Developing an assistive technology usability questionnaire for people with neurological diseases.

PURPOSE: This study describes the development of a questionnaire for assessing the usability of assistive technologies accessible to people with neurological diseases. METHODS: A Delphi study was conducted to identify relevant items for the questionnaire. After that, the content validity was addressed to identify the essential items. Once the questionnaire was designed following the results of the Delphi study and content validity, the reliability, validity, and the Rasch model of the questionnaire were examined. RESULTS: Two rounds of the Delphi study were carried out. A total of 73 participants (42 experts and 31 users) participated in round 1, and 59 people (27 experts and 32 users) in round 2. A total of 53 and 29 items were identified in rounds 1 and 2, respectively. In the content validity, we found nine items above the threshold of 0.58. Finally, ten items were included in the questionnaire. Fifty-one participants participate in the reliability and validity of the questionnaire. The internal consistency reliability of the questionnaire analyzed by Cronbach's Alpha was α = 0,895. There was moderate to considerable concordance among our questionnaire items test-retest in the Kappa coefficient and a strong association between test-retest in the Spearman's coefficient ρ = 0.818 (p<0,001). The intraclass correlation coefficient was 0,869 with a 95% confidence interval (0,781;0,923). There was a strong correlation between the total scores of the new questionnaire and other validated questionnaires analyzed with Spearman's coefficient ρ = 0.756 (p<0,001). The ten items demonstrated a satisfactory fit to the Rasch model. CONCLUSIONS: The present study suggested that the new questionnaire is a reliable 10-item usability questionnaire that allows subjective and quick assessment of the usability of assistive technologies by people with neurological diseases.