CATEGORY-SPECIFIC FORM-KNOWLEDGE DEFICIT IN A PATIENT WITH HERPES-SIMPLEX VIRUS ENCEPHALITIS

In-depth case study of a herpes simplex virus encephalitis patient who presents with a relatively clear knowledge disorder and anterograde a mnesia in the absence of any other major cognitive deficit. The main n europsychological feature is a category-specific impairment restricted to living things. The patient misnamed pictures of animals and vegeta bles, could not accurately draw animals from memory or verbally descri be their visual appearance, and was not accurate in sorting pictures o f real animals from pictures of unreal animals; conversely, in the sam e tasks her performance with artifactual objects was either errorless or superior to that with animals. We interpret the patient's category- specific deficit as due to a selective disturbance within the structur al description system, rather than a deficit in low-level visual proce ssing or semantic memory. From this case study and a review of other r eported cases we claim that such deficit of form-knowledge is a conseq uence of the extensive lesions that affect bilaterally the inferior pa rts of the temporal lobes. The patient here described thus offers furt her empirical evidence for the crucial role of the inferotemporal cort ex in processing visual knowledge about concepts.