The Self-Assessed Békesy Procedure: Validation of a Method to Measure Intelligibility of Connected Discourse

Abstract

In clinical practice and research, speech intelligibility is generally measured by instructing the participant to recall sentences. Although this is a reliable and highly repeatable measure, it cannot be used to measure intelligibility of connected discourse. Therefore, we developed a new method, the self-assessed Békesy procedure, which is an adaptive procedure that uses intelligibility ratings to converge to a person’s speech reception threshold. In this study, we describe the new procedure and the validation in young, normal-hearing listeners. First, we compared the results on the self-assessed Békesy procedure to a recall procedure for standardized sentences. Next, we evaluated the inter- and intrasubject variability of our procedure. Furthermore, we compared the thresholds for sentences in three masker types between the self-assessed Békesy and a recall procedure to verify if these procedures resulted in similar conclusions. Finally, we compared the thresholds for two types of sentences and commercial recordings of stories. In general, the self-assessed Békesy procedure is shown to be a valid and reliable procedure as similar thresholds (difference < 1 dB) and test–retest reliability (< 1.5 dB) were observed compared with standard speech audiometry tests. In addition, the time efficiency and similar differences between maskers to a recall procedure support the potential of this procedure to be implemented in research. Finally, significant differences between the thresholds of sentences and connected discourse materials were found, indicating the importance of controlling for differences in intelligibility when presenting these materials at the same signal-to-noise ratios or when comparing studies.