Development and validation of a ten-item questionnaire with explanatory illustrations to assess upper extremity disorders: favorable effect of illustrations in the item reduction process.

BACKGROUND

The purpose of this study is to develop a short and valid measure for upper extremity disorders and to assess the effect of attached illustrations in item reduction of a self-administered disability questionnaire while retaining psychometric properties.

METHODS

A validated questionnaire used to assess upper extremity disorders, the Hand20, was reduced to ten items using two item-reduction techniques. The psychometric properties of the abbreviated form, the Hand10, were evaluated on an independent sample that was used for the shortening process.

RESULTS

Validity, reliability, and responsiveness of the Hand10 were retained in the item reduction process. It was possible that the use of explanatory illustrations attached to the Hand10 helped with its reproducibility. The illustrations for the Hand10 promoted text comprehension and motivation to answer the items. These changes resulted in high acceptability; more than 99.3% of patients, including 98.5% of elderly patients, could complete the Hand10 properly.

CONCLUSION

The illustrations had favorable effects on the item reduction process and made it possible to retain precision of the instrument. The Hand10 is a reliable and valid instrument for individual-level applications with the advantage of being compact and broadly applicable, even in elderly individuals.