Development and validation of the Italian digit-in-noise test

Objective. This research aims to validate the digits-in-noise (DIN) test for the Italian language and develop a version capable of independently assessing both ears while maintaining acceptable administration times. Methods. Individual digits from 0 to 9 in Italian were recorded and adjusted to equalise recognition probabilities. An iOS application (APP) was developed for the independent ear test using triplets in noise. The application incorporates a new proprietary adaptive procedure developed by Amplifon to minimise the number of steps required to determine the Speech Reception Threshold (SRT). Thirty-nine subjects were recruited for equalisation of digits, 45 normal-hearing and 62 with various degrees of hearing loss for normative-data assessment. Results. The results demonstrate the ability to determine a threshold value for normal hearing consistent with the existing literature and identify threshold values corresponding to the main World Health Organization hearing loss categories. Conclusions. A DIN test for the Italian language has been developed and validated to evaluate the SRT of each ear individually. The adaptive algorithm optimises the necessary steps while maintaining acceptable test duration for both ears. Users can autonomously conduct the test using a standard personal iOS device (tablet or smartphone).