Evaluation of a synthetic version of the digits-in-noise test and its characteristics in CI recipients

Abstract

Objective: The goal of this study was the evaluation of a synthetic version of the Digits-in-Noise (DiN) in participants with normal hearing. Additionally, the basis characteristics of the DiN in CI recipients were investigated.

Design and study sample: Twenty participants with normal hearing and 21 CI recipients with a Nucleus®-System ran two to three adaptive and up to five fixed measurements. Afterwards the discrimination function was measured with fixed signal-to-noise ratios.

Results: All subjects were able to perform the DiN within three minutes per test run. The median speech reception threshold (SRT) for the NH was -8.1 dB_SNR, with a median steepness of 23%/dB_SNR. The median absolute test-retest difference in the NH group was 0.4 dB (range: 0 to 1.5 dB). In the CI group, the SRTs range from -6.6 to +12.4 dB_SNR with a median test-retest difference of 0.4 dB (range: 0 to 6.1 dB).

Conclusion: The synthetic DiN is a valuable complement of the audiometric test battery in CI recipients. The excellent applicability is also particularly helpful in poor performing CI recipients. With its small time exposure, it is a time- and cost-saving test, which could also be used at home via app to check the individual hearing success.

Keywords: Digits-in-Noise test; Speech perception in noise; cochlear implant; discrimination function; people with normal hearing.