This Article Full Text Full Text (PDF) All Versions of this Article: 39/3/806    most recent STROKEAHA.107.489997v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Libon, D. J. Articles by Pennisi, A. Search for Related Content PubMed PubMed Citation Articles by Libon, D. J. Articles by Pennisi, A. Related Collections CT and MRI Other diagnostic testing Behavioral Changes and Stroke

(Stroke. 2008;39:806.)
© 2008 American Heart Association, Inc.

Original Contributions

Linking MRI Hyperintensities With Patterns of Neuropsychological Impairment

Evidence for a Threshold Effect

David J. Libon, PhD; Catherine C. Price, PhD; Tania Giovannetti, PhD; Rodney Swenson, PhD; Brianne Magouirk Bettcher, BA; Kenneth M. Heilman, MD Alfio Pennisi, MD

From the Department of Neurology (D.J.L.), Drexel University College of Medicine, Philadelphia, Pa; the Departments of Clinical and Health Psychology & Anesthesiology (C.C.P.), University of Florida, Gainesville, Fla; the Department of Psychology (T.G., B.M.B.), Temple University, Philadelphia, Pa; the Department of Neuroscience (R.S.), University of North Dakota Medical School, Fargo, ND; the Department of Neurology (K.M.H.), University of Florida, and Veteran Affairs Medical Center, Gainesville, Fla; and South Jersey Radiology Associates (A.P.), Voorhees, NJ.

Correspondence to David J. Libon, PhD, Department of Neurology, Drexel University College of Medicine, Mail Stop 423, 245 North 15th St, Philadelphia, PA, USA, 19102. E-mail dlibon{at}drexelmed.edu

Background and Purpose— Leukoaraiosis (LA) might interrupt intra- and interhemispheric communication and thus induce cognitive impairments and dementia. It remains unclear, however, if there is a volume threshold of LA that is needed before either the signs of dementia and/or a specific pattern of neuropsychological impairment become manifest. Roman et al has suggested that 25% of white matter may need to be involved before white matter alterations influence the clinical signs associated with dementia. The purpose of this study is to ascertain the threshold of MRI-LA as measured with a visual rating scale needed to induce specific patterns of neuropsychological impairment associated with dementia.

Methods— One hundred fifteen patients with dementia received a comprehensive neuropsychological examination and the severity of MRI-LA was measured using a 40-point LA scale.

Results— Patients were categorized into low (mean LA=4.21±2.92; 3.22%–17.82%), moderate (mean LA=12.58±2.54; 25.01%–37.80%), and severe (mean LA=22.36±4.04; 45.80%–66.00%) LA groups. Patients in the mild LA group obtained markedly lower scores on tests of episodic memory compared with working memory, a neuropsychological profile often associated with Alzheimer disease. Patients with moderate LA displayed equal impairment on neuropsychological tests. Patients in the severe LA group obtained significantly lower scores on tests of working memory as compared with episodic memory.

Conclusions— These data provide evidence that a threshold of moderate MRI-LA as measured with a visual rating scale is associated with greater and/or equal impairment on tests of working memory versus episodic memory and provides a benchmark to assess the effect of MRI-LA on the clinical presentation of dementia.

Key Words: Alzheimer disease • Binswanger disease • episodic memory • executive functions • leukoaraiosis • subcortical dementia • vascular dementia