Development and validation of a self-administered questionnaire for myasthenia gravis patients.

BACKGROUND

To date, the investigation of the epidemiological profile of myasthenia gravis (MG) is sparse, and the influence of environmental and lifestyle factors on the occurrence of the disease remains thus unknown. The main aim of this study, which is part of a European collaborative project (EuroMyasthenia), was to develop a self-administered questionnaire to investigate these potential predisposing factors for MG. No instrument for investigating these particular factors has previously been designed for MG patients.

MATERIAL AND

METHODS

The questionnaire was developed in 3 stages: (1) devising a draft questionnaire based on questions derived from previously validated questionnaires and self-designed questions on MG characteristics; (2) testing the questionnaire on Norwegian MG patients (n = 57), and (3) assessing the content and criterion validity, and test-retest reliability, of the final questionnaire.

RESULTS

The questionnaire was easy to use and showed good feasibility for MG patients. Psychometric evaluation established the validity and reliability of the self-designed questions on MG characteristics.

CONCLUSION

This is the first validated instrument developed to identify self-assessed environmental factors and potential predisposing factors for MG, and suitable for use in large-scale epidemiological studies.