Graham, NL, Zeman, A, Young, AW, Patterson, K and Hodges, JR (1999) Dyspraxia in a patient with corticobasal degeneration: the role of visual and tactile inputs to action. Journal of Neurology, Neurosurgery and Psychiatry. pp. 334-344. ISSN 0022-3050Full text available as:
Objectives-To investigate the roles of visual and tactile information in a dyspraxic patient with corticobasal degeneration (CBD) who showed dramatic facilitation in miming the use of a tool or object when he was given a tool to manipulate; and to study the nature of the praxic and neuropsychological deficits in CBD. Methods-The subject had clinically diagnosed CBD, and exhibited alien limb behaviour and striking ideomotor dyspraxia. General neuropsychological evaluation focused on constructional and visuospatial abilities, calculation, verbal fluency, episodic and semantic memory, plus spelling and writing because impairments in this domain were presenting complaints. Four experiments assessed the roles of visual and tactile information in the facilitation of motor performance by tools. Experiment I evaluated the patient's performance of six limb transitive actions under six conditions: (1) after he described the relevant tool from memory, (2) after he was shown a Line drawing of the tool, (3) after he was shown a real exemplar of the tool, (4) after he watched the experimenter perform the action, (5) while he was holding the tool, and (6) immediately after he had performed the action with the tool but with the tool removed from his grasp. Experiment 2 evaluated the use of the same six tools when the patient had tactile but no visual information (while he was blindfolded). Experiments 3 and 4 assessed performance of actions appropriate to the same six tools when the patient had either neutral or inappropriate tactile feedback-that is, while he was holding a non-tool object or a different tool. Results-Miming of tool use was not facilitated by visual input; moreover, lack of visual information in the blindfolded condition did not reduce performance. The principal positive finding was a dramatic facilitation of the patient's ability to demonstrate object use when he was holding either the appropriate tool or a neutral object. Tools inappropriate to the requested action produced involuntary performance of the stimulus relevant action. Conclusions-Tactile stimulation was paramount in the facilitation of motor performance in tool use by this patient with CBD. This outcome suggests that tactile information should be included in models which hypothesise modality specific inputs to the action production system. Significant impairments in spelling and letter production that have not previously been reported in CBD have also been documented.
|Copyright, Publisher and Additional Information:||© 1999 BMJ Publishing Group|
|Keywords:||ideomotor dyspraxia, corticobasal degeneration, dysgraphia, BASAL GANGLIONIC DEGENERATION, IDEOMOTOR APRAXIA, ALZHEIMERS-DISEASE, QUALITATIVE-ANALYSIS, IDEATIONAL APRAXIA, IMPAIRMENT, PRAXIS, DYSGRAPHIA, DEMENTIA, MOVEMENT|
|Academic Units:||The University of York > Psychology (York)|
|Depositing User:||Repository Assistant|
|Date Deposited:||17 Jul 2006|
|Last Modified:||17 Oct 2013 14:39|