Sound localization with bilateral bone conduction stimulation: Influence of stimuli and simulated flat sensorineural hearing loss

Bone conduction (BC) hearing aids have been widely used in the clinical treatment of conductive and mixed hearing loss. Part of mixed hearing loss is sensorineural hearing loss (SNHL) and sound localization with pure SNHL and BC stimulation has not yet been clarified. In the present study, flat SNHL was simulated by continuous broadband pink noise, and the effects of level and signal audibility and frequency content of the stimuli on the localization performance with bilateral BC stimulation were investigated. The results showed that the localization was affected by both interaural threshold differences and frequency content of the stimulation. When the simulated interaural threshold difference was less than 20 dB, the localization performance was not significantly different from subjects with normal hearing. Results with broadband and high-frequency narrow and wideband stimuli were significantly better than narrow or wideband low-frequency stimuli. However, when the interaural threshold difference was more than or equal to 20 dB, the localization was shifted towards the good ear, resulting in a significant decline in localization ability. Moreover, the localization performance with wideband high-frequency stimuli was better than the other four stimuli. For simulated mild-to-moderate flat SNHL, as long as the stimuli was audible, there was no correlation between localization ability and level of hearing loss, while interaural threshold difference resulted in skewed localization.