Category-specific naming deficit following cerebral infarction.
ABSTRACT Studies aimed at characterizing the operation of cognitive functions in normal individuals have examined data from patients with focal cerebral insult. These studies assume that brain damage impairs functions of the cognitive processes along lines that honour the 'normal' pre-morbid organization of the cognitive system. For example, detailed study of individual brain-damaged patients has revealed apparently selective disruption of cognitive functions such as auditory/verbal working memory, phonological processing ability, grapheme-to-phoneme translation procedures and semantic processing. Warrington et al. have studied patients with even more fine-grained selective disturbances of the semantic system. The most selective deficits have been reported for four patients who were significantly better at identifying inanimate objects than they were at identifying living things and foods. These patterns of selective deficit after localized brain damage provide important information about the normal organization of the lexicon, and ultimately about how components of the lexical system are related to particular neural substrates. Here, we report a case study of a patient demonstrating a very selective disturbance of the ability to name items from two related semantic categories. Despite normal performance on a large battery of lexical/semantic tasks, the patient shows a consistent and striking disability in naming members of the semantic categories of 'fruits' and 'vegetables'. The selectivity of this deficit supports a category-specific organization of the mental lexicon, and suggests independence of the processing routes involving naming and name recognition.
Chapter: The Conceptual Structure Account: A cognitive model of semantic memory and its neural instantiation04/2007: pages 265-301; , ISBN: 0521848709
Article: Alterations of the sense of "humanness" in right hemisphere predominant frontotemporal dementia patients.[show abstract] [hide abstract]
ABSTRACT: To evaluate the sense of "humanness" in frontotemporal dementia (FTD) patients with right hemispheric involvement. Early in the course, FTD is often asymmetric, and those with predominant right frontotemporal disease have disproportionate disturbances in social behavior and empathy. A disruption in a sense of humanness may underlie these behavioral disturbances. Sixteen patients with asymmetric FTD on functional neuroimaging underwent recognition tests of facial masking, human-animal morphing, and facial distortion. Additional tests evaluated facial discrimination and the recognition of famous faces, facial emotions, and animate-inanimate differences. On the distorted and morphed face tasks, 8 FTD patients with predominant right hemisphere involvement were significantly more likely to call morphed and distorted faces "human" as compared with both 8 FTD patients with predominant left hemisphere involvement and normal controls. The FTD groups did not differ on thresholds for recognizing masked faces or on other face recognition measures. In FTD, right hemispheric involvement may alter the threshold for judging someone as human independent of the recognition of faces or facial affect. These results suggest that a specific sense of humanness facilitates a person recognition network in the right frontotemporal region of the brain.Cognitive and Behavioral Neurology 09/2004; 17(3):133-8. · 1.34 Impact Factor