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Grasping tools: effects of task and apraxia.
Jennifer Randerath1, Yong Li, Georg Goldenberg
1Clinic of Neuropsychology, Munich-Bogenhausen Hospital, Dachauerstr. 164, 80992 Munich, Germany. Jennifer.Randerath@extern.lrz-muenchen.de
Neuropsychologia
|November 4, 2008
Summary
Apraxia disrupts tool use by impairing knowledge access and movement planning. Grasping a tool is task-specific, with functional grasps crucial for tool use, and apraxic patients struggle to integrate this knowledge.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Motor Control
Background:
- Apraxia frequently impairs tool-use knowledge access and movement planning.
- Understanding how apraxia affects grasping and tool use is crucial for rehabilitation.
Purpose of the Study:
- Investigate differences between 'transport' and 'use' tasks in tool grasping.
- Examine the influence of apraxia on grasping movements when tools are presented in a specific orientation.
Main Methods:
- Tested 20 controls, 10 right brain damage (RBD) patients, and 17 left brain damage (LBD) patients (10 moderately to severely apraxic).
- Participants performed 'transport' and 'use' tasks with tools, grasping them to either use or move them into a container.
- Distinguished between functional and non-functional grasps.
Main Results:
- Task content significantly influences object grasping.
- Nearly all participants used functional grasps during the 'use'-task; inappropriate non-functional grasps preceded apraxic tool-use behavior.
- Functional grasping was significantly reduced in all groups during the 'transport'-task compared to the 'use'-task.
Conclusions:
- Grasping a tool is task-specific, influenced by object knowledge, structural features, biomechanics, and experience.
- Effective tool use requires integrating perception, structural understanding, and functional knowledge.
- Apraxic patients may fail to access necessary information for tool use and grasping.
