Thesis defense Snandan Sharma (Donders series 446)

2 October 2020

Promotors: prof. dr. A. van Opstal, prof. dr. E. Mylanus  
Co-promotors: dr. L. Mens, dr. M. van Wanrooij

Towards binaural hearing in bimodal cochlear implant users

Bimodal cochlear implants have become a popular hearing solution for the severe-to-profoundly deaf hearing-impaired individuals with low frequency residual hearing in either one or both of the ears. Bimodal users experience benefits in speech recognition in noisier environments. However, in this work, we learn that they do not have a true binaural hearing and it limits their sound localization ability. We find that the difference in audibility of sounds from either the hearing aid or the implant creates imbalance in overall hearing and that systematically affects the sound localization bias. Several underlying mechanisms tha cause the difference in audibility are addressed by studying sound localization behavior of bimodal and electro-acoustic stimulation users. Lastly, we show the inherent spectral disparity in across the ears in bimodal cochlear implant users may degrade ILD perception.