Melbourne School of Psychological Sciences - Theses
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ItemEarly neuropsychological change in possible dementia of the Alzheimer type( 1996)Early detection of dementia of the Alzheimer type (DAT) is vital in understanding the natural course of the disease, which in turn guides the development of potential pharmacological treatment and management strategies. However, early detection of DAT has traditionally proved difficult. The study described in this thesis comprehensively examined neuropsychological function over a 24 month period in patients with early dementia, using as comparison groups individuals with isolated memory complaints (questionable dementia, QD), and normal controls. The neuropsychological battery utilised included standard measures of cognition, such as the WAIS-R and WMS-R, and experimentally-derived computerised tests of memory. The same pattern of neuropsychological change was exhibited by patients with early DAT and by QD subjects who later fulfilled standard criteria for the disease. In both groups pronounced impairment of recent memory preceded deficits in language and visuospatial function. The progression of cognitive deterioration observed in DAT is likely to reflect the spread of neuropathology throughout the cortex. In view of these findings, the selection of appropriate neuropsychological measures for the detection and staging of early DAT is discussed. One computerised measure, the paired associate learning test, was found to be particularly efficacious in the prediction and early detection of DAT. The QD group performed at a similar level to normal controls when first assessed using the paired associate learning subtest. However, over the course of the study, 43% of the QD subjects exhibited significant deterioration in scores on this measure. All subjects who deteriorated on the computerised paired associate learning task met standard criteria for DAT at the conclusion of the study. Diagnosis of probable DAT was not predicted by any other demographic or psychometric variable. These findings are discussed in terms of the special sensitivity of the associate learning paradigm to the neuropathology of Alzheimer's disease.
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ItemNeuropsychological recovery after concussion in Australian rules footballers( 1995)The past 20 years have witnessed a significant growth in research into the neuropsychological sequelae of mild head injury acquired in the course of motor vehicle accidents. Little systematic investigation, however, has been devoted to the neuropsychological consequences of head injury acquired on the sports field. The dearth of research in this area has been detrimental to the formation of adequate policy for the management of injured players. This thesis consists of four studies examining the acute and subacute effects of concussion on cognitive function in Australian rules footballers. Current assessment of post-traumatic amnesia on the field of play is informal, varying from situation to situation, and of unknown sensitivity. The first study considered the sensitivity of orientation and recent memory items in the acute assessment of concussion. Items relating to memory for recent events were found to be more sensitive than orientation items. These findings have important implications for the diagnosis of concussion in sport, particularly in cases where loss of consciousness does not occur or is not observed. Studies two and three examined neuropsychological function in the immediate recovery phase after the resolution of post-traumatic amnesia. While performance on tests of attention and speed of information processing was found to be reduced during the first days after injury, performance returned to normal levels over the first 18 days post-injury. The forth study examined the impact of concussion on sporting competence. There have been concerns that ongoing neurobehavioural effects of concussion might reduce a player’s level of function in competition thereby increasing the risk of suffering further injury. This risk is further compounded by the high attentional demands of the sport. The results showed that players were able to perform at pre-injury levels within 2 to 3 weeks of injury, and that the risk of repeated concussion appeared to be a function of game exposure. Concussed players made a good recovery in terms of neuropsychological measures employed and functional indices of playing performance, reinforcing the view that concussive injury can be associated with reversible neuropsychological consequences. This work contributes to a greater understanding of the neurocognitive sequelae of concussive injury involving low levels of brain commotion and post-injury assessment and recovery of athletes. Further, the present findings have important practical and financial implications for the rehabilitation and management of individuals suffering such injury.