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Title: Signal processing of the auditory event-related potential in major psychotic illness
Author: Glabus, Michael Francis
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1995
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The P300 waveform of the auditory event-related potential (ERP) was evaluated in studies which examined measurement methodology and which analysed the separate sub-components of the waveform in a group of patients with schizophrenia and manic depressive illness. Two simulation studies were carried out. One was designed to evaluate a new objective method for measuring P300 latency, the other applied the technique of latency corrected averaging to P300 measurement. A model for the P300 is described which allows the time domain behaviour of the waveform to be predicted when it is subjected to the different high-pass filters used in clinical studies. The first clinical study was a detailed investigation on the measurement methodology in clinical studies of the auditory P300. The second clinical study used novel auditory stimuli as a means of separating the sub-components of the P300 complex. Three clinical tests were used based on the standard auditory "oddball", a standard auditory oddball with additional "distracting" novel stimuli, and a passive paradigm using novel stimuli. The use of Slow Wave as an index of task difficulty was examined. Twenty-eight controls, 29 schizophrenics and 28 subjects with bipolar depression were studied. The results from these experiments showed that abnormalities of P300 sub-components in the schizophrenic group are enhanced when using distracting stimuli and that these differences are present even in passive orienting. The bipolar group also showed abnormal P300 sub-components in responses to the distraction task. These results could imply a more widespread disruption in underlying brain structures in schizophrenia than bipolar depression. Used in conjunction with brain perfusion images derived from single photon emission tomography (SPET), the paradigms described have shown great potential for locating the underlying brain structures involved in the genesis of P300, and how they are affected in abnormal pathological states.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available