Biomedical Engineering for Cochlear Implants

Research Overview

In a normal hearing individual, there are some 15,000 hair cells lining the cochlear, stimulated by movement from sound waves; and up to 50,000 spiral ganglion cells (neural cells) that translate this information to the brain. A cochlear implant recipient has a specialised electrode array located within their cochlea. This array uses only 22 electrodes to bypass the failed hair cells and stimulate the remaining spiral ganglion cells in the cochlear - an incredible feat.

This 'electro-neural interface' is one of the bottlenecks surrounding the provision of hearing for those with a cochlear implant. It is not surprising then, to consider there are still many avenues left to be explored to further improve this area. Being a chronically implanted device, any changes to the cochlear implant require a bio safety assessment before they can be implemented in the device and the clinic.

This project works toward improving the safety, efficiency and efficacy of electrical stimulation of the electrode-neural interface, in particular that of the auditory nerve. The team works closely with engineers and scientists at Cochlear Ltd to enable knowledge gained to be applied to the device.


Carrie Newbold, Senior Research Fellow,

Dimitra Stathopoulos, Senior Research Assistant,


Cochlear Ltd

Biotectix LLC

Royal Victorian Eye and Ear Hospital, Melbourne

Department of Chemical and Biomolecular Engineering, University of Melbourne

Department of Microbiology, University of Melbourne

Research Outcomes

Publications, patents and commercial-in-confidence Technical Reports.

Research Publications

Mergen S, Johnston B, Cowan R, Newbold C 2016 Photoresist-less patterning of silicone substrates for thick film deposition Journal of Manufacturing Processes 22: 21-25.

Stathopoulos D, Chambers S, Adams L, Robins-Browne R, Miller C, Enke Y, Wei B, O’Leary S, Cowan R, Newbold C 2015 Meningitis and a safe dexamethasone-eluting intracochlear electrode array Cochlear Implants International 16(4):201-207.

Newbold, C., Risi, F., Hollow, R., Yusof, Y. and Dowell, R. 2015 Long-term electrode impedance changes and failure prevalence in cochlear implants International Journal of Audiology: 1-8.

Stathopoulos, D., Chambers, S., Enke, Y. L., Timbol, G., Risi, F., Miller, C., Cowan, R. and Newbold, C. 2014 Development of a safe dexamethasone-eluting electrode array for cochlear implantation Cochlear Implants International 15(5): 254-263.

Newbold, C., Farrington, A., Peters, L., Cowan, R. and Needham, K. 2014 Electropermeabilization of adherent cells with cochlear implant electrical stimulation in vitro Audiology and Neurootology 19(5): 283-292.

Newbold, C., Mergen, S., Richardson, R., Seligman, P., Millard, R., Cowan, R. and Shepherd, R. 2014 Impedance changes in chronically implanted and stimulated cochlear implant electrodes Cochlear Implants International 15(4): 191-199.

Agrawal V, Newbold C 2011 Computer modelling of the cochlea and the cochlear implant: a review Cochlear Implants International 13(2): 113-123.

Newbold C, Richardson R, Millard R, Seligman P, Cowan R, Shepherd R 2011 Electrical stimulation causes rapid changes in electrode impedance of cell-covered electrodes Journal of Neural Engineering 8:036029.

Newbold C, Richardson R, Millard R, Huang C, Milojevic D, Shepherd R, Cowan R 2010 Changes in biphasic electrode impedance with protein adsorption and cell growth Journal of Neural Engineering 7:056011.

Xu,J, Briggs R, Tykocinski M, Newbold C, Risi F, Cowan R 2009 Seeing electrode Carrie Newbold Application for Promotion May 2016 19

movement in the cochlea Micro-focus fluoroscopy — A great tool for electrode development Cochlear Implants International; 10(S1):115-119.

Richardson R, Thompson B, Moulton S, Newbold C, Lum M, Cameron A, Wallace G, Kapsa R, Clark G, O'Leary S The effect of polypyrrole with incorporated neurotrophin-3 on the promotion of neurite outgrowth from auditory neurons Biomaterials 2007; 28(3):513-23.

Newbold C, Richardson R, Huang C, Milojevic D, Cowan R, Shepherd R, 2004 An in vitro model for investigating impedance changes with cell growth and electrical stimulation: implications for cochlear implants Journal of Neural Engineering 1:218-227.

Zhou, D., G.G. Wallace, G.M. Spinks, L. Liu, R. Cowan, E. Saunders, and C. Newbold, Actuators for the cochlear implant Synthetic Metals, 2003. 135(1-3): p. 39-40.

Newbold C, Saunders E, Tykocinski M, Cohen L, Knight M, Cowan R, 2001 Nucleus 24 Contour Array: the Melbourne experience, Australian and New Zealand Journal of Audiology 23(2):127 (XXVI International Congress of Audiology, Melbourne, 17-22 March 2002) (published abstract).

Research Projects

This Research Group doesn't currently have any projects

Faculty Research Themes


School Research Themes

Neuroscience & Psychiatry

Key Contact

For further information about this research, please contact Senior Research Fellow Dr Carrie Newbold

Department / Centre


Unit / Centre

Biomedical Engineering for Cochlear Implants

MDHS Research library
Explore by researcher, school, project or topic.