Contribution
A Binaural Cue Transformation Method to Preserve Spatial Release From Masking in Listeners With Impaired ITD Processing
* Presenting author
Abstract:
In acoustically challenging situations, speech intelligibility can be improved when talkers are spatially separated because of the spatial release from masking resulting from an exploitation of Interaural Time and Level Differences (ITDs and ILDs). Hearing impaired listeners, however, can have difficulties exploiting ITDs whereas the ILD perception is often unimpaired. Therefore, we propose a method to transform low-frequency ITDs into ILDs to improve speech intelligibility. To test the transformation method, speech reception thresholds (SRTs) of normal-hearing listeners were measured for different binaural cue manipulations. The SRTs improved by 7 dB when the target and interfering talkers were spatially separated due to the known beneficial spatial release from masking. When the ITDs were removed from the signals to simulate a hearing impairment, the SRTs were about 3 dB worse than when ITDs and ILDs were available to the listener. Applying the proposed transformation to the signals without ITDs, improved the SRTs again to almost the same level, as if ITDs and ILDs were both available. These findings suggest that the spatial benefit in speech perception is preserved when converting ITDs to ILDs, which could aid hearing impaired listeners when such a conversion is implemented in hearing aids and cochlear implants.