Selectivity of executive function deficits in mild cognitive impairment.

Abstract

Impairment in executive cognition (EC) is now recognized as relatively common among older persons with mild cognitive impairment (MCI), and may be predictive of the development of dementia. However, both MCI and executive functioning are broad and heterogeneous constructs. The present study sought to determine whether impairments in specific domains of EC are associated with specific subtypes of MCI. 124 MCI patients were divided into four subgroups (amnestic versus nonamnestic, and single-versus multiple-domain) based on their performance of widely-used neuropsychological screening tests. These patients and 68 normal elderly were administered 18 clinical and experimental tests of executive function. Principal components analysis suggested two highly reliable EC components, planning/problem-solving and working memory, and a less reliable third component, judgment. Planning/problem-solving and working memory, but not judgment, were impaired among the MCI patients. This was true even among those with Apure amnestic@ MCI, the least impaired group overall. Multiple-domain MCI patients had more severe impairments in planning/problem-solving and working memory than single-domain patients, leading to the supposition that they, not pure amnestic MCIs, are at highest risk of imminent dementia. Keywords executive function; mild cognitive impairment; dementia; principal components analysis; flexibility; working memory; planningThe status of mild cognitive impairment (MCI) as an important clinical entity remains debated. Expert opinion ranges from it being early Alzheimer=s disease (AD) in virtually all cases (Morris et al., 2001) to it being a diagnostic nonentity (Milwain, 2000;Gauthier & Touchon, 2005; Whitehouse, 2007). Most opinions fall somewhere between these two extremes, and view MCI as a heterogeneous cognitive state that sometimes heralds the onset of progressive Address correspondence to: Jason Brandt, Ph.D., Department of Psychiatry and Behavioral Sciences, The Johns Hopkins Hospital, 600 N. Wolfe Street, Meyer 218, Baltimore, MD 21287-7218, phone 410-825-9048, fax 410-955-0504, jbrandt@jhmi.edu. Publisher's Disclaimer: The following manuscript is the final accepted manuscript. It has not been subjected to the final copyediting, fact-checking, and proofreading required for formal publication. It is not the definitive, publisher-authenticated version. The American Psychological Association and its Council of Editors disclaim any responsibility or liabilities for errors or omissions of this manuscript version, any version derived from this manuscript by NIH, or other third parties. The published version is available at www.apa.org/journals/neu. NIH Public Access Author ManuscriptNeuropsychology. Author manuscript; available in PMC 2010 September 1. Published in final edited form as:Neuropsychology. Chertkow et al., 2007). Much recent research has focused on determining the characteristics of patients with MCI that predict the progression to AD or another dementia.It is now widely recognized that several ...

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