Hearing impairment is a condition which affects many New Zealanders. The World Health Organization estimates that by the year 2050, 1 in every 4 people worldwide will suffer from a hearing impairment of some form (World Health Organization, 2021). As hearing impairment has been found to have negative consequences for both individuals and society at large, having widely available hearing screening tools is of growing importance.

While traditional audiological testing is the gold standard for detecting a hearing impairment, this is not always available – particularly in rural or third world countries. As well as this, the recent outbreak of COVID-19 has highlighted the need of alternative testing methods which can be done in a socially-distanced manner (De Sousa, Smits, et al., 2020).

This thesis looks to improve one such method of contactless testing available in New Zealand known as the New Zealand Hearing Screening Test, which uses a New Zealand English digit triplet test. Traditionally this and other digits-in-noise tests have used diotic stimuli (where identical stimuli are presented to both ears) and have been scored by triplet (where all three numbers in the triplet must be correctly entered). The present study investigated the use of antiphasic stimuli (where the polarity of the speech is reversed in one ear) which was shown by De Sousa, Swanepoel, et al. (2020) to improve the sensitivity and specificity of digits-in-noise testing. This study also investigated whether scoring by individual digit rather than digit triplet could also improve the ability of the test to distinguish between people with normal hearing and those with hearing impairment.

Our results found that similar to De Sousa, Swanepoel, et al. (2020), the use of antiphasic stimuli increased the sensitivity and specificity of the New Zealand English digit triplet test from 94% and 88% to 95% and 90% respectively. However, scoring by digit rather than triplet was not found to improve test performance.