The Brief Fatigue Inventory: Comparison of Data Collection Using a Novel Audio Device with Conventional Paper Questionnaire

An Electronic Portable Information Collection audio device (EPIC-Vox) has been developed to deliver questionnaires in spoken word format via headphones. Patients respond by pressing buttons on the device. The aims of this study were to determine limits of agreement between, and test-retest reliability of audio (A) and paper (P) versions of the Brief Fatigue Inventory (BFI). Two hundred sixty outpatients (204 male, mean age 55.7 years) attending a sleep disorders clinic were allocated to four groups using block randomization. All completed the BFI twice, separated by a one-minute distracter task. Half the patients completed paper and audio versions, then an evaluation questionnaire. The remainder completed either paper or audio versions to compare test-retest reliability. BFI global scores were analyzed using Bland-Altman methodology. Agreement between categorical fatigue severity scores was determined using Cohen's kappa. The mean (SD) difference between paper and audio scores was −0.04 (0.48). The limits of agreement (mean difference ± 2SD) were −0.93 to +1.00. Test-retest reliability of the paper BFI showed a mean (SD) difference of 0.17 (0.32) between first and second presentations (limits −0.46 to +0.81). For audio, the mean (SD) difference was 0.17 (0.48) (limits −0.79 to +1.14). For agreement between categorical scores, Cohen's kappa = 0.73 for P and A, 0.67 (P at test and retest) and 0.87 (A at test and retest). Evaluation preferences (n = 128): 36.7% audio; 18.0% paper; and 45.3% no preference. A total of 99.2% found EPIC-Vox “easy to use.” These data demonstrate that the English audio version of the BFI provides an acceptable alternative to the paper questionnaire.