Effect of asymmetric hearing on spatial selective attention

Abstract

More people are receiving cochlear implant (CIs) to partially restore hearing to both ears, either in cases of bilateral (BI-CI) or unilateral hearing loss (single-sided deafness, SSD-CI). Compared to monaural listening, this usually improves spatial-hearing abilities like sound localization and spatial release from masking (increased speech recognition for a target talker spatially separated from a masker). Yet spatial-hearing benefits with CIs are smaller than with acoustic hearing in both ears, and they appear to diminish with increasing functional asymmetry. We hypothesize that diminished spatial-hearing benefits are partly attributable to non-auditory-exclusive selective-attention abilities, whereby some individuals exhibit particular difficulty attending to a degraded target source in the presence of less degraded interfering source. We present data from several experiments in real and simulated human BI-CI and SSD-CI listeners that support this hypothesis. Measurements include behavioral binaural unmasking of speech and dichotic listening, pupillometry (an objective index of listening effort), and non-auditory cognitive tests. The results suggest that reducing functional asymmetry through novel programming approaches or training might improve spatial-hearing benefits with CIs. [The views expressed in this abstract are those of the authors and do not necessarily reflect the official policy of the Department of War or U.S. Government.]