Semantic memory deficits following Herpes Simplex Encephalitis (HSE). A single-case study

Semantic memory disorders following HSE are frequently characterised by the category specificity effect, namely the living things domain more disrupted then the non-living things one. Whether this is due to a categorical organisation of the semantic system or to a deficit in processing basic information necessary for item identification, is still under debate. We tested these two hypotheses. A single case study of HSE with category specificity effect was undertaken. The patient was studied six months post-onset during rehabilitation at the Clinical Neuropsychology Office of our Rehabilitation Unit. The patient was tested on several tasks tapping semantic representation of living thing, "mass" kind, and non-living thing domains. Besides classic category specificity impairment, the patient presented consistent deficit in processing semantic features of items when sensory attributes were presented compared to functional ones irrespectively of the item domain class (living, "mass" kinds, or non-living things). These findings suggest that the category specificity effect is not determined by a categorical deficit within the semantic system but is rather due to impairment in processing sensory attributes that underpin semantic representation. This poses the theoretical basis for cognitive rehabilitation of semantic memory deficits following HSE.