Evaluation of matched compressors on speech intelligibility of bimodal listeners

The clinical performance of patients implanted with a cochlear implant (CI) on one side and wearing a hearing aid (HA) on the other side shows large inter-individual differences. A recent study by Veugen et al. (2016) addressed this issue of bimodal listening by matching the time constants and the number of compression channels for the automatic gain control (AGC) of the HA to the CI subjects using Advanced Bionics CI and Phonak HA. This study found a statistically significant benefit of the matched condition. The aim of this study was to reproduce the outcome of a bimodal benefit for matched AGC settings with a different CI (Cochear Ltd.) and HA manufacturer (GN Hearing) in order to generalize the previous findings.

Fifteen patients implanted with a CI on one side and using a HA on the other side were measured. The study consisted of three visits with two intervals in which the subject become familiar either with the clinical baseline or the AGC matched CI and HA fitting. Freiburg monosyllabic words were conducted at a soft (50 dB SPL) and conversational presentation level of 65 dB SPL. The speech in noise was conducted using the Oldenburg adaptive sentence test.

No significant differences in speech intelligibility between the clinical fitting and the condition with matched AGC of the cochlear implant speech processor and hearing aid were matched were found.

Even through this study used the same time constants to match the devices, the difference of signal processing in the devices used for this study might prevent the generalization of the previous results.

Veugen et al., 2016. Matching automatic gain control across devices in bimodal cochlear implant users. Ear and hearing 37, 260 – 270

Publication History

Publication Date:
23 April 2019 (online)