“Categorical Sense in Aphasics”

Abstract

     The aim of the present research consisted in studying if in aphasia the signs of semantic impairment that can be observed in word finding or confrontation naming are related to how lexical components are organized. Twenty aphasic patients with unilateral left hemisphere lesions, ten non-aphasic patients with unilateral right or left hemisphere lesions and ten demented patients with neurological disease were assessed on a battery of non-verbal test designed to investigate semantic categorization in mental lexicon. The aphasic patients had been divided into three clinical syndromes : 11 Broca's, 6 Wernicke's and 3 amnesic aphasia. A test of semantic categorization was afforded by the “Visual Reception” and “Visual Association” subtests of the Illinois Test of Psycholinguistic Abilities (ITPA). The ITPA was designed as a diagnostic test of language and related perceptual-communication process. The “Visual Reception” subtest requires the subject to match two exemplars of the same semantic category, independently of perceptual representation. The “Visual Association” subtest samples a variety of other meta-semantic relations.
The non-aphasic group showed good performance and was equally competence to decode and associate picture over the level of a 8 year old child.
The aphasic group was equally competence to decode picture at the level of a 9 year old child, but was significantly impaired on the test of picture-association. The demented group exhibited severe impairment across subtests of the ITPA. Semantic errors in the “Visual Association” subtest obtained by aphasic aphasic showed a prevalence of affective recognition. It was suggested that the lexical structures produced by aphasics were semantically restricted.