The influence of gender and lesion location on naming disorders for animals, plants and artefacts.

The aim of this systematic review of single case studies of patients showing a category-specific disorder was to evaluate the influence of gender and lesion location on category-specific disorders for biological versus artefact categories and, within the former, for animals versus plant life categories. Two complementary studies were made, taking into account all the available single case reports of category-specific disorders found in the literature. The first study consisted of an overall statistical evaluation of the influence that gender and lesion location can have upon naming scores obtained with these different categories in patients selected only because they showed some kind of category-specific disorder. The second study assessed the influence of these variables on more selected groups of patients, contrasting those showing a categorical impairment for living things versus artefacts and, respectively, for animals versus plant life categories. Results of these studies consistently showed that: (a) Lesion location has a strong influence on the distinction between biological and artefacts categories, but not on that between animals and plant life domains. In patients with a prevalent impairment either for animals or for plant life items, lesions usually encroach upon the anterior or the posterior parts of the ventral stream of visual processing, whereas in patients with a prevalent impairment for artefacts they are located elsewhere (usually on more dorsal structures of the brain). (b) Gender, on the contrary, does not influence the distinction between living and non-living things, but, within the living entities, has a strong influence on the distinction between animals and plant life. Consistent with data obtained in normal people, which show that men are more familiar with animals and women with fruit and vegetables, men were, indeed, more impaired with plant life categories, whereas women were more impaired with animals.