Development of an Australian behavioural method for assessing listening task difficulty at high speech intelligibility levels

Objective: To develop and validate an Australian version of a behavioural test for assessing listening task difficulty at high speech intelligibility levels. 

Design: In the SWIR-Aus test, listeners perform two tasks: identify the last word of each of seven sentences in a list and recall the identified words after each list. First, the test material was developed by creating seven-sentence lists with similar final-word features. Then, for the validation, participant’s performance on the SWIR-Aus test was compared when a binary mask noise reduction algorithm was on and off. 

Study sample: All participants in this study had normal hearing thresholds. Nine participants (23.8–56.0 years) participated in the characterisation of the speech material. Another thirteen participants (18.4–59.1 years) participated in a pilot test to determine the SNR to use at the validation stage. Finally, twenty-four new participants (20.0–56.9 years) participated in the validation of the test. 

Results: The results of the validation of the test showed that recall and identification scores were significantly better when the binary mask noise reduction algorithm was on compared to off. 

Conclusions: The SWIR-Aus test was developed using Australian speech material and can be used for assessing task difficulty at high speech intelligibility levels.