The Concurrent OLSA test: A method for speech recognition in multi-talker situations at fixed SNR

TL;DR

This paper introduces a multi-talker speech recognition paradigm using attentional processes to measure recognition scores at high SNRs, simulating group conversations with overlapping speech and dual tasks.

Contribution

It presents a novel multi-talker paradigm with adjustable overlap times to study speech recognition and cognitive load in multi-talker scenarios.

Findings

Recognition scores decrease with increased overlap time

Dual task effects indicate higher cognitive load

Significant differences in recognition performance across conditions

Abstract

A multi-talker paradigm is introduced that uses different attentional processes to adjust speech recognition scores with the goal to conduct measurements at high signal-to-noise ratios. The basic idea is to simulate a group conversation with three talkers and a participant. Talkers alternately speak sentences of the German matrix test OLSA. Each time a sentence begins with the name "Kerstin" (call sign), the participant is addressed and instructed to repeat the last words of all sentences from that talker, until another talker begins a sentence with "Kerstin". The alternation of the talkers is implemented with an adjustable overlap time that causes an overlap between the call sign "Kerstin" and the target words to be repeated. Thus, the two tasks of detecting "Kerstin" and repeating target words are to be processed at the same time as a dual task. The paradigm was tested with 22 young normal-hearing participants for three overlap times (0.6 s, 0.8 s, 1.0 s). Results for these overlap times show significant differences with median target word recognition scores of 88%, 82%, and 77%, respectively (including call sign and dual task effects). A comparison of the dual task with the corresponding single tasks suggests that the observed effects reflect an increased cognitive load.