Integrated Digit-in-Noise Test: A Rapid Screening Tool for Hearing and Cognitive Function

TL;DR

The iDIN test quickly screens for both hearing loss and cognitive decline in older adults using digit sequences in noise.

Contribution

The iDIN test is the first to simultaneously assess and differentiate hearing and cognitive function using digit-in-noise sequences.

Findings

The iDIN test detected hearing loss with a cutoff of -7.7 dB SNR (sensitivity 0.85, specificity 0.73).

Cognitive screening via SRT3b-3 showed optimal cutoffs of 3.3 dB for MCI and 5.5 dB for dementia.

SRT3b-3 was not correlated with hearing levels, supporting its use for cognitive screening in hearing-impaired individuals.

Abstract

A rapid and easy-to-administer screening tool is essential for community-based detection of hearing loss and cognitive decline. The Integrated Digit-in-Noise Test (iDIN) extends the traditional Digit-in-Noise Test (DIN) by incorporating 2- to 5-digit sequences, as the only test to simultaneous assess and differentiate hearing and cognition. Speech Reception Thresholds (SRTs) are measured as the signal-to-noise ratio (SNR) at which 50% of digits are correctly identified. Specifically, 3-digit SRTs are used for hearing screening, while the difference between backward and forward 3-digit SRTs (SRT3b-3) serves as an indicator of cognitive function. In this study, 601 community-dwelling participants with potential but undiagnosed hearing loss were recruited (mean age 76.0 ± 8.8 years; education 6.4 ± 4.4 years; MoCA 21.5 ± 6.4). In terms of hearing screening, the average 3-digit SRT was -4.3 ± 7.0 dB SNR, with a cutoff of -7.7 dB SNR for hearing loss detection (35 dB HL in better ear) (sensitivity 0.85, specificity 0.73). For cognitive screening, the mean SRT3b-3 was 5.03 ± 7.32 dB SNR. Using MoCA thresholds of 21/22 for MCI, the optimal SRT3b-3 cutoff was 3.3 dB (sensitivity 0.74, specificity 0.76); for dementia (MoCA 15), the cutoff was 5.5 dB (sensitivity 0.83, specificity 0.77). No significant correlation was found between SRT3b-3 and better ear hearing levels, indicating that iDIN can effectively be used for cognitive screening in older adults with hearing impairment. In conclusion, iDIN shows promise as a quick, dual-purpose screening tool for early detection of hearing and cognitive issues in community settings.