[Decision processes at threshold levels during psychoacoustic testing].

Psychoacoustic threshold detection measurements are widely used in clinical and research applications. Usually, a threshold is considered as that intensity of the signal above which the stimulus is detected by the patient and below it will be not. However, this definition is unsatisfactory since there is no such well defined amount of intensity above which the signal suddenly becomes detectable. Rather at intensities close to the "threshold" the patient will be more or less sure to have heard the signal. The more the intensity is increased the more the patient becomes convinced. This paper aims at providing insight into some basics about signal detection close to threshold especially psychometric functions and signal detection theory. It is shown that threshold detection for a given subject not only depends on signal parameters, the subject's co-operation, and on competence of the examiner but also to a great extent on the procedure chosen for estimating the threshold.