Cochlear implants: A remarkable past and a brilliant future

The Dean's seminar series was established in 2011 to provide the opportunity for distinguished researchers to initiate conversation around relevant high impact research that demonstrates leadership in Engineering and IT innovation. This seminar on cochlear implants is the sixth in the series.

Speaker: Professor Blake Wilson, Co-Director, Duke Hearing Centre, Duke University Medical Centre (DUMC), Durham, NC, USA, Adjunct Professor, Department of Surgery, DUMC, Adjunct Professor, Department of Electrical and Computer Engineering, Duke University.

Abstract

The cochlear implant (CI) is the most successful of all neural prostheses developed to date. It is the most effective in terms of restoration of function, and recipients of CIs outnumber the recipients of all other types of neural prostheses by orders of magnitude.

In this talk, I will:

1. provide a brief history of CIs;
2. present a status report on the design and performance of the present-day CIs;
3. describe two recent advances; and
4. offer my view of the future

With the current CIs most patients can understand speech presented in quiet conditions with their restored hearing alone. However, speech understanding in noise is difficult for even the best-performing patients and music reception is far below normal for almost all patients. The major factors in these outcomes appear to be:

1. a loss of low-frequency, fine structure information possibly due to the envelope extraction algorithms common to CI signal processing;
2. a limitation in the number of effective channels of stimulation due to substantial overlaps in the electric fields from neighboring electrodes;
3. a lack of sound localization abilities for users of unilateral implants; and
4. processing deficits in the “auditory brain,” especially for patients with poor speech understanding

The two recent advances, bilateral implants and combined electric and acoustic stimulation, have produced large gains in performance, most likely through reducing the negative impacts of factors 1 and 3 and possibly through reducing the negative impact of factor 2.

In addition, new processing strategies designed to improve the representation of fine structure information have extended the range of pitch percepts with CIs and have produced gains in speech reception in noise. Multiple possibilities for further improvements are being investigated, including a new “brain centric” approach to CI designs, which may address factor 4 in the list above. The pace of development has been utterly remarkable since the early days of CIs, and there is no reason at present to think that the pace will decline much if at all in the coming years or that asymptotic performance with CIs has been achieved.

About the Speaker

Prof. Wilson is the Co-Director (with Debara Tucci, M.D.) of the Duke Hearing Center and is an Adjunct Professor in each of two departments at Duke, Surgery and Electrical Engineering. He also is the Chief Strategy Advisor for MED-EL Medical Electronics GmbH of Innsbruck, Austria, and a Senior Fellow Emeritus of the Research Triangle Institute (RTI) in the Research Triangle Park, NC, USA.

He has been involved in the development of the cochlear implant (CI) for the past three decades, and is the inventor of many of the signal processing strategies used with the present-day CIs. One of his papers, in the journal Nature, is the most highly cited publication on studies with CI patients.

He has served as the Principal Investigator for 24 projects, including 13 projects for the United States’ National Institutes of Health. Prof. Wilson and the teams he has directed have been recognized with a high number of awards and honours, most notably the 1996 Discover Award for Technological Innovation (to Wilson); the American Otological Society’s President’s Citation in 1997 for “Major contributions to the restoration of hearing in profoundly deaf persons” (to the RTI team); the 2007 Distinguished Alumnus Award from the Pratt School of Engineering at Duke (to Wilson); and the Neel Distinguished Research Lectureship at the 2008 Annual Meeting of the American Academy of Otolaryngology, Head & Neck Surgery (to Wilson). Prof. Wilson has been the Guest of Honour at ten international conferences, the Chairman for two other international conferences, and a keynote or invited speaker at more than 140 additional conferences.