Background: Executive impairment is common in Parkinson’s disease (PD). However, it is unknown which dimensions of executive function are assessed by commonly used neuropsychological instruments and if clinical correlates of specific dimensions exist. Method: A convenience sample of 46 PD patients was evaluated with three executive function tests: the Tower of London-Drexel, the Trail-Making Test and the Stroop Color-Word Test. Factor analysis was used to probe for dimensions of executive control, and linear regression models were used to explore the association between the generated factors and other clinical features. Results: Factor analysis revealed two executive factors, one related to planning (eigenvalue = 4.2) and the other to inhibitory control (eigenvalue = 1.8), together accounting for 75% of the variance in scores. In linear regression models, poorer planning was associated with increasing severity of apathy (t = 2.11, p = 0.041), and diminished inhibitory control was associated with increasing severity of parkinsonism (t = 2.78, p = 0.008) and lower educational level (t = –2.23, p = 0.032). Conclusions: Planning deficits and diminished inhibitory control are two dimensions of executive impairment in PD, the former associated with decreased motivation and the latter with increased motor slowing. Similar performance on both executive and non-executive components of these instruments suggests that results of executive testing in PD may be confounded by non-executive deficits.

Keywords:
Parkinson disease, executive impairment, Planning function, Inhibitory control
This content is only available via PDF.
© 2005 S. Karger AG, Basel
2005
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.