Browsing by Author "Mansfield, Douglas John."
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Item Chronic cognitive effects of diving on sport and rescue divers.(2002) Cooke, Gillian.; Mansfield, Douglas John.There has been much debate about whether shallow water diving , in the absence of neurological insult , can lead to cognitive deficits. The aim of this study was to investigate possible neuropsychological effects on two groups of divers , without any known history of decompression illness, who represent opposite ends of the spectrum of diving practice (rescue divers and sport divers) , and to compare them with a non-diving control group. 17 rescue divers , 17 non-diving controls and 15 sport divers were recruited. The groups were matched for age, but not for education. The two diving groups were comparable in terms of diving history. Results of neuropsychological testing indicated that the rescue diving group was not significantly different from the control group, suggesting that rescue diving under controlled conditions is comparatively safe. The sport diver group performed significantly worse than controls on a test of verbal reasoning (Comprehension, SAWAIS-R) and on a measure of word fluency (Controlled Oral Word Initiation Test), suggesting the possibility that risky diving practices may lead to decrements in frontal lobe functioning. Another possibility is that global decrements occur, but that the tests of frontal lobe functioning were more sensitive to mild deficits in functioning. This contention is tentative, and further research into frontal lobe functioning of divers should be conducted. Sport divers are recommended to follow safe diving practices and use dive profiles that avoid bubbling in order to prevent cognitive damage. VIItem Distinguishing between psychogenic and organically-based seizures : the search for critical psychological variables.(2006) Wells, Marlene.; Mansfield, Douglas John.; Collings, Steven John.Differentiating between organic epilepsy and psychogenic pseudoseizures is a difficult task even for experienced practitioners . Both disorders present in a similar manner and at present there are no clinical signs that distinguish between them. Latrogenesis may occur when psychogenic seizures are treated medically and sometimes aggressively in order to control seizure activity. Quality of life is negatively impacted on in both patient groups and stigmatisation and social isolation frequently occur. Psychiatric comorbidity is associated with both epilepsy and psychogenic seizures. The primary aim of this study was to explore the possibility of finding a definitive means of discriminating between the two patient groups. This study assessed quality of life and psychiatric dysfunction in both patient groups using the QOLIE-31 and the SCL-90-R instruments, respectively. The Seizure Questionnaire was used to assess qualitative aspects. The sample (n = 19) was made up of 10 females and nine males with a mean age of 30.6 years (S D = 8.9, range l8 - 44 years). One case of mixed seizures was excluded. The sample was taken from an epilepsy monitoring unit in a hospital in Durban, South Africa. On the scales of the SCL-90-R, Anxiety showed significant difference between groups and on the QOLIE-31 scales, Energy/Fatigue, Cognitive Functioning and Overall score showed significant differences. These differences were in the expected direction as found in previous research i n the literature. These trends need to be interpreted cautiously given the sample size.Item Do cumulative mild head injuries in rugby affect neuropsychological performance? : a comparative study between club rugby players and non-contact sport athletes.(2008) Pentz, Hayley Liza.; Mansfield, Douglas John.Context: Concussion is a major sports medicine concern that is currently under scrutinisation worldwide. Well-publicised cases of careers ending due to multiple concussions, and the potential for permanent, disabling neurocognitive deficits have raised concerns and encouraged further research to take place. Objectives: This study aimed to investigate subjects exposed to mild head injuries with the aim of determining if neuro logical sequelae are detectable. The objectives of this study were to evaluate changes in neuropsychological performance over a period of playing rugby for one full season, which extended over nine months. This study investigated the relationship between concussion history and neuropsychological performance relating to the possible cumulative effects of concussion. Neuropsychological functioning in recently concussed athletes was compared with that of non-injured (control) athletes to detect whether neurological sequelae were present. Investigation into the relationship between post-concussion symptoms and neuropsychological performance was evaluated. The position of play was analysed to see if there were any measurable differences m neuropsychological performance present between forward and backline players. Design, Setting, and Participants: 35 club rugby players and 35 non-contact sports athletes were assessed over a period of 9 months. Both groups underwent pre-season baseline testing and post-season testing. A comprehensive battery of reliable and valid neuropsychological tests was used to assess these subjects, with particular focus on the following 5 areas of cognition: planning, visuo spatial and constructional ability; attention and concentration; memory; verbal fluency and speed of information processing. Results: The data showed that significant differences occurred in rugby players participating regularly in the sport over one full season in terms of changes in neuropsychological test performance in a range of cognitive domains, including planning, visual spatial and constructional ability, attention and concentration, memory and verbal fluency. Numerous significant relationships were found between certain Post Concussion Symptom Scale (PCSS) scores and poor neuropsychological performance, which were considered indicative of subtle effects of sub-concussive injuries and mild head injury (MHI). Surprisingly, following the assessment of concussed players during the season, the data did not show any reliable significant declines in cognitive performance compared to their baseline testing. However, mean scores of the concussed group did show a trend of decreased neuropsychological performance in almost every cognitive domain following the concussive injury. The data did not show any significant relationship between a history of three or more previous concussions and neuropsychological performance. Furthermore, no significant differences in neuropsychological performance between backline and forward players were evident. Conclusion: This research demonstrates that concussion can present serious consequences for athletes and warrants the attention it has received. This present study gives a clear description of the potential negative consequences of playing rugby, which are evident by looking at the change in scores between pre- and post-season testing and poorer performance in most neuropsychological measures following a concussive injury. Although this study dealt mainly with 'normal' players, the results shown here are a cause for concern. What has become evident is that the player need not be exposed to severe concussion in order to experience some form of cognitive impairments. Even if these impairments are minimal, they are however still present and have the potential of accumulating, which could lead to disastrous permanent deficits.Item Personality styles of adolescents previously diagnosed with Attention Deficit Hyperactivity Disorder.(2003) Stephens, Angeline Veronica.; Mansfield, Douglas John.This thesis tests the hypothesis proposed by Liemkuhler (1994) relating to the development of a cluster of personality styles among ADHD adolescents. Liemkuhler suggests that it is a neurobiological dysfunction, through its interaction with psychodynamic and cognitive processes that predisposes the ADHD adolescent to the development of certain personality styles. An absence of appropriate intervention and support increases the risk of these personality styles developing into clinical syndromes. To determine whether differences in personality styles do exist between ADHD adolescents and adolescents without ADHD, the NED Five Factor Inventory (NEDFFI) was group administered to a sample of 25 adolescents who were previously diagnosed as having ADHD (referred to as the ' research group') and 25 controls (referred to as the ' control group') who were matched for age and educational level. Five testable hypotheses were formulated for each of the five personality scales. A comparison of each of the five scales between the research group and the control group yielded no significant result to support Liemkuhler's hypothesis. However, a comparison of the five scales within each group (either the research group or the control group) produced several significant differences. Significant correlations were also found between scales for each group. On the basis of these results it is suggested that specific differences in the facets (traits) that are measured by each of the five personality scales may exist for each group, as opposed to overall group differences in personality styles. It is further proposed that the facets that are tapped may be explained on the basis of assumed differences in the neurobiological and cognitive functioning of both groups. It is tentatively concluded that the results may provide partial support for Liemkuhler's hypothesis. However, it is acknowledged that the complexity of Liemkulher's argument warrants further and more detailed research.Item A preliminary exploration of the construct validity of the Berlin questionnaire as a measure of obstructive sleep apnoea in a South African population : a clinical health psychology perspective.(2006) Baker, Michelle Lydia.; Mansfield, Douglas John.Clinical professionals in South Africa are generally unaware of the impact of obstructive sleep apnoea (OS A). The cost to the state of untreated apnoea may be extremely high. In primary health care encounters OSA often goes undiagnosed. The cascade of symptoms linked to OSA is profound, placing patients at risk for debilitating problems impacting on self and others. The aim of this study was to validate a questionnaire, which could be used at a primary health care level to identify patients with OSA thus cutting costs and improving efficient, effective and ethical service to patients. The Berlin Questionnaire (BQ) (Netzer et al. 1999) was administered to a clinical sample of consenting patients at a private sleep laboratory in Durban, South Africa (N = 119)(completed n = 110). Home-based sleep studies (n = 116) on a portable cardio-respiratory screening device were also obtained for objective comparison. From the results obtained in this South African sample, the BQ showed low validity and reliability (Cronbach a = 0.62 - 0.84) to individual items of the BQ. The total BQ score and high-risk symptom category analysis showed mildly significant correlations with internationally approved protocols. The BQ identified 60% of the high-risk group (AHI >5). Furthermore, risk categories were useful in predicting AHI ratings in 64% of moderate OSA cases and 25% of severe OSA cases. The BQ therefore has useful psychometric properties as an adjunct assessment tool to screen for high-risk OSA cases where resources are scant. Clinical health psychologists are in an ideal position to recognise the risk factors and symptoms of OSA. The clinical assessment and the value of the correct diagnosis will alleviate the treatment of psychological symptoms at a superficial level in primary health care facilities.Item Schizophrenia and hemispheric brain functioning : a neuropsychological case study of a monozygotic twin case.(2006) Rautenbach, Shevonne.; Mansfield, Douglas John.Schizophrenia is a debilitating mental illness which is complex and multifactorial in nature. Currently a full understanding of the exact aetiological and treatment pathways is yet to be understood, with effective treatment of the debilitating and pervasive negative symptoms particularly lacking. However recent advances in neurophysiological and neuropsychological research seem to be converging on theories of the central role of lateralised functional systems. These models implicate right hemispheric hyperactivation in negative symptom patterns, while positive symptoms are thought to be associated with left frontal hypoactivation resulting in compensatory left temporal hyperactivation. Through the use of the Cognitive Neuropsychological case study methodology, this research took an inductive and exploratory approach to a unique case of 41 year old monozygotic twins concordant for schizophrenia and discordant for a right frontal cerebrovascular accident (CVA). From various records the CVA seemingly had a positive effect on the affected-twin's negative symptoms. By means of a selected battery of neuropsychological tests this research focused on patterns of test performance for known functional systems and identified neuropsychological correlates of the CVA and the negative symptom improvement. Statistically significant differences were found between the twins, particularly in the right medial and ventral prefrontal areas. These areas, with their projections to the limbic system and other sub-cortical structures, were highlighted as being important to these differences. From these findings working hypotheses regarding specific lobal structures, relating to existing theories and research in schizophrenia, were posited for future research.Item Subliminal priming and mood : a preliminary study.(1997) Mansfield, Douglas John.; Lachenicht, Lance Gary.The topic ofsubliminalperception (perception without awareness) is investigated in this thesis. A technique of masking by visual noise was developed for use with an IBM-type microcomputer and VGA screen. This technique was used to investigate whether subliminal mood priming influences subjects' resolution oflexical ambiguity in a homophone task designed by Halberstadt et al. (1995). Limited evidence was found for mood-congruent priming, but only for negative emotional priming, and with the most strongly negative items. Some non-specific effects were also found to be associated with negative mood priming. The mood-priming effect was correlated with the negative emotional ratings of these items obtained from a separate group ofsubjects. In a Follow-up study, a self-report mood scale was used to assess subjects' reaction to both negative and positive subliminal stimuli. A pattern oftrends was found which suggested that subjects experienced a paradoxical improvement in mood after exposure to the negative stimulus. No changes were observed in the group exposed to the positive stimuli. A theoretical explanation was entertained which suggested that subjects adaptively attributed their change in affective arousal in terms of experimental demands. of A number ofrelationships to recent research were suggested by these experiments, in particular the finding of a preattentive bias for negative information in subjects with anxiety and non-clinical depression by Bradley et al., (1994, 1995) and Mogg et al.,(1993). It is suggested that measures ofphysiological and cortical arousal should receive attention in future research in order to clarify the response to subliminal stimulation in terms of affective arousal.