Category-specific treatment of a lexical-semantic deficit: a single case study of global aphasia.

The aim of this study was to improve the comprehension of single items in a subject with global aphasia. Existing models of semantic organisation were used to inform and guide the treatment programme. Detailed pre-therapy testing suggested a severe comprehension deficit with an inability to obtain a precise semantic specification of the items, irrespective of modality of input. A category-specific hierarchical treatment programme including generic and specific details about items was implemented through various exercises and drills. Post-therapy testing revealed a significant improvement on treated and untreated items of treated categories but limited generalisation to items in untreated categories. Improvement in the subject's general semantic abilities was also documented following treatment. The results, which are shown to be a direct consequence of the intervention programme, lend support to the categorical and hierarchical view of the organisation of semantics and provide a basis for future rehabilitation studies in this area.