CONCEPTUAL AND LEXICAL ASPECTS OF GESTURE - EVIDENCE FROM APHASIA

The patterns of speech-related (''coverbal'') gestures were investigated in two right-handed aphasic patients, one (PA) with a primary deficit in pre-linguistic, conceptual processing and one (AU) with a primary deficit in lexical retrieval. For reference, one healthy subject was also studied. Body movement during speech was monitored and analysed with an advanced, computerised technique (CODA 3). The physical properties and timing in relation to speech of gestures of the right arm was used to grade gestures for specificity of ideational content. Both patients produced a relatively large amount of gestures, with relatively many content-bearing gestures. The patient with primarily lexical deficits (AU) produced gestures of greater semantic specificity than the patient with primarily conceptual deficits (PA). We conclude that the gestures produced by the patients had different processing origins according to locus of deficits: PA produced more gestures originating in conceptual processing and AU mom gestures originating in lexical processing. By inference, we argue, gesture reflects an effort to facilitate processing in the impaired components.