Comparison of the traditional paper visual analogue scale questionnaire with an Apple Newton electronic appetite rating system (EARS) in free living subjects feeding ad libitum

Objective: Assessing the value of a newly developed electronic visual analogue scale questionnaire (Apple Newton Message Pad) with the traditional paper method for appetite rating. Design: In a random, crossover design, subjects completed both electronic and paper questionnaires to compare results obtained by the two methods; individual methods were completed consecutively to assess test-retest reliability; preference was established using a questionnaire. Setting/Subjects: Healthy, free-living adults were studied for comparison of methods (n=12), test-retest reliability (n = 8) and preference (n = 13). Intervention: Visual analogue scales were completed each waking hour to assess appetite. Preference was assessed after both methods were completed. Results: There was no significant difference in the hourly results obtained by the paper and electronic methods for 'desire to eat', 'how much can you eat now', 'urge to eat' and 'preoccupation with thoughts of food'. Small differences in 'hunger' and 'fullness' ratings were noted (similar to 5% mean difference between methods, P < 0.05), but patterns of change and sensitivity for these and all other parameters remained similar for both methods across the visual analogue scale. Test-retest reliability demonstrated was similar for both methods. Seven (54%) subjects preferred to use the paper questionnaire, five (38%) the electronic method and one (8%) had no preference. Conclusions: The electronic Apple Newton questionnaire is as sensitive and reliable as the paper method, has the advantage that it automatically records the time of data acquisition and data collection and processing are more efficient for the researcher. The two methods should not be used interchangeably.