ABSTRACT
Since the publication of Warrington and Shallice’s (1984) seminal paper on the topic, more than 100 patients with category-specific semantic impair ment have been described in the literature, predominantly in
the form of single-case studies. The term “category specificity” is actually something of a misnomer, as no patient has been reported with an entirely selective impairment for one domain of knowledge. We will, however, continue to use this term as it is so solidly established in the literature. The majority of these cases have relatively spared performance for nonliving or man-made objects but significantly poorer scores on the same tests when contrasted with living or animate kinds. This pattern is traditionally associated with patients who have suffered from herpes simplex virus encephalitis (HSVE: e.g., Borgo & Shallice, 2001; Gainotti & Silveri, 1996; Sartori & Job, 1988; Warrington & Shallice, 1984) although it has also been reported after head injury (e.g., Farah, Hammond, Mehta, & Ratcliff, 1989; Laiacona, Barbarotto, & Capitani, 1993), cerebrovascular accidents (CVA: e.g., Caramazza & Shelton, 1998; Forde, Francis, Riddoch, Rumiati, & Humphreys, 1997), and dementia of Alzheimer’s type (DAT: e.g., Garrard, Patterson, Watson, & Hodges, 1998; Gonnerman, Andersen, Devlin, Kempler, & Seidenberg, 1997). The opposite dissociation, relatively better performance for living than nonliving kinds, has been reported in only a handful of studies, most often as a consequence of CVA (Hillis & Caramazza, 1991; Sacchett & Humphreys, 1992; Warrington & McCarthy, 1987) in addition to a single patient with progressive atrophy of the left temporal and inferior parietal lobes (Silveri, Gainotti, Perani, Capelletti, Carbone, & Fazio, 1997) and occasionally in patients with DAT (Garrard et al., 1998; Gonnerman et al., 1997). The purpose of the present study was to investigate the relationship between category-specific semantic impairments and semantic dementia. Patients with semantic dementia are relevant to two key themes in the category-specific literature: (1) the sensory-functional theory, and (2) critical neuroanatomical regions. Each of these topics is briefly reviewed below.
