Medicine, Dentistry and Health SciencesDepartment of Otolaryngology

Background

While many cochlear implant users perform well in ideal listening conditions, performance in noisy or complex listening environments with sound sources arriving from different directions often remains challenging. This can be greatly improved by using two cochlear implants, one in each ear, rather than just one. However, not all the benefits of using two ears that are available with normal hearing have been observed in bilateral cochlear implant users. The aim of this project is to better understand how electrical stimulation parameters and sound coding strategies can be optimised to achieve maximum benefit from using both ears.

Research Aims

• To use psychophysical methods to assess true binaural processing abilities in CI users, which may lead to benefits beyond those derived from dual monaural device use

• To determine whether bilateral CIs offer advantages in complex listening environments as they do in normal hearing listeners, and characterize dependency of those advantages on level and timing cues available in the electrical signal

• To determine how subject-specific characteristics impact on the ability to restore binaural hearing, and develop subject appropriate sound coding strategies and clinical mapping methods that are optimised for bilateral device use

• To develop computational models that describe psychophysical and neural response data for bilateral acoustic and electrical stimulation, in order to design improved stimulation algorithms with enhanced binaural cues for cochlear implant users

People

• Dr. Richard van Hoesel

Collaborators

• A.Prof. R. Litovsky (University of Wisconsin)
• Dr.K.Gordon (The Hospital for Sick Children, Toronto)

Recent Publications/Presentations

van Hoesel, R.J.M., (2008) “Observer weighting of level and timing cues in bilateral cochlear implant users”, J.Acoust.Soc.Am (in press)

van Hoesel, R.J.M. (2008) "Binaural jitter with cochlear implants, improved interaural time-delay sensitivity, and normal hearing", PNAS, 105:E51; doi:10.1073/pnas.0801746105

van Hoesel, R., Böhm, M., Pesch, J., Vandali, A., Battmer, R-D, Lenarz, T. (2008) “Binaural speech unmasking and localization in noise with bilateral cochlear implants using envelope and fine-timing based strategies”, J.Acoust.Soc.Am., 123(4), 2249-2263.

Jones, G, van Hoesel, R., Litovsky, R (2008) “Effect of channel interactions on sensitivity to binaural timing cues in electrical hearing”, J.Acoust.Soc.Am. 123 (5), 3055

Gordon, K. A., Papsin, B.C., Valero, J., van Hoesel, R. (2008). “Abnormal timing delays in auditory brainstem responses evoked by bilateral cochlear implant use in children.” Otol Neurotol. 29 (2), 193-198

van Hoesel (2007). "Sensitivity to binaural timing in bilateral cochlear implant users". J.Acoust.Soc.Am. 121 (4), 2192-2206.

van Hoesel, R., Lenarz, T., Battmer, R-D., Beckschebe, J., Böhm, M., (2005). “Loudness-mapping effects on speech intelligibility with bilateral cochlear implant users”, Ear and Hear., 26(4):381-388.

van Hoesel, R.J.M. (2004). “Exploring the benefits of bilateral cochlear implants”, Audiol. & Neuro-Otol., Vol. 9, No. 4, pp. 235-247.

van Hoesel, R.J.M. and Tyler, R.S., (2003). “Speech-perception and localization with bilateral cochlear implants”, J.Acoust.Soc.Am., 113(3), 1617:1630.

Funding

The HEARing CRC, Australia.