Apraxia during Wada testing
- A. L. Foundas, MD,
- R. Henchey, MD,
- R. L. Gilmore, MD,
- E. B. Fennell, PhD and
- K. M. Heilman, MD
- From the Department of Psychiatry and Neurology (Dr. Foundas), Tulane University School of Medicine, and the Neurology Service (Dr. Foundas), Veterans Affairs Medical Center, New Orleans, LA; the Center for Neuropsychological Studies (Drs. Henchey, Gilmore, Fennell, and Heilman) and the Departments of Neurology (Drs. Henchey, Gilmore, and Heilman) and Clinical and Health Psychology (Dr. Fennell), University of Florida College of Medicine, and the Neurology Service (Dr. Heilman), Veterans Affairs Medical Center, Gainesville, FL.
- Address correspondence and reprint requests to Dr. Anne L. Foundas, Department of Psychiatry and Neurology, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112-2632.
Abstract
Apraxia is the loss of the ability to perform learned skilled movements correctly. In right-handers, apraxia and aphasia are most frequently associated with left-hemisphere lesions. When they are dissociated, however, aphasia is more common in the absence of apraxia than vice versa. There are two hypotheses that can account for this discrepancy: (1) in right-handers, praxis is more likely than language to be mediated by the right hemisphere, or (2) the left-hemisphere network that mediates language is either more widely distributed than the network that mediates praxis or is more likely to be in the middle cerebral artery distribution. We studied apraxia in a group of right-handers undergoing selective hemispheric anesthesia, or Wada testing. All nine subjects had language lateralized to the left hemisphere, and seven of the nine had praxis lateralized to the left hemisphere. Two of the subjects had praxis bilaterally represented. Although our data suggest that speech and praxis functions tend to be lateralized to the left hemisphere in most right-handers, praxis appears to be more distributed between the hemispheres than speech-language functions. Furthermore, an analysis of the types of errors made during praxis testing suggests differential roles of the hemispheres in praxis functions.
- Copyright 1995 by the American Academy of Neurology
