Executive dysfunction and weak central coherence : neither theory suitably explains a core cognitive deficit in autism spectrum disorders
| Autor: | Daniels, Michelle |
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| Jazyk: | angličtina |
| Rok vydání: | 2008 |
| Předmět: | |
| Druh dokumentu: | Master's Thesis |
| Popis: | Includes bibliographical references (leaves 112-124). Theories of weak central coherence (WCC; a local detail-specific way of processing information that allows individuals to focus on and remember minutiae) and executive dysfunction (EF dysfunction; an inability to employ goal-directed cognition to plan, organize, and alternate between tasks, or to inhibit incorrect responses) largely dominate current understandings of the neurocognitive profile in autism spectrum disorders (ASD). Recent empirical evidence suggests, however, that neither theory adequately explains the uneven profile of autistic cognition (e.g., attention deficits and relative spatial strengths), and that neither is satisfactorily applicable to autistic individuals across the spectrum. Moreover, recent research provides results contradictory to those predicted by these theoretical frameworks. Consequently, the theories' validity as explanations of a core cognitive deficit in ASD has come into question. The current research attempts to resolve some of the questions raised by the shortcomings of these two theoretical frameworks. In addition, this research aims to investigate the nature of spatial cognition as an assumed strength following from reports of enhanced visiospatial skill in ASD. Twenty-five high-functioning autistic (HFA; IQ> 70), 16 low-functioning autistic (LFA; IQ::: 70), 13 Asperger's syndrome (AS), 13 mentally retarded (MR), and 22 typically developing (TD) children matched according to sex and handedness were assessed on a comprehensive battery of clinical and experimental neurocognitive measures. There were no group differences on the EF domain, attentional control. On the domains of cognitive flexibility and goal setting, participants in both the AS and LF A groups did not display the EF deficit predicted by the EF dysfunction theory when compared to IQ-matched controls. Results: The only support shown for EF dysfunction was with HF A children. These participants made significantly more perseverative errors on the Wisconsin Card Sort Test64 (WCST64 ) as an outcome variable of cognitive flexibility and performed more poorly on the Tower of London (ToL) total correct (cognitive flexibility) and total time (goal-setting) scores than controls, without the influence of IQ. In terms of WCC, AS and LF A participants performed no better than IQ-matched controls on visuo-spatial tasks- the Block Design (BD), Rey-Osterrieth Complex Figure Test (ROCF), and Children's Embedded Figures Test (CEFT). Broader spatial cognition was similarly intact but not superior in AS and LF A participants. On those spatial measures not influenced heavily by intelligence, the HF A group were shown to have a diminished capacity for allocentric spatial cognition compared to controls. The results of this investigation provided only partial support for the theory of EF dysfunction and no support for the theory of WCC. Instead, they suggest that neither theory is suitable as an explanation of a core cognitive deficit in ASD. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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