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Conrad Notes
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R. B. Lipton, MD, Albert Einstein School of Medicine, Bronx, NY, and W.F. Stewart, PhD, Johns Hopkins University, Baltimore, Md, devised a self-administered questionnaire for assessing migraine patients. Headache frequency and severity along with disability contribute to the 100-point score. This tool was valid compared with diary information. It was also proved reliable according to test-retest data. Lipton and Stewart expect the ImQ to help physician-patient communication and decision-making, to reliably assess migraine headaches, and to serve as an outcome measure.

Questionnaire for migraine sufferers The ImQ uses an overall rating scale of 1-100 for compiling scores about:

  • frequency and average duration of headache experienced during the last three months

  • pain intensity

  • missed days and percent reduced effectiveness related to work, household chores, and social/recreational activities

  • need for bedrest

  • presence of nausea, photophobia, and phonophobia

Study sample for testing ImQ Interviewers telephoned randomly over 5,000 households and convinced 77 percent of them to participate. This pool led to identification of 800 migraine patients. Ninety-seven patients enrolled in the validation experiment and 117 completed the test-retest exercise.
Assessing the validity of ImQ Each of the 97 selected migraineurs agreed to keep a daily diary for 90 days. The requested information included rating his/her effectiveness at paid and household work, medication use, stress level, psychological status, and whether a headache occurred on that day. In addition, a two-page questionnaire asked for more details on the headache such as pain intensity, symptoms, missed days at work and social activities, and an estimate of reduced effectiveness due to the headache. Each patient also completed the ImQ at the end of the 90-day period.
Assessing the reliability of ImQ This group of 117 migraine patients completed the ImQ twice about 40 days apart. The ImQ included the same items listed above but required recall covering the previous three months. Each overall ImQ score equalled the sum of average pain intensity, headache frequency, total lost days and lost day equivalents due to reduced effectiveness in each activity (see above) related to the headache.
Results of validity and reliability tests The ImQ and diary results were similar on:

  • number of days of headache

  • percentage of headaches with severe pain

  • percentage of time lying down due to headache

  • missed social days due to headache

The ImQ score was higher than obtained by diary on:

  • pain intensity

  • lying down one or more hours

  • percentage of days with headache leading to missed work or chores

  • percentage of days with reduced effectiveness because of headache at work, with chores, and social or nonwork activities
Correlation tests Lipton and Stewart found "The correlation between ImQ items and equivalent measures from the diary ranged from 0.31 to 0.75, with a median of 0.52...[and] ... between the ImQ score and the equivalent diary severity scores [the correlation] was relatively high (p=0.69)."

The test-retest correlations of individual items in the ImQ ranged from 0.64 to 0.86. Cronbach's alpha for internal consistency reliability was 0.85 and Pearson's correlation coefficient for test-retest reliability was 0.86 for the ImQ.

Comments on proposed questionnaire The present version of the ImQ needs simplification. Lipton and Stewart found the ImQ difficult to self-score by most patients. As an outcome measure, the ImQ satisfied the tests for validity and reliability. Experience by others generally follows to determine the application of the ImQ in clinical practice and research.
For professional correspondence, please contact Dr. Lipton at: Fax (203) 321-1044.

Eugene A. Conrad

Presented at Thirty-ninth Annual Scientific Meeting, American Association for the Study of Headache (AASH), June 19-22, 1977
Copyright © 1997 Conrad Group, Inc. All Rights Reserved
Eugene A. Conrad, PhD, MPH / ISSN 1078-2230 / September 1977

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