Development and validation of a digits-in-noise hearing test in Persian.

Objective: The prevalence of unrecognised and late-diagnosed hearing loss is higher in low- and middle-income than in high-income countries, due in part to lack of access to hearing services. Because hearing screening is important for early identification of hearing loss, development of an accessible, self-screening test that can detect hearing loss reliably and quickly would provide significant benefits, especially for underserved populations. This study aimed to develop and validate a new version of the digits-in-noise (DIN) test for Persian speaking countries.

Design: Recordings of Persian digits 0-9 were binaurally presented in broadband speech-shaped noise. Using fitted speech intelligibility functions, digits were homogenised to achieve equal perceptual difficulty across stimuli. The evaluation was established by reference to existing English DIN tests.

Study Sample: Thirty Persian speaking young adults with normal hearing thresholds (≤20 dB HL, 0.25-8 kHz).

Results: Speech intelligibility functions produced a mean speech reception threshold (SRT) of -7.7 dB, corresponding closely to previously developed DIN tests. There was no significant difference between test and retest SRTs, indicating high reliability of the test. Our findings suggest that language-specific factors need to be considered for cross-language comparison of DIN-SRTs.

Conclusion: This study introduces a convenient tool for future hearing screening in Persian speaking countries with limited access to audiology services.