National Institute of Health 
Contract NIH-N01-DC-3-1005

Protective effects of patterned electrical stimulation
on the deafened auditory system

The goal of this contract is to develop methods of protecting the remaining portions of the auditory system from degeneration after loss of hair cells and to improve its effectiveness in extracting information provided by auditory prostheses. We have taken a broad neurobiological approach to this goal in order to study both the short and long-term response of the auditory system to loss of hair cells and the subsequent introduction of afferent input via an auditory prosthesis. Our studies are divided into three major areas of investigation:

(a) The neurophysiological and neuroanatomical response of spiral ganglion neurons (SGNs) and the central auditory system (CAS) following chronic intracochlear electrical stimulation in combination with neurotrophic support of the auditory nerve. This work is designed to investigate whether electrical stimulation and chronic administration of neurotrophins act in synergy to promote auditory nerve (AN) survival in both guinea pig and other mammalian models of sensorineural hearing loss (SNHL). This work will also provide insight into the role of neurotrophins in improving synaptic efficiency in the deafened auditory pathway.

(b) The neurophysiological and neuroanatomical response to prolonged electrical stimulation of the auditory nerve following a neonatal SNHL. This work is designed to provide insight into the protective effects of electrical stimulation on SGNs and the plastic response of the CAS to temporally challenging stimuli presented chronically to one or two sectors of the AN. This work will also examine the ultrastructural changes evident at the AN/cochlear nucleus synapse in response to a neonatal SNHL and to chronic electrical stimulation of the AN.

(c) The application of cell based therapies for rescue and regeneration of SGNs following SNHL. These studies are designed to provide insight into the potential clinical application of cell-based therapies in the severe and profoundly deaf prior to cochlear implantation.

While these studies are designed to provide insight into the plastic response of the deafened auditory pathway to re-activation via an auditory prosthesis, a major objective of this work is to apply our findings to the clinical environment.

Research Team

Principal Investigator:

Associate Professor 
Robert K. Shepherd

 


Contract workshop with staff and Melbourne 
based consultants, December 2003 

 

 

 

Co-Investigators

Professor Dexter Irvine 

Dr Jin Xu

 

 

 

Research Staff: 

Ms Anne Coco 

Ms Lauren Donley

 

Dr James Fallon 

Dr Lisa Gillespie

 

Dr Justin Tan

 

 

 

 

Engineer:

Mr Rodney Millard

 

Histologist: 

Ms Maria Clarke

 

Electrode Fabricator:

Ms Helen Feng

 

 

 

 

Post Graduate Students: 

Dr Patricia Hurley

Ms Bryony Coleman

Honours Students:

Ms Ricky Minter

 

UROP Students:

Mr David Perry

 

 

TWJ Fellow

Dr Steven Backhouse

 

 

 

 

 

 

Collaborators:

Dr Janine Clarey

Dr Stephen O'Leary

 

 

Dr Tony Paolini

 

 

 

 

 

 

Consultants: 

Dr Jeremy Crook

Dr Henrik Dahl

 

 

Dr Michelle de Silva

Dr Alan Mackay-Sim

 

 

Dr John Mariadason

Dr Natalie Rickard

 

 

Dr Edwin W. Rubel

Dr David Ryugo 

 

 

 

Dr Peter Seligman

 

 

 

Quarterly Progress Reports
 

 

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