Validity and reliability of the Migraine-Specific Quality of Life Questionnaire (MSQ version 2.1)

Objective.-To assess the scaling properties, reliability, and validity of t he revised Migraine-Specific Quality of Life Questionnaire (MSQ) (Version 2 .1) ((C) 1992, 1996, 1998 Glaxo Wellcome Inc.). Background.-The MSQ is a disease-specific, quality-of-life instrument with three hypothesized scales that has been developed, tested, and revised. Methods.-The study used a multicenter, nondrug, prospective, parallel group , quasi-experimental design. Patients with migraine were recruited at outpa tient headache specialty practices and were administered the MSQ, the Medic al Outcomes Study 36-Item Short Form Health Survey (SF-36), and migraine sy mptom questionnaires at baseline, 4 weeks, and 12 weeks. Internal consisten cy (Cronbach alpha) and 4-week test-retest reproducibility (intraclass corr elation coefficients) were estimated to assess reliability. Construct valid ity was assessed using an adaptation of the Campbell and Fiske multitrait-m ultimethod approach and by correlating MSQ scores with symptom measures. Results.-A total of 267 subjects enrolled in the trial. The criteria for su mmated rating scales were all met. The internal consistency coefficients ra nged from 0.86 to 0.96, and the intraclass correlation coefficients ranged from 0.57 to 0.63 across the three dimensions. As anticipated, the MSQ dime nsions had low-to-modest correlations with the two component scores of the SF-36 and were modestly to moderately correlated with migraine symptoms. Conclusions.-The MSQ is a reliable instrument in the assessment of quality of life for patients with migraine with items that can be summed without we ights. The MSQ has demonstrated evidence of construct validity.