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Real time application of computers to electrophysiology and diagnostic medicine

Collins, David W.K. (1983) Real time application of computers to electrophysiology and diagnostic medicine. PhD thesis, Murdoch University.

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This research project has been based upon the ability of mini computing systems to accept analogue electrical data in real time and to process the digitised form of the data during and immediately following collection. The clinical areas most suitable for studies of this kind are those in which electrophysiological techniques are already used routinely. The medical specialties which use such techniques are neurology/Where the electroencephalogram (EEC) is well established and cardiology/Where the electrocardiogram (ECG) is in everyday use. If a computer is to be applied in either of these it must be areas able to provide some information of value which is not available from the normal EEG or ECG studies.

In neurology the obvious area for investigation at the time when the project began, in 1976, was in the study of cerebral evoked potentials. Some experimental work had already been done by others and some equipment was commercially available to carry out these studies. However, each item of equipment could only be used to study one modality of evoked potential and the study parameters were usually fixed. The initial aim of the project was to develop a flexible system which could be used in any evoked potential modality and which could vary its data collection parameters to suit changing requirements. Such a system was developed, using a Digital Equipment PDF 11/40 computer and associated peripherals, and was programmed to study evoked potentials from the visual, auditory and somatosensory nervous pathways. The first application was in the study of multiple sclerosis, and it was found that by testing specific patients by using a number of different modalities the diagnostic yield could be significantly increased. The introduction of computer studies of the optokinetic system into the barrage of patient tests increased the diagnostic yield still further. These evoked potential and eye movement techniques have been applied to other neurological disorders such as Huntington's chorea and compressive lesions and have found a psychiatric application in the study of schizophrenic subjects. One of the advantages of the computer based system is the capability of storing data on disk and magnetic tape for a number of years, allowing for further analysis and re assessment of the raw data in the future.

One area of interest in cardiology is in the assessment of the performance of implanted cardiac pacemakers. The EGG monitors in common use do not have the necessary frequency response characteristics to be able to indicate the width of the pacemaker pulse, which is usually in the range of 0.5 to 0.8 ms. Since changes in pulse width are often used to indicate power source failure it is essential that this parameter can be measured easily and reliably. A computer programme was developed for this purpose and was later modified to carry out frontal plane vector analysis of the pacemaker pulse, in order to yield information on the position of the pacing lead within the cardiac muscle.

In the initial planning stages of the project it was decided that the thesis should include a substantial review of basic electrophysiology and of the medical aspects of some of the conditions studied. This is necessary because of the interdisciplinary nature of the work, which requires some understanding of the relevant medicine and physiology as well as physics.

Item Type: Thesis (PhD)
Murdoch Affiliation(s): School of Mathematical and Physical Sciences
Notes: Note to the author: If you would like to make your thesis openly available on Murdoch University Library's Research Repository, please contact: Thank you.
Supervisor(s): Mainsbridge, Bruce and Black, J.L.
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