What are the items of the Cambridge‑Hopkins Restless Legs Syndrome questionnaire (CH‑RLSq)?

Cambridge-Hopkins Questionnaire for Restless Legs Syndrome (CH-RLSq)

The Cambridge-Hopkins diagnostic questionnaire (CH-RLSq) is a 13-item self-completed screening tool that evaluates the 4 core diagnostic criteria of RLS while systematically excluding common mimics such as positional discomfort and leg cramps. 1

Core Structure and Purpose

The CH-RLSq was specifically designed to enable large-scale RLS diagnosis without requiring a trained interviewer, making it particularly valuable for epidemiological studies and population-based screening. 1

The 13 Questions Address:

• The 4 essential diagnostic criteria for RLS: 1

  • Urge to move the legs, usually accompanied by uncomfortable sensations
  • Symptoms that begin or worsen during rest or inactivity
  • Symptoms partially or totally relieved by movement
  • Symptoms worse in the evening or at night than during the day

• Differential diagnosis items to exclude RLS mimics: 1

  • Positional discomfort (symptoms that resolve simply by changing position without continued movement)
  • Leg cramps (sudden, painful muscle contractions)

Validation and Performance Characteristics

The CH-RLSq demonstrates strong psychometric properties when validated against expert clinical diagnosis: 2

• Sensitivity: 87.2% for detecting true RLS cases 2
• Specificity: 94.4% for correctly identifying non-RLS individuals 2
• Positive predictive value: 85.5% in population-based samples 2

The questionnaire has been validated across multiple populations, including an Arabic translation showing 71% sensitivity and 100% specificity in Lebanese populations. 3

Clinical Recommendation Status

The American Academy of Sleep Medicine classifies the CH-RLSq as a "Recommended" diagnostic tool because it meets all three Movement Disorder Society criteria: 1

1. Utilized in appropriate RLS patient populations
2. Applied by multiple independent research teams beyond the original developers
3. Demonstrates excellent clinimetric properties in validation studies

Practical Advantages

• Self-administered format eliminates the need for trained interviewers, reducing cost and time burden 1
• Systematic mimic exclusion built into the questionnaire structure improves diagnostic accuracy compared to simple symptom checklists 1
• Validated for population surveys where individual clinical interviews would be impractical 2

Important Caveats

While the CH-RLSq provides excellent screening capability, it remains a questionnaire-based tool rather than a definitive clinical diagnosis. 1 Positive screens should prompt clinical evaluation, particularly to assess iron status (ferritin ≤100 ng/mL or transferrin saturation <20%), identify exacerbating medications, and evaluate for associated conditions like end-stage kidney disease, pregnancy, or peripheral neuropathy. 4

The questionnaire's strength lies in its balance between comprehensive diagnostic coverage and practical feasibility for large-scale use, making it superior to single-question screeners while avoiding the 45-minute administration time required by telephone diagnostic interviews. 1