A simple single-interval adaptive procedure for estimating thresholds in normal and impaired listeners.

This report presents a single-interval adaptive procedure for measuring thresholds in untrained normal and impaired listeners. The accuracy of the procedure is evaluated using Monte Carlo methods and human data allowing a method to be proposed for deciding in advance the number of trials required to achieve a specified level of accuracy. The number of trials depends on the slope of the psychometric function. The slope of the psychometric function is evaluated in normal and impaired listeners, and is found to give a useful guide to the required number of trials. The single-interval up/down procedure is subsequently compared with two other popular traditional methods (two-interval forced-choice, two-down/one-up and maximum-likelihood procedures) and is shown to yield similar thresholds and be more efficient.