Effects of Spectral Distortion on Speech Intelligibility

Abstract

Fine-structure cues play a role in understanding speech in fluctuating noise, but do not appear to be accessible to listeners with sensorineural hearing loss (SNHL) (Lorenzi et al., 2006). Moore (2008) proposed that fine-structure cues may help mitigate deleterious effects of multichannel compression. Recent evidence suggests that effects of compression are not influenced by fine-structure and detailed spectral information (Hopkins et al., 2012). The present study measured impact of multichannel compression and the role of fine-structure. Two indices were considered to quantify spectral distortion introduced by compression. Speech understanding in noise was measured in normal-hearing subjects. Fine-structure was removed from the signal and spectral smearing was used to simulate broadened auditory filters characteristic of SNHL. Fast multichannel compression reduced intelligibility compared to single-channel and no compression. There was no interaction between compression and fine-structure or smearing. The results support Hopkins et al. (2012), and do not support Moore’s (2008) hypothesis.