A brief overview of the disorder schizophrenia and the various classification systems used to describe it. However, one cannot ignore the different dimensions and cluster approaches to the classification and diagnosis of schizophrenia when considering the different etiological models of the disorder. 2003) focus on the importance of the prefrontal cortex and the amygdala as essential key components of affect.
Observations regarding the neuropsychological performance of participants will be consolidated in order to speculate broader hypotheses relevant to. As such, Cognitive Neuropsychology methodology was deemed ideal for exploring the current participants. The rationale of this research is to contribute to the understanding of the role of law.
Some of the methodological problems raised in the study of schizophrenia are related to the problem of general poor health, including the long-term effects of neuroleptic drugs (Shallice et al., 1991). The PANSS is a rating measure commonly used to assess the clinical severity of schizophrenia symptoms and to distinguish between positive and negative symptoms (Barnett et al, 2003). Psychometric analysis of the SDMT reveals test-retest reliability of 0.76 (Pearson's coefficient), in addition, the SDMT has been found to be a valid test of general brain defects as well as sensitive to various types of brain damage including lesions laterality (Zog, Papadopoulou, Ricciardelli, Rossor, & Cipolotti, 2004; Smith, 1982).
Additionally, there is an error counter and a reset button on the side of the board (Mansfield, 2002). Therefore, any significant differences found between participants' neuropsychological functioning are assumed to be due to CVA and to be significant in terms of change. This subgroup consists of COWA, which is sensitive to left hemisphere lesions, especially frontal. (Ležak, 2004).
CHAPTER FIVE
As infants and young children, the twins were sociable and cheerful, but were described as living in "a world of their own" and often communicating with each other using terms and words that their families did not understand. The twins attended public school from grade R (seven years old) and completed grades R through 7 with no reported problems. The school progress reports show that the twins' academic performance was virtually identical, consistently achieving high scores.
During this period, the Abbey and Gail families (CVA) allegedly supported the twins and participated in their rehabilitation. Although the twins were increasingly individualized during this period and made separate groups of friends, they remained relatively close. The twins developed an interest in the opposite sex, but did not have suitors, but many male friends.
During this period, the twins' medication was changed to sulpiride (brand name Eglonyt) due to negative side effects. Later, to better stabilize the twins' negative symptoms and reduce side effects, their medication was changed to flupenthixol (or trade name Fluanxol), clozapine (25 mg tablets) and carbamazepine (200 mg), which they are still on. During this time, the twins' positive symptoms were largely stable, and their negative symptoms became more pronounced, with gradually decreasing interest in many of their favorite hobbies, and their symptom profile shifted to residual schizophrenia.
In this section, the research question of the difference in neuropsychological functioning between the participants was addressed (see Chapter 3, research question 4). The Wilcoxon rank sum test was used to examine differences in central tendencies between participants in the overall data set. Once it was determined that there was a statistically significant difference between participants (above), the Sign test was used to determine the direction of the difference (Howell, 2002).
Although participants showed significantly different cognitive functioning in the domains of construction and executive functioning, an examination of specific global and hemispheric functioning was considered useful for questions surrounding the pattern of differences between the twins, providing meaningful data for hemispheric theories (see Chapter 3 , research question 6). In summary, the results presented above showed that the twins' overall pattern of neuropsychological functioning was significantly different (from the Chi-square and Wilcoxon rank sum tests). Furthermore, lateralization functioning appeared to be significantly different between the twins, with a difference in right hemisphere functioning approaching significance.
CHAPTER SIX
This finding related to the second research question appears to support the literature findings of the presence of some degree of cognitive decline in individuals with early schizophrenia. This lack of specificity may have resulted from grouping the visual perception and tactile perception tests together. Chi-square analysis found no statistically significant differences between participants in this subgroup.
The Chi-square analysis showed that there were no statistically significant differences between participants in verbal functions and language skills. The Chi-square analysis showed that there was a statistically significant difference between the participants' executive function and concept formation ability. Chi-square analysis revealed no statistically significant differences between participants' performance on the left hemispheric tests.
Chi-square analysis showed no statistically significant differences between the participants on frontal lobe performance. A statistically significant difference on Chi-square analysis of the participants' lateralizing test scores was found. Third, the neuropsychological and psychological changes are assumed to be related to the CVA in terms of the changes in neurophysiology.
However, it is hoped that these contributions were positive rather than negative and a better possible performance was elicited from the participants due to the previous relationship. Participants and their family reported the feedback given to them (with the participants' consent) as helpful in understanding the participants' various deficits. Furthermore, participants and their family saw the experience as a validating one about managing mental illness both personally and as a family.
Furthermore, research of this nature was a unique opportunity with limited twin studies available in the field of schizophrenia neuropsychology, particularly with a hemispheric focus. Consolidation of the major etiological findings of the literature, as well as current research findings, has clearly brought to the fore the need for additional research in this area. This research highlights the importance of right medial and inferior prefrontal regions in the negative symptoms of schizophrenia, as well as providing information on right hemisphere functioning in individuals with schizophrenia.
Overall, this research has partially answered some of the research questions posed, but has raised many more questions about the role of the right hemisphere and frontal regions in negative symptoms of schizophrenia. Stability of the Wisconsin Card Sorting Test and determination of the reliability of changes in scores.
