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Ideomotor apraxia: behavioral dimensions and neuroanatomical basis
A Schnider1, R E Hanlon, D N Alexander
1Department of Neurology, University of California at Los Angeles School of Medicine, USA.
Brain and Language
|June 1, 1997
Summary
Left-hemisphere damage impairs complex, commanded movements, revealing motor dominance. This dominance stems from artificiality and complexity, not movement meaningfulness, in ideomotor apraxia.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Neurology
Background:
- Ideomotor apraxia, characterized by disordered movement execution to command, often results from left-hemisphere damage.
- This suggests the left hemisphere plays a dominant role in specific types of motor control.
Purpose of the Study:
- To investigate the factors contributing to left-hemisphere motor dominance in movement execution.
- To differentiate the influence of movement meaningfulness versus command modality and complexity.
Main Methods:
- Evaluated 27 patients with unilateral hemispheric stroke and 10 controls.
- Assessed performance on meaningful movements to command and imitation of nonsense movements across different command modalities.
Main Results:
- Patients with left-hemisphere damage showed poorer performance on both meaningful and nonsense movements compared to other groups.
- Movement meaningfulness was irrelevant to left-hemisphere motor dominance; performance varied with command modality and movement complexity.
- No correlation was found between lesion location within the left hemisphere and ideomotor apraxia severity.
Conclusions:
- Left-hemisphere motor dominance is linked to the artificiality of performing movements to command, outside natural contexts.
- Increased spatial and temporal complexity of demanded movements significantly influences this dominance.
- The findings clarify the neural underpinnings of apraxia and hemispheric specialization for motor control.