The eventual aims of this thesis were threefold. The first was to investigate the patterns of impairments suffered by prosopagnosic subjects, measuring both reaction times and errors, with conclusions being drawn about the heterogeneity of the neurological disorder. Three prosopagnosic subjects were tested on a number of face processing tasks, investigating facial identity matching, facial expression matching and the perception of eye gaze direction. They were found to have different patterns of impairments, reflecting the different causes of their prosopagnosia. The second aim was to investigate cerebral hemispheric asymmetry in normal subjects for both face processing and word processing. Using split- field tachistoscopic presentation of visual stimuli, facial identity matching and facial expression matching were tested, followed by making syntactical judgements for words and finally reading words out loud. No hemispheric differences were found for facial identity or facial expression matching, except where the faces to be matched only comprised internal features, when a right hemisphere advantage was found. The majority of the word processing studies elicited a left hemispheric superiority. It was also shown that words were recognised more easily when they contained fewer syllables, and were more common and familiar to the reader. The third aim of the thesis was to test two additional subjects, who had been shown, on the basis of PET imaging, to have reversed cerebral asymmetry, specifically right hemispheric activity for linguistic tasks. These subjects were tested on the facial identity matching and word processing tasks. No hemispheric advantage for face processing was found, but either a right hemisphere advantage or no hemispheric advantage was found for both of them for word processing, whereas on the same tasks control subjects showed a significant left hemisphere advantage. As a result of this finding, it is suggested that one of the word tasks could possibly be used for further clarification when the results of the WADA test, used for assessing the language dominance of epileptics prior to surgery, are unclear. Alternatively, the results of such a task could be correlated with the results of PET and MRI scans to further investigate hemispheric asymmetry in a quantitative way, thus using converging evidence from both experimental psychological and neurological methods.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:284501 |
| Date | January 1998 |
| Creators | Fine, Philip Arnold |
| Publisher | University of Oxford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://ora.ox.ac.uk/objects/uuid:9a298284-651f-4be9-ae82-2d8862154e47 |
Page generated in 0.0017 seconds