Paired comparison judgements of relative speech intelligibility

Abstract

The reliability, validity, and sensitivity of paired comparison judgements of speech intelligibility, organized into round robin and elimination tournaments, were studied. Normal hearing and hearing impaired subjects listened to paired samples of speech that were processed with two levels of background noise by 23 hearing aids in two replications. Monosyllabic word intelligibility scores were obtained under each condition in both replications. The results indicated that this paired comparison procedure was a valid, reliable and reasonably sensitive means of evaluating the relative intelligibility of hearing aid processed signals. For example, subjects chose the aid with the best, or second best average discrimination score in 94% of the elimination tournaments. Regarding reliability, the aid that was chosen first on the first trial was the first or second choice on the second trial more than 90% of the time at the O dB S/N ratio. The sensitivity of the procedure was such that at the O dB S/N ratio, the better aid was chosen in 75% of the matches when the difference between the “true” discrimination scores was in the 9%–12% range. [Work supported by NINCDS.]