The current fitting approach adopted for cochlear implant (CI) users falls along the lines of "one-size-fits-all", in that it is assumed that the initial fitting in the clinic should work equally well in all listening environments. Speech coding algorithms and associated parameters (e.g., compression function) are fixed and are not optimized in any way by either the patient or clinician for different listening situations (e.g., quiet, music, noise). The present study addresses this major limitation with the use of a portable research speech processor that allows users to: (a) change MAP parameters based on two different outcome measures (subjective quality ratings and consonant intelligibility) (b) customize the MAP to different listening situations for maximum benefit, and (c) collect feedback and allow the recording of real acoustic signals for further analysis. In this study, unilateral, bilateral and bimodal users will participate in double-blind field trials to assess the true benefit of a speech processor that can be easily customized by the users to fit their needs based on subjective quality ratings or speech intelligibility measures. The overarching hypothesis of this project is that maximum benefit, both in terms of subjective quality and intelligibility, can be obtained when the cochlear implant devices are customized (by the users) to the various listening situations. The outcomes of the field studies will tell us about the difficulties experienced by CI users in real-world situations as well as the value and additional benefit of customizing speech coding algorithms to different environments, all based on feedback from CI users. Such feedback and user interaction can not be gathered using existing commercial processors, yet it is critically needed to move the field forward.

Public Health Relevance

The outcomes of this work can greatly benefit the overall quality of life for a large number of cochlear implant users. Cochlear implant users who are able to communicate effectively in noisy environments have greater opportunity for integration into mainstream education, increase their productivity at home or work and contribute more in the nation's economic growth and competitiveness.

National Institute of Health (NIH)
National Institute on Deafness and Other Communication Disorders (NIDCD)
Research Project (R01)
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Special Emphasis Panel (ZRG1-IFCN-B (02))
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Miller, Roger
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University of Texas-Dallas
Engineering (All Types)
Schools of Engineering
United States
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Yu, Chengzhu; Wójcicki, Kamil K; Loizou, Philipos C et al. (2014) Evaluation of the importance of time-frequency contributions to speech intelligibility in noise. J Acoust Soc Am 135:3007-16
Dorman, Michael F; Loizou, Philip; Wang, Shuai et al. (2014) Bimodal cochlear implants: the role of acoustic signal level in determining speech perception benefit. Audiol Neurootol 19:234-8
Ali, Hussnain; Hazrati, Oldooz; Tobey, Emily A et al. (2014) Evaluation of adaptive dynamic range optimization in adverse listening conditions for cochlear implants. J Acoust Soc Am 136:EL242
Yu, Chengzhu; Wojcicki, Kamil K; Loizou, P C et al. (2013) A NEW MASK-BASED OBJECTIVE MEASURE FOR PREDICTING THE INTELLIGIBILITY OF BINARY MASKED SPEECH. Proc IEEE Int Conf Acoust Speech Signal Process :
Hazrati, Oldooz; Lee, Jaewook; Loizou, Philipos C (2013) Blind binary masking for reverberation suppression in cochlear implants. J Acoust Soc Am 133:1607-14
Chen, Fei; Hazrati, Oldooz; Loizou, Philipos C (2013) Predicting the intelligibility of reverberant speech for cochlear implant listeners with a non-intrusive intelligibility measure. Biomed Signal Process Control 8:311-314
Ali, Hussnain; Lobo, Arthur P; Loizou, Philipos C (2013) Design and evaluation of a personal digital assistant-based research platform for cochlear implants. IEEE Trans Biomed Eng 60:3060-73
Hazrati, Oldooz; Loizou, Philipos C (2013) Reverberation suppression in cochlear implants using a blind channel-selection strategy. J Acoust Soc Am 133:4188-96
Santos, Joao F; Cosentino, Stefano; Hazrati, Oldooz et al. (2013) Objective speech intelligibility measurement for cochlear implant users in complex listening environments. Speech Commun 55:815-824
Hazrati, Oldooz; Loizou, Philipos C (2013) Comparison of two channel selection criteria for noise suppression in cochlear implants. J Acoust Soc Am 133:1615-24

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