January 28, 2026

Commonly Used Rating Scales in RLS Research

Research related to RLS often relies on questionnaires and rating scales to provide objective clinical data. These tools provide a baseline to help researchers and clinicians assess clinical diagnoses and evaluate symptom severity, treatment effectiveness and patients' physical and emotional well-being. Understanding these scales can make it easier to interpret published research findings and clinical results.

International RLS Study Group Score (IRLS)

The International Restless Legs Study Group (IRLSSG) developed and validated a 10-item rating scale to indicate how symptoms have affected a patient over the course of one week. This test is administered by a physician, but answers are self-reported by the patient. Each of the 10 questions asks the respondent to rate their experiences with RLS on a scale from 0 (no symptoms) to 4 (severe and frequent symptoms), producing a total score between 0 and 40. Generally, scores in the range of 1–10 correspond to mild RLS, 11–20 to moderate, 21–30 to severe, and 31–40 to very severe RLS.

How is it used? The IRLS is a commonly administered questionnaire used in research and clinical practice to rate the severity of RLS symptoms and can be used to help determine the best course of treatment for RLS patients.

RLS-6 Scale

The RLS-6 scale measures the impact of RLS on daily life. This 6-item questionnaire evaluates questions on a scale from 0 to 10, with higher numbers indicating more severe RLS. The questions ask for individuals to rate satisfaction with sleep and severity of symptoms while falling asleep, during the night, during the day while sitting or lying, and during the day when moving around.

How is it used? The RLS-6 is an instrument to assess RLS severity within specific and pragmatic parameters. It can be used to supplement the IRLS.

Cambridge-Hopkins Diagnostic Questionnaire (CH-RLSq)

This questionnaire is a validated diagnostic tool used by physicians to assess and identify RLS. The questions address basic diagnostic features of RLS such as frequency and timing of symptoms, relief of symptoms with movement, and impact on daily life or sleep patterns.

How is it used? The CH-RLSq is commonly used in research to validate RLS diagnoses and differentiate RLS from conditions with similar characteristics.

Suggested Immobilization Test (SIT)

The SIT is a validated tool that assesses leg discomfort and leg movements during a 60-minute period. The test is administered in the evening in a clinical setting. Participants recline at a 45-degree angle with legs outstretched and are instructed to avoid voluntary movement for the duration of the test. The test records surface electromyograms from the anterior tibialis muscles to detect leg movements. A high number of leg movements during the test may help differentiate patients with RLS from those without RLS.

How is it used? The SIT provides a standardized testing condition to measure the severity of RLS symptoms by quantifying leg movements and subjective discomfort. This test is often used to determine whether potential treatments might be helpful to treat RLS symptoms.

Pittsburgh Sleep Quality Index (PSQI)

This validated questionnaire is administered by a physician and evaluates overall sleep quality over a one-month period. The questions fall into seven categories: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. Five additional questions rated by the respondent’s roommate or bed partner are included for clinical purposes but are not scored. Each question is scored from 0 to 3, with higher scores indicating greater sleep disturbances.

How is it used? The PSQI may be helpful during RLS research studies to determine the effectiveness of medications, interventions and other therapies for improving sleep.

The World Health Organization-5 Well-Being Index (WHO-5)

This questionnaire evaluates five statements to measure mental well-being over two weeks. Statements are rated on a 6-point scale, with higher scores indicating better mental health.

How is it used? The WHO-5 may be used in RLS research to study the relationship of RLS and mental health or to examine mental health outcomes based on treatment response.