Comparison of the 40-item Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-40) with a short-form five-item version (ALSAQ-5) in a longitudinal survey

Abstract

Objectives: To compare results on the 40-item Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-40) with those gained on the short-form five-item Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-5) in a longitudinal study.

Design: Postal survey. Copies of the ALSAQ-40 which incorporates the five items of the ALSAQ-5, were completed on two occasions. Respondents were also asked to indicate how much change they had experienced since baseline on each of the five domains of the questionnaire.

Setting: The database of all patient members of the Motor Neurone Disease Association for England, Wales and Northern Ireland.

Subjects: Nine hundred and twenty-seven patient members returned questionnaires at baseline, and 764 completed questionnaires at both baseline and follow-up.

Results: Results on the five dimensions of the ALSAQ-40 and ALSAQ-5 were found to be highly correlated, and 95% confidence intervals on mean scores were found to overlap for each dimension. The instruments both provide a similar picture of change in terms of their responsiveness. For example, effect sizes were calculated for patients who claimed their health had deteriorated a little since baseline, and gave almost identical results (e.g. for the Physical functioning domain effect sizes of 0.12 and 0.11 were found on the long and short measures respectively).

Conclusions: Results suggests that the ALSAQ-5 provides similar results to the ALSAQ-40 yet with considerable economy. In instances where a very brief health status measure is required then the ALSAQ-5 may be the instrument of choice.