What do Alzheimer’s disease patients know about animals? It depends on task structure and presentation format JILL B. RICH, 1 NORMAN W. PARK, 2 STEPHEN DOPKINS, 3 and JASON BRANDT 4 1 Department of Psychology, York University and Department of Psychology, Baycrest Centre for Geriatric Care, Toronto, Ontario, Canada 2 Kunin-Lunenfeld Applied Research Unit and Department of Psychology, Baycrest Centre for Geriatric Care, Toronto, Ontario, Canada 3 Department of Psychology, George Washington University, Washington, DC 4 Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD (Received May 18, 2000; Revised January 16, 2001; Accepted January 16, 2001) Abstract Deficits on tasks requiring semantic memory in Alzheimer’s disease (AD) may be due to storage loss, a retrieval deficit, or both. To address this question, we administered multiple tasks involving 9 exemplars of the category “animals,” presented as both words and pictures, to 12 AD patients and 12 nondemented individuals. Participants made semantic judgments by class (sorting task), similarity (triadic comparison task), and dimensional attributes (ordering task). Relative to control participants, AD patients were impaired on an unstructured sorting task, but did not differ on a constrained sorting task. On the triadic comparison task, the patients were as likely to make judgments based on size as domesticity attributes, whereas control participants made judgments based primarily on domesticity. The patients’ judgments were also less consistent across tasks than those of control participants. On the ordering tasks, performance was generally comparable between groups with pictures but not words, suggesting that pictures enable AD patients to access information from semantic memory that is less accessible with lexical stimuli. These results suggest that AD patients’ semantic judgments are impaired when the retrieval context is unstructured, but perform normally under supportive retrieval conditions. (JINS, 2002, 8, 83–94.) Keywords: Alzheimer’s disease, Semantic memory, Format effects INTRODUCTION Although episodic memory impairment is the earliest and most pervasive deficit in Alzheimer’s disease (AD), lan- guage abilities are frequently impaired as well. Studies of verbal memory are inextricably tied to language function; indeed, the relation between memory and language is ex- plicitly recognized in the concept of semantic memory, as originally formulated by Tulving (1972). Semantic memory refers to a system for storing, organizing, and manipulating information pertaining to the meaning of words, concepts, and their associations, as well as to more general world knowledge. This organized knowledge system, often con- ceptualized as a broadly distributed network, enables peo- ple to make judgments about the properties and functions of items, such as whether a hammer is a living or nonliving thing, can be categorized as a tool, has a handle, or is larger than a screwdriver. The two best-documented language deficits in AD occur on tasks requiring semantic memory, namely confrontation naming and verbal fluency (e.g., Bayles & Kaszniak, 1987; Bayles & Tomoeda, 1983; Huff et al., 1986; Martin & Fe- dio, 1983; Salmon et al., 1999). However, there is some dispute regarding the source of the impairment on these tasks. A number of investigators attribute these deficits to degraded conceptual knowledge associated with damage to brain areas critical to semantic memory (e.g., Chertkow & Bub, 1990; Hodges et al., 1992; Martin, 1992). Others ar- gue that the impaired performance reflects a loss of lexical access to preserved concepts, possibly due to inefficient search strategies (e.g., Nebes, 1989, 1992; Ober & Shenaut, 1995). These theoretical positions may be characterized as Reprint requests to: Jill B. Rich, Ph.D., Department of Psychology, York University, 4700 Keele Street,Toronto, Ontario, M3J 1P3, Canada. E-mail: jbr@yorku.ca Journal of the International Neuropsychological Society (2002), 8, 83–94. Copyright © 2002 INS. Published by Cambridge University Press. Printed in the USA. DOI: 10.1017.S1355617701020082 83