Localisation in Noise, SNHL, and Hearing Aids Stuart Gatehouse Everyday listening often involves integration of auditory information arriving at the two ears to optimise hearing abilities. Specific binaural effects include the improvement in speech identification abilities over and above monaural listening, and processes which underpin the localization of sounds. Our programme investigates the psychophysical bases of these phenomena and the extent to which conductive and sensorineural hearing loss compromise these abilities, in addition to the efficacy of management for these conditions. Current experiments concern localisation in the frontal horizontal plane and demonstrate the extent to which interaural time delay (ITD) and interaural level difference (ILD) cues are compromised by the presence of noise for listeners with normal hearing and SNHL and the extent to which listeners can combine the two types of cues. A further experiment investigates the relationship between low frequency sensorineural hearing loss and the use of ITD cues for unaided conditions and a variety of conditions involving amplification. The results show that localisation abilities based upon ITD cues are degraded in sensorineural hearing loss in systematic ways and are not completely restored by the provision of amplification. Approximately half of the deficit in localisation ability results from audibility reductions in SNHL, with the remainder attributed to "distortions" accompanying SNHL. Long-term testing following provision of bilateral amplification shows that our results are not a simple reflection of unfamiliar access to the ITD cues. |