Eric C. Hoover1, Katherine N. Palandrani1
Department of Hearing and Speech Sciences, University of Maryland, College Park, MD, USA

In pure-tone audiometry, threshold is defined as the lowest stimulus level to meet the stopping criteria and not, as in most other psychophysical procedures, as the stimulus level corresponding to a specific probability of detection. A mathematical relationship between audiometric thresholds and the probability of detection remains elusive. This limits our ability to control the audibility of signals amplified by hearing aids and prevents equivalent thresholds from being obtained using other psychophysical methods. Our hypothesis was that the relationship could be established through an analysis of the probability of meeting the stopping criteria at a given stimulus level. A combinatorial solution was obtained for standard audiometric stopping criteria. Results showed that the probability of detection at threshold is maximized at different stimulus levels depending on the events that occur during the test. This suggests that it is possible to relate audiometric thresholds to the probability of detection, but that there are multiple solutions reflecting the multiple possible ways to satisfy the stopping criteria.

Acknowledgements: Work supported by NIH/NIDCD R01 DC015051 to Frederick Gallun.