Discrimination loss vs. SRT: A model-based approach towards harmonizing speech test interpretations

TL;DR

This study introduces a model-based method to estimate speech recognition thresholds from clinical data, aiming to harmonize speech test interpretations and improve understanding of discrimination loss versus SRT.

Contribution

A novel, model-based SRT estimation procedure that handles incomplete data and compares different estimation methods for clinical speech test analysis.

Findings

The model-based SRT estimation provides accurate results with some slope deviations.

Different interpretation modes reveal variations in supra-threshold deficits.

All methods are affected by uncertainty in word recognition scores.

Abstract

Objective: Speech tests aim to estimate discrimination loss or speech recognition threshold (SRT). This paper investigates the potential to estimate SRTs from clinical data that target at characterizing the discrimination loss. Knowledge about the relationship between the speech test outcome variables--conceptually linked via the psychometric function--is important towards integration of data from different databases. Design: Depending on the available data, different SRT estimation procedures were compared and evaluated. A novel, model-based SRT estimation procedure was proposed that deals with incomplete patient data. Interpretations of supra-threshold deficits were assessed for the two interpretation modes. Study sample: Data for 27009 patients with Freiburg monosyllabic speech test (FMST) and audiogram (AG) results from the same day were included in the retrospective analysis. Results: The model-based SRT estimation procedure provided accurate SRTs, but with large deviations in the estimated slope. Supra-threshold hearing loss components differed between the two interpretation modes. Conclusions: The model-based procedure can be used for SRT estimation, and its properties relate to data availability for individual patients. All SRT procedures are influenced by the uncertainty of the word recognition scores. In the future, the proposed approach can be used to assess additional differences between speech tests.