continuously
    • 0: Bedridden, unable to sit up; critically ill

  • Interpretation: Scores correspond approximately to NICE 2021 severity grades (National Institute for Health and Care Excellence 2021): Mild (\(\geq 60\)), Moderate (40–50), Severe (20–30), Very Severe (\(\leq 10\)).

  • Strengths: Quick to administer; provides a standardized severity metric; sensitive to change over time.

  • Limitations: Coarse granularity (10-point increments); does not capture symptom domains; subjective calibration varies between raters.

References

Jason, Leonard A, Kevin Corradi, Susan Gress, Stephanie Williams, and Susan Torres-Harding. 2006. β€œCauses of Death Among Patients with Chronic Fatigue Syndrome.” Health Care for Women International 27 (7): 615–26. https://doi.org/10.1080/07399330600803766.
National Institute for Health and Care Excellence. 2021. β€œMyalgic Encephalomyelitis (or Encephalopathy)/Chronic Fatigue Syndrome: Diagnosis and Management.” NICE guideline [NG206]. https://www.nice.org.uk/guidance/ng206.
Roberts, Eleanor, Simon Wessely, Trudie Chalder, Chin-Kuo Chang, and Matthew Hotopf. 2016. β€œMortality of People with Chronic Fatigue Syndrome: A Retrospective Cohort Study in England and Wales from the South London and Maudsley NHS Foundation Trust Biomedical Research Centre (SLAM BRC) Clinical Record Interactive Search (CRIS) Register.” The Lancet 387 (10028): 1638–43. https://doi.org/10.1016/S0140-6736(15)01223-4.