The Importance of Measuring Executive Function When Studying the Effects of Cognition-Enhancing Agents
Authors: Kenneth Rockwood
Journal: Annals of Internal Medicine (2008)

Letters2 September 2008The Importance of Measuring Executive Function When Studying the Effects of Cognition-Enhancing AgentsKenneth Rockwood, MDKenneth Rockwood, MDFrom Dalhousie University, Halifax, Nova Scotia B3H 2E1, Canada.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-149-5-200809020-00016 SectionsAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail TO THE EDITOR:In their comprehensive systematic review, Raina and colleagues (1) noncontroversially conclude that the effect sizes for cholinesterase inhibition in Alzheimer disease typically are small and that translation of these effects into patients' quality of life remains problematic. Perhaps even more can be concluded from the literature. If we accept that the average small effect size represents a distribution of effects, it is reasonable to ask why some people seem to do well in response to treatment and others do not. There are 3 possible answers.First, a dose response can be demonstrated at the group level, such ...References1. Raina P, Santaguida P, Ismaila A, Patterson C, Cowan D, Levine M, et al. Effectiveness of cholinesterase inhibitors and memantine for treating dementia: evidence review for a clinical practice guideline. Ann Intern Med. 2008;148:379-97. [PMID: 18316756] LinkGoogle Scholar2. Rockwood K. Size of the treatment effect on cognition of cholinesterase inhibition in Alzheimer's disease. J Neurol Neurosurg Psychiatry. 2004;75:677-85. [PMID: 15090558] CrossrefMedlineGoogle Scholar3. Rockwood K, MacKnight C. Assessing the clinical importance of statistically significant improvement in anti-dementia drug trials. Neuroepidemiology. 2001;20:51-6. [PMID: 11359070] CrossrefMedlineGoogle Scholar4. Royall DR, Lauterbach EC, Cummings JL, Reeve A, Rummans TA, Kaufer DI, et al. Executive control function: a review of its promise and challenges for clinical research. A report from the Committee on Research of the American Neuropsychiatric Association. J Neuropsychiatry Clin Neurosci. 2002;14:377-405. [PMID: 12426407] CrossrefMedlineGoogle Scholar5. Voss SE, Bullock RA. Executive function: the core feature of dementia? Dement Geriatr Cogn Disord. 2004;18:207-16. [PMID: 15211077] CrossrefMedlineGoogle Scholar6. Rockwood K, Fay S, Gorman M, Carver D, Graham JE. The clinical meaningfulness of ADAS-Cog changes in Alzheimer's disease patients treated with donepezil in an open-label trial. BMC Neurol. 2007;7:26. [PMID: 17760991] CrossrefMedlineGoogle Scholar7. Rockwood K. Quality of life outcomes.. In: Rockwood K, Gauthier S, eds. Trial Designs and Outcomes in Dementia Therapeutic Research. London: Taylor & Francis; 2006:131-40. Google Scholar8. Qaseem A, Snow V, Cross JT, Forciea MA, Hopkins R, Shekelle P, et al; American College of Physicians/American Academy of Family Physicians Panel on Dementia. Current pharmacologic treatment of dementia: a clinical practice guideline from the American College of Physicians and the American Academy of Family Physicians. Ann Intern Med. 2008;148:370-8. [PMID: 18316755] LinkGoogle Scholar9. Rockwood K, Fay S, Song X, MacKnight C, Gorman M; Video-Imaging Synthesis of Treating Alzheimer's Disease (VISTA) Investigators. Attainment of treatment goals by people with Alzheimer's disease receiving galantamine: a randomized controlled trial. CMAJ. 2006;174:1099-105. [PMID: 16554498] CrossrefMedlineGoogle Scholar10. Rockwood K, Fay S, Jarrett P, Asp E. Effect of galantamine on verbal repetition in AD: a secondary analysis of the VISTA trial. Neurology. 2007;68:1116-21. [PMID: 17404193] CrossrefMedlineGoogle Scholar Author, Article, and Disclosure InformationAuthors: Kenneth Rockwood, MDAffiliations: From Dalhousie University, Halifax, Nova Scotia B3H 2E1, Canada.Disclosures: Dr. Rockwood has worked with each of the drug companies that make cholinesterase inhibitors. The VISTA (Video-Imaging Synthesis of Treating Alzheimer's Disease) trial (9, 10) was an investigator-initiated, peer-reviewed, double-blind clinical trial, funded in part by the Canadian Institutes of Health Research and Janssen-Ortho Canada. He is also the founder and majority shareholder of DementiaGuide, a Web-based company that provides information on dementia and its treatment. DementiaGuide has a contract with Pfizer Canada to improve patient-centered measurement in a clinical trial. PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetailsSee AlsoEffectiveness of Cholinesterase Inhibitors and Memantine for Treating Dementia: Evidence Review for a Clinical Practice Guideline Parminder Raina , Pasqualina Santaguida , Afisi Ismaila , Christopher Patterson , David Cowan , Mitchell Levine , Lynda Booker , and Mark Oremus The Importance of Measuring Executive Function When Studying the Effects of Cognition-Enhancing Agents Parminder Raina , Pasqualina L. Santaguida , and Christopher Patterson Metrics Cited byFor How Long Should We Use Symptomatic Therapies to Treat People with Alzheimer Disease? 2 September 2008Volume 149, Issue 5Page: 358-359KeywordsAlzheimer diseaseCaregiversCholinesterase inhibitorsClinical trialsConflicts of interestDementiaDrugsQuality of lifeSystematic reviews ePublished: 2 September 2008 Issue Published: 2 September 2008 Copyright & PermissionsCopyright © 2008 by American College of Physicians. 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