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Please use this identifier to cite or link to this item: http://hdl.handle.net/1807/24885

Title: A Model-based Approach to Limb Apraxia: Evidence from Stroke and Corticobasal Syndrome
Authors: Stamenova, Vessela
Advisor: Black, Sandra
Roy, Eric A.
Department: Rehabilitation Science
Keywords: Apraxia
Corticobasal Syndrome
Motor Control
Issue Date: 1-Sep-2010
Abstract: This thesis provides new insights about how the brain controls skilled movements, through the study of limb apraxia in two major neurological disorders: Stroke and Corticobasal Syndrome (CBS). Limb apraxia is a cognitive-motor deficit characterized by impairment in the performance of skilled movement. The Conceptual-Production systems model, used as framework in this thesis, proposes that skilled movement is under the control of three systems: a sensory/perceptual system, a conceptual system and a production system. Deficits in any of these systems produce limb apraxia, and depending on which system is affected, a distinct pattern of apraxia emerges. This information processing approach was used to evaluate performance levels, study brain asymmetries and discern patterns of deficits in each population. In addition, longitudinal assessments in sample subsets revealed patterns of recovery after stroke and of progression in CBS. The first study examined acute-subacute and chronic stroke patients with left (LHD) and right hemisphere damage (RHD) for their ability to pantomime and imitate transitive and intransitive gestures. The results indicated that LHD and acute-subacute were more severely impaired. Concurrent deficits in pantomime and imitation were most common, especially after LHD. Since acute-subacute patients were more severely impaired, in the absence of any therapies, it is likely that some degree of recovery occurs over time. The second study study examined longitudinal recovery in a series of transitive gestures tasks among stroke patients and indicated that patients significantly recovered in all tasks, except in Action Identification, a conceptual apraxia task which probes knowledge of actions. Finally, two comparative studies were conducted in CBS, a neurodegenerative disorder in which apraxia is common, making this one of the first studies that evaluated patient performance on a complete limb apraxia battery. The first study found that patients were often impaired on all gesture production tasks, while conceptual knowledge of gestures and tools was usually preserved. A case series constituted the second study, which documented the progression of apraxia in CBS demonstrating that, while deficits in gesture production usually are present at first examination, deficits in conceptual knowledge are infrequent and in many cases do not develop at all. Study limitations were discussed and it was suggested that future research should expand on our findings for recovery in stroke and progression in CBS.
URI: http://hdl.handle.net/1807/24885
Appears in Collections:Doctoral
Graduate Department of Rehabilitation Science - Doctoral theses

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