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

Abstract

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.

Keywords:

• Speech in noise
• hearing screening test
• hearing loss
• digit triplets
• speech reception threshold

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 Persian is the primary spoken language of an estimated 110 million people worldwide, mainly in Iran, Afghanistan, and Tajikistan, all LMICs. It is also a widely understood language in Persian Gulf countries (e.g., Bahrain, Iraq, Oman, and Yemen).

2 Farsi, Dari, and Tajik are different dialects of Persian languages, meaning that in their written form they all refer basically to one language. Farsi is the spoken language of Iran. Dari is the spoken language of Afghanistan. Tajik is the spoken language of Tajikistan.

Additional information

Funding

This study was supported by National Institutes of Health (NIH) [R21DC016241] and by the Cincinnati Children’s Hospital Research Foundation. David Moore received support from the NIHR Manchester Biomedical Research Centre.