Improving acquisition of auditory evoked potentials for clinical diagnosis and monitoring
Improving acquisition of auditory evoked potentials for clinical diagnosis and monitoring
Auditory evoked potentials (AEPs) represent the response of the brain to an auditory stimulus and they are recorded using electrodes placed on the scalp. They have a number of clinical applications including estimating hearing threshold, detection of pathology in the auditory pathway and possibly indicating depth of anaesthesia during surgical procedures. The aim of this study was investigate new methods to improve the acquisition of AEPs for clinical monitoring purposes.
The approach adopted has been primarily to optimise the stimulation used to elicit AEPs, rather than focusing on signal processing to improve extraction of the signal from background noise. New stimulation methods to acquire AEPs have been investigated using normative experiments. Two such experiments investigated three possible methods to improve acquisition of the AEP known as the Middle Latency Response (MLR). These methods were a) varying conventional stimulation rate b) using high maximum length sequence (MLS) stimulation rates (a form of pseudorandom binary sequence) and c) using chirp stimuli (rising frequency sweeps) designed to compensate for frequency dispersion on the basilar membrane. The use of chirp stimuli presented to high MLS stimulation rates appears to reduce the acquisition time of the MLR significantly compared to conventional stimulation methods.
The use of band-limited chirp (rising frequency sweeps across a limited frequency range) stimuli to obtain the Auditory Brainstem Response (ABR) was also investigated. The use of such stimuli appear to produce better objective estimates of low frequency thresholds than have been reported for other transient stimuli such as tone bursts. This is consistent with the chirp stimuli improving the neural synchrony of low frequency responses, although it may be a consequence of the spread of excitation to high frequencies. As the stimuli have significant spectral spread, their clinical application to assess frequency specific thresholds may be limited.
University of Southampton
Bell, Steven Lewis
3400f5ed-3d2e-462a-ba9f-2857a4393aa8
2003
Bell, Steven Lewis
3400f5ed-3d2e-462a-ba9f-2857a4393aa8
Bell, Steven Lewis
(2003)
Improving acquisition of auditory evoked potentials for clinical diagnosis and monitoring.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Auditory evoked potentials (AEPs) represent the response of the brain to an auditory stimulus and they are recorded using electrodes placed on the scalp. They have a number of clinical applications including estimating hearing threshold, detection of pathology in the auditory pathway and possibly indicating depth of anaesthesia during surgical procedures. The aim of this study was investigate new methods to improve the acquisition of AEPs for clinical monitoring purposes.
The approach adopted has been primarily to optimise the stimulation used to elicit AEPs, rather than focusing on signal processing to improve extraction of the signal from background noise. New stimulation methods to acquire AEPs have been investigated using normative experiments. Two such experiments investigated three possible methods to improve acquisition of the AEP known as the Middle Latency Response (MLR). These methods were a) varying conventional stimulation rate b) using high maximum length sequence (MLS) stimulation rates (a form of pseudorandom binary sequence) and c) using chirp stimuli (rising frequency sweeps) designed to compensate for frequency dispersion on the basilar membrane. The use of chirp stimuli presented to high MLS stimulation rates appears to reduce the acquisition time of the MLR significantly compared to conventional stimulation methods.
The use of band-limited chirp (rising frequency sweeps across a limited frequency range) stimuli to obtain the Auditory Brainstem Response (ABR) was also investigated. The use of such stimuli appear to produce better objective estimates of low frequency thresholds than have been reported for other transient stimuli such as tone bursts. This is consistent with the chirp stimuli improving the neural synchrony of low frequency responses, although it may be a consequence of the spread of excitation to high frequencies. As the stimuli have significant spectral spread, their clinical application to assess frequency specific thresholds may be limited.
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Published date: 2003
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Local EPrints ID: 464968
URI: http://eprints.soton.ac.uk/id/eprint/464968
PURE UUID: 7a69384f-2a83-4fc1-bff0-158c8773617e
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Date deposited: 05 Jul 2022 00:14
Last modified: 16 Mar 2024 19:51
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Author:
Steven Lewis Bell
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