Auditory brainstem and middle-latency responses with optimized stimuli: experiments and models

The general goal of this thesis is to get a better understanding of the role of cochlear processing for the formation of auditory brainstem and middle latency responses (ABR and MLR). The main emphasis is put on the development and evaluation of an optimized (chirp) stimulus based on the concept of compensation for travel time differences along the basilar membrane. In Ch. 2 it is shown that, due to inclusion of activity from lower-frequency regions, the chirp evokes significantly larger ABR amplitude than the corresponding click. The usefulness of the chirp for retrieving frequency-specific information is investigated in Ch. 3. It is shown that the increased synchrony obtained with the chirp relative to the click stretches over the entire frequency region. In Ch. 4, two alternative chirps are introduced. The level-dependent chirp is found to produce the largest response amplitudes. Chapter 5 introduces a model for the generation of MLR. All nonlinearity in the model is assumed to be restricted to the processing of the stimulus-dependent rate function in the auditory nerve. Predicted potential patterns using clicks and chirps at different levels and stimulation rates are compared with corresponding experimental data. The main characteristics of the data were reflected in the model predictions. The model can also be applied to simulate cochlear hearing losses, in order to understand the effects of hearing impairment on auditory evoked potential generation.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Universität Oldenburg

Year

2003

Author dc:creator

• Fobel, Oliver

• [Keine Schlagwörter von Autor/in vergeben.]

Repository record source_url

http://oops.uni-oldenburg.de/217

OAI identifier oai:identifier

oai:oops.uni-oldenburg.de:217