Background: The modified Rankin Scale (mRS) is a 6-level outcome scale used to assess level of function in neurological disease.
Objective: We examined the interobserver reliability and intraobserver reliability of the mRS-9Q, a 9-question "yes/no" survey that measures the mRS score in neurosurgical and neurological patients.
Methods: The mRS-9Q was administered in person or by telephone, and a Web-based tool was used to calculate the mRS score and to perform error checking. Part 1 compared the mRS-9Q with an mRS structured interview (n = 80). Part 2 compared mRS-9Q administration by telephone and by hard copy (n = 80). Part 3 compared mRS-9Q administration by an expert interviewer with administration by a nonexpert (n = 83). Part 4 examined reproducibility of the mRS-9Q over a 2-week period (n = 84).
Results: Agreement was very good in all study parts. In Part 1 (mRS-9Q vs mRS with structured interview), κ = 0.80 and κw = 0.96. In Part 2 (mRS-9Q telephone vs hard copy), κ = 0.83 and κw = 0.95. In Part 3 (mRS-9Q expert vs nonexpert), κ = 0.73 and κw = 0.93. In Part 4 (mRS-9Q reproducibility), κ = 0.76 and κw = 0.93.
Conclusion: The mRS-9Q is a simple, easy-to-administer survey with a custom Web-based mRS calculation and error-checking tool. The mRS-9Q can reliably determine the mRS by hard copy survey or by telephone and can be administered by experts or nonmedical study personnel. The mRS-9Q can be used to measure functional outcome in a broad population of patients with neurosurgical and neurological diseases.