 AAAF News
|
2008 Summer Research Fellowship
 Christopher Spankovich, AuD, MPH
Doctoral Student, Vanderbilt University
Title: Noise Exposure: Acute Insults and Delayed Neurodegenerative Outcomes
Mentor: Sharon Kujawa, PhD, Massachusetts Eye & Ear Infirmary
Project Description: Although SGC death takes many months to appear, there are clear-cut signs of acute neuropathy within the cochlear epithelium in the hours and days following exposure. To examine this degeneration, two primary methods of investigation will be utilized. First, confocal microscopy (Aim 1) will be performed to track degeneration over post-exposure time as it progresses from synapse, to peripheral axon, to cell body. Progressive terminal degeneration at the first neurochemical synapse will likely have significant functional consequences for stimulus coding and information transfer; this model proves an unusual opportunity to access these events in ears with preserved outer and inner hair cells and good threshold sensitivity. In Aim 2, we will incorporate physiological characterization of these degenerative events, correlating them in time and cochlear location with the pathology. Measurement of threshold and suprathreshold response properties via cochlear DPOAEs and auditory neural CAPs and ABRs will be compared with measures of single-fiber activity from auditory nerve, work already underway by another student in the lab. Together, these measurements will provide insight into the functional state of the remaining synapses.
During the summer fellowship, Chris wil gain hands on experience in characterizing changes in cochlear and auditory nerve responses correlated with underlying histopathology following noise exposure. To date, the physiologic characterizations have focused on threshold sensitivity changes. Chris will extend these characterizations to suprathreshold responses, including an electrophysiologically-based gap detection metric to explore temporal coding in ears with and without noise-induced neurodegeneration (Aim 2). Additionally, he will perform noise exposures and will recover and process tissues for study by histologic and immunohistochemical methods (Aim 1). The data he will collect should provide insight into mechanisms underlying the ongoing neuronal degeneration and functional deficits associated with the degeneration. Chris will also have exposure to other ongoing lab collaborators including an NIH funded project to develop a miniature implantable pump for chronic inner ear drug delivery and study on stereocilia protein turnover in noise-exposed ears.
The intention of this fellowship is to provide experience with the data collection techniques described and instill a greater understanding of methods in measuring cochlear pathology associated with noise exposure and aging. The predicted outcomes are for Chris to significantly contribute to this study, but perhaps more importantly, for Chris to gain knowledge and experience with techniques that will serve him well in his own research.
Acknowledgement: II would like to thank Dr. Sharon Kujawa for providing me the wonderful opportunity to work with her and her colleagues to at Massachusetts Eye and Ear Infirmary and Eaton Peabody Laboratory. In addition, I would like to acknowledge my advisor Linda Hood, PhD for her mentorship and help in making this idea into a reality. Thanks are also extended to my fellow lab mates Andrea Hillock, AuD, Erin Maloff, MS and Heather McCaslin, AuD for all of their support. Finally, I would like to recognize Fred Bess, PhD and Edward Conture, PhD for allowing me to take advantage of this wonderful opportunit
Back
 |