Effects of age and language on co-speech gesture production: an investigation of French, American, and Italian children's narratives.

The aim of this paper is to compare speech and co-speech gestures observed during a narrative retelling task in five- and ten-year-old children from three different linguistic groups, French, American, and Italian, in order to better understand the role of age and language in the development of multimodal monologue discourse abilities. We asked 98 five- and ten-year-old children to narrate a short, wordless cartoon. Results showed a common developmental trend as well as linguistic and gesture differences between the three language groups. In all three languages, older children were found to give more detailed narratives, to insert more comments, and to gesture more and use different gestures--specifically gestures that contribute to the narrative structure--than their younger counterparts. Taken together, these findings allow a tentative model of multimodal narrative development in which major changes in later language acquisition occur despite language and culture differences.

Coverbal gestures in Alzheimer's type dementia.

Patterns of conversational gestures were analysed in subjects with Alzheimer's type dementia (DAT), fluent aphasics with a primarily lexical-semantic deficit (FA) and normal subjects. The FA subjects produced twice as many gestures as the normal participants with a normal percentage of gestures that showed semantic features of the lexical items in concurrent speech (iconic). A comparable lexical-semantic deficit together with a deficit in conceptual organisation of information corresponded to a normal gesturing rate in the DAT subjects; however, the percentage of iconic gestures was reduced. Gestures were also analysed in four DAT patients whose communicative performance indicated primarily lexical-semantic (2 patients) or conceptual deficit (2 patients). In the two DAT patients with lexical-semantic deficit, the gesture pattern was like that of the FA patients; in the other two, the pattern of the DAT group was observed. These results agree with previous findings that DAT "empty" speech corresponds to reduced production of gestures showing semantic features (Glosser et al., 1998). However, the comparison between DAT with primarily lexical-semantic or conceptual deficits indicates that the nature of the cognitive impairment underlying poor information content and lack of reference in DAT discourse constrains the production of conversational gestures by patients with this disease. These findings are at variance with the hypothesis of parallel dissolution of speech and gestures in language disorders after brain damage (Cicone et al., 1979; McNeill, 1992; Glosser et al., 1998).