Alzheimer’s Disease and Semantic Deficits: A Feature-Listing Study Roberta Perri and Giandaniele Zannino IRCCS Santa Lucia Foundation, Rome, Italy Carlo Caltagirone and Giovanni A. Carlesimo IRCCS Santa Lucia Foundation, Rome, Italy, and Tor Vergata University Objective: The aim of the present study was to investigate the qualitative characteristics of semantic impairment in patients with mild to moderate Alzheimer’s disease (AD). In particular, we wanted to verify if subordinate and distinctive concept features are affected earlier than superordinate or shared ones and whether sensory features are more vulnerable than nonsensory ones. Also, we investigated if feature correlation and level of feature occurrence in concept description (dominance) influence the resilience of concept features to degenerative damage. Methods: We administered a feature-listing task to nine mild and 10 moderate AD patients and 19 matched healthy controls. The concepts utilized were taken from a normative database, which allowed quantifying semantic indexes of the concepts repre- sentation, that is, feature type, distinctiveness, correlation, and dominance. Results: Data confirmed that although semantic knowledge of concepts is overall impoverished in AD patients, (a) superordinate knowledge is better preserved than other types of knowledge, (b) nonsensory information is more preserved than sensory information, and (c) highly shared features are less affected than distinctive ones. Furthermore, patients’ feature production was influenced by dominance and by age of acquisition. Conclusions: These data are in line with theories postulating that among the dimensions along which feature-based semantic representations may vary, those relative to type and distinctiveness are most sensitive to the differential effect of AD. Results also showed a preserved implicit knowledge about how informative a given feature is in these patients and highlighted the importance of early acquisition of concept knowledge for resilience to degenerative damage. Keywords: semantic memory, Alzheimer’s disease, feature listing Advances in the study of human semantic memory in the last decades have been largely based on the observation of the seman- tic memory deficits resulting from a variety of neurological dis- orders (herpes simplex virus encephalitis, cerebro-vascular acci- dents, head injuries, and neurodegenerative diseases). A critical contribution came from the observation of patients with semantic dementia, the neurodegenerative pathology that primarily and se- lectively affects semantic knowledge (Hodges, Patterson, Oxbury, & Funnel, 1992; Snowden, Goulding, & Neary, 1989). In fact, investigation of the nature and consequences of degraded concep- tual knowledge in these patients permitted researchers to document a structured dissolution of semantic memory, which progresses affecting preferentially some kind of information rather than oth- ers. Typically, patients with semantic dementia show more robust memory for general properties of objects than for their more specific attributes (Hodges, Graham, & Patterson, 1995; War- rington, 1975) and for associative/functional than sensory/physical attributes (Lambon Ralph, Graham, Patterson & Hodges, 1999). Observation of such patterns of deficits greatly contributed to shape representational structure of semantic system and to build theories upon the neural maps at the base of the organization of human concepts knowledge (see at this regard McClelland & Rogers, 2003). Significant and broad contributions to the study of semantic system come also from the observation of the progressive decline of semantic memory usually found in patients with Alzheimer’s disease (AD). In fact, these patients progressively lose the ability to name objects and to perform various tasks that tap knowledge about the meaning of words and objects (Salmon, Butters, & Chan, 1999). Although semantic memory impairment does not represent the central symptom of AD, it has been documented that, albeit at milder level, patients with AD show a performance profile on semantic tasks similar to patients with semantic dementia (Rogers, Ivanoiu, Patterson, & Hodges, 2006). Furthermore, similarly to these patients, the progressive course of the AD does not hint semantic knowledge as one but affects it in a progressive fashion. Indeed, analysis of the semantic competence of patients with AD usually shows that some abilities are more preserved than others. So, for example, in a stage of the disease in which patients with AD may be unable to name objects or describe the semantic characteristics of concepts, they may still be able to produce the name of the superordinate category of the objects or place them in the correct semantic category (Hodges, Salmon, & Butters, 1992; Martin, & Fedio, 1983). According to several authors, the semantic deficits in these patients proceed in a hierarchical way, affecting subordinate information (i.e., referring to a specific attribute of a given concept, such as the cow moos) first and only involving superordinate knowledge (the cow is a mammal) later (Hodges, This article was published Online First July 16, 2012. Roberta Perri and Giandaniele Zannino, Laboratory of Clinical and Behavioural Neurology, IRCCS Santa Lucia Foundation, Rome, Italy; Carlo Caltagirone and Giovanni A. Carlesimo, Laboratory of Clinical and Behavioural Neurology, IRCCS Santa Lucia Foundation, Rome, Italy, and Neuroscience Department, Tor Vergata University, Rome, Italy. Correspondence concerning this article should be addressed to Roberta Perri, Fondazione IRCCS Santa Lucia, Via Ardeatina, 306, 00179 Rome, Italy. E-mail: r.perri@hsantalucia.it Neuropsychology © 2012 American Psychological Association 2012, Vol. 26, No. 5, 652– 663 0894-4105/12/$12.00 DOI: 10.1037/a0029302 652