Bilateral cochlear implants (BI-CIs) improve speech understanding and sound localization, but it is unknown whether two ears afford any listening effort benefits to BI-CI listeners. The long term goal is to understand bin- aural (two-ear) benefits in hearing-impaired listeners so that hearing devices are designed not only to maximize speech perception but also minimize listening effort, a dimension of perception that is potentially important. The specific objective of this proposal is to evaluate changes in speech understanding and listening effort in BI-CI listeners for binaural tasks. The central hypothesis is that symmetrical ears improve binaural benefits, but asym- metrical ears limit these benefits. The approach is to combine behavioral measures of perception with pupillom- etry, an objective and physiological measure of listening effort, which has yet to be used as a tool to understand the benefits of two sound inputs in BI-CI listeners. The rationale is that consideration of listening effort and speech perception together can give a more complete picture of real-world listening. Binaural benefits to speech perception and listening effort will be explored in two aims: 1) to determine the extent to which asymmetrical inputs affect perception and listening effort in dichotic listening in BI-CI and normal-hearing listeners and 2) to measure the extent to which BI-CIs improve speech understanding and reduce listening effort with spatial sep- aration of talkers. The contribution of this research is expected to be knowledge of the benefit of binaural hearing to listening effort in BI-CI listeners. This contribution is significant because it is a first step in understanding listening effort and reducing it in the future, particularly in noisy environments, for hearing-impaired listeners. This proposal is innovative because it uses an objective physiologic technique ? pupillometry ? to measure listening effort in CI listeners, and combines binaural hearing and listening effort expertise to examine the ad- vantages of BI-CI listening. The PI of this Mentored Career Development Award is an Au.D.-Ph.D. postdoctoral researcher at the University of Maryland-College Park. The PI will acquire expertise in binaural hearing and listening effort, increase proficiency in the study of CI listeners and the use of CI simulations, develop program- ming skills to design auditory experiments and simulate sound locations, and learn advanced statistical methods under this award. Other training activities include coursework in statistical methods, on-campus seminars, formal training in grant writing, and presenting research at professional meetings. The PI has assembled an interdisci- plinary team of mentors who are experts in the PI?s areas of interest. This mentorship and the mentee?s strong psychoacoustics background will prepare the PI to reach the long-term goals of attaining a tenure-track faculty position and developing an independent, R01-funded research program as a clinician-scientist, focused on im- proving the hearing of individuals with hearing loss in noisy environments.
The proposed research is relevant to public health because understanding bilateral (two-ear) hearing benefits to cochlear implant listeners will guide future clinical practice to optimize hearing outcomes in people with severe- to-profound hearing loss. The proposed research aims to examine the speech perception and listening effort of bilateral cochlear-implant listeners and how ear asymmetry limits these benefits. This research is relevant to NIH?s mission to enhance health and reduce disability, and is also relevant to NIDCD?s mission to improve com- munication in individuals with hearing loss.