An Attenuation of the "Normal" Category Effect in Patients with Alzheimer's Disease: A Review and Bootstrap Analysis

Autor/inn/en	Moreno-Martinez, F. Javier; Laws, Kieth R.
Titel	An Attenuation of the "Normal" Category Effect in Patients with Alzheimer's Disease: A Review and Bootstrap Analysis
Quelle	In: Brain and Cognition, 63 (2007) 2, S.167-173 (7 Seiten) PDF als Volltext Verfügbarkeit
Sprache	englisch
Dokumenttyp	gedruckt; online; Zeitschriftenaufsatz
ISSN	0278-2626
DOI	10.1016/j.bandc.2006.11.003
Schlagwörter	Semantics; Patients; Familiarity; Alzheimers Disease; Language Impairments; Research Methodology; Control Groups; Older Adults; Language Processing + Suchen Sie Ihr Suchwort? Semantik; Patient; Speech disorder; Speech disorders; Speech disabilities; Speech disability; Speech handicap; Speech handicaps; Speech impairment; Speech impairments; Language handicaps; Sprachbehinderung; Research method; Forschungsmethode; Älterer Erwachsener; Sprachverarbeitung
Abstract	There is a consensus that Alzheimer's disease (AD) impairs semantic information, with one of the first markers being anomia i.e. an impaired ability to name items. Doubts remain, however, about whether this naming impairment differentially affects items from the living and nonliving knowledge domains. Most studies have reported an impairment for naming living things (e.g. animals or plants), a minority have found an impairment for nonliving things (e.g. tools or vehicles), and some have found no category-specific effect. A survey of the literature reveals that this lack of agreement may reflect a failure to control for intrinsic variables (such as familiarity) and the problems associated with ceiling effects in the control data. Investigating picture naming in 32 AD patients and 34 elderly controls, we used bootstrap techniques to deal with the abnormal distributions in both groups. Our analyses revealed the previously reported impairment for naming living things in AD patients and that this persisted even when intrinsic variables were covaried; however, covarying control performance eliminated the significant category effect. Indeed, the within-group comparison of living and nonliving naming revealed a larger effect size for controls than patients. We conclude that the category effect in Alzheimer's disease is no larger than is expected in the healthy brain and may even represent a small diminution of the "normal" profile. (Author).
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Erfasst von	ERIC (Education Resources Information Center), Washington, DC
Update	2017/4/10