The influence of visual feedback on closed-set word test performance over time.

Closed-set word tests can be implemented with or without trial-by-trial visual feedback. Feedback is considered to increase subject motivation yet its influence on performance is unknown. The aim of this study was to compare performance on the Four Alternative Auditory Feature (FAAF) test with and without visual feedback over a 24-week period following fitting of a hearing aid. A total of 32 elderly subjects were recruited as new users and fitted monaurally with the same model of linear, programmable hearing aid that provided in excess of 20 dB insertion gain at 2-4 kHz. Half of the subjects were provided with visual feedback. In these subjects, mean performance increased by 5% across the study period. The improvement in performance over time was statistically significant on analysis of variance (p < 0.05). Mean performance did not increase in the remaining subjects who were not provided with feedback. If closed-set word tests are to be used with visual feedback to measure changes over time, the potentially confounding effects of practice must be controlled carefully. Alternatively, omitting feedback leads to simpler experimental designs.