The structure of an instrument for assessing the effects of assistive devices and altered working methods in women with rheumatoid arthritis.

OBJECTIVE

To use Rasch analysis to transform the ordinal score from a newly developed instrument, the Evaluation of Daily Activities Questionnaire (EDAQ), in order to obtain unidimensional linear measures; to analyze whether items change in difficulty with interventions; and to follow changes in subjects' degree of ability.

METHODS

Twenty-one women with rheumatoid arthritis rated their perceived difficulty without and with assistive devices or altered working methods using the EDAQ; the EDAQ consists of 102 items of daily activities, divided into 11 dimensions.

RESULTS

All items in the EDAQ could be structured into an acceptable model from "hard" to "easy" with the subjects overall measures ranging from "more able" to "less able." Forty-one items showed a significant reduction of difficulty with interventions. For some items results indicated that easier initial difficulty led to greater effect of interventions. In general, difficulty without assistive devices could not predict difficulty with interventions. Twenty women demonstrated a significant increase in activities of daily living (ADL) ability after interventions.

CONCLUSION

The EDAQ analyzed with the Rasch model, demonstrated a hierarchical order of difficulty in 102 items showing that it was possible to evaluate the effect of using assistive devices or altered working methods.