Callosal ideomotor apraxia in Alzheimer’s disease

ABSTRACT

Background/objective: Impaired ability to perform skilled movements with the left upper limb in patients with corpus callosum injury has been well described (callosal apraxia) with some displaying spatial–temporal errors primarily in response to verbal commands (verbal callosal disconnection apraxia), with imitation, and when using actual tools (callosal ideomotor apraxia). Additionally some patients with callosal injury also make content errors when selecting and using the incorrect tool with their left upper limb (callosal conceptual apraxia). Interestingly, patients with Alzheimer’s disease (AD) reveal anatomic evidence of callosal degeneration but callosal apraxia in AD has not been described. The purpose of this study was to learn whether patients with AD display forms of callosal apraxia. Method: Participants were 22 right-handed patients with AD and 24 matched controls. Both upper limbs were tested by having subjects pantomime transitive movements to command and imitation. Participants also viewed pictures of an incomplete task and attempted to pantomime the action needed to complete the task. Results and conclusions: When compared to controls, the participants with AD demonstrated ideomotor and conceptual apraxias of both upper limbs; however, ideomotor apraxia of their left hand was more robust than that of their right hand, suggesting a hemispheric disconnection.

KEYWORDS:

• Alzheimer’s disease
• Corpus callosum
• Apraxia
• Disconnection

Acknowledgements

This study was completed in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the University of Florida. Thanks are extended to the faculty and staff of the University of Florida Memory Disorder Clinic for allowing us to recruit participants for this study from their clinical population. The authors also want to acknowledge assistance provided by Cristina Posse and Lauren Meffen, who helped test participants.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Supported in part by the State of Florida Memory Disorder Clinics and the Research Service of the Department of Veterans Affairs, Gainesville Florida. This study was funded by (a) the VA Office of Academic Affiliations and Patient Care Services Predoctoral Fellowship in Speech Pathology; (b) the VA Rehabilitation Research and Development Office Centers of Excellence Brain Rehabilitation Research Center; (c) the National Institute of Deafness and Communication Disorders, National Institutes of Health; (d) the Florida Department of Elder Affairs, Memory Disorder Clinic; and (e) the University of Florida, Department of Communication Sciences and Disorders and Department of Neurology.