Ageing effects on word production processes: an ERP topographic analysis
Résumé
The increasing word-finding difficulty is one of the most investigated characteristics of language ageing. The transmission deficit model postulates an age-related weakening in the pathway from lexicon to phonology, leading to insufficient priming of the complete phonology. To bring neurophysiological evidence of age-related modifications in word production, we investigated the inter-age time course of ERPs in picture naming compared to picture-word verification, where lexical-phonological processes are not involved. Only marginal age-related differences in RTs were found in picture naming. Older adults showed lower accuracy in picture naming, but higher accuracy in picture-word verification. Between-age ERP divergences were observed in an early time window associated with semantic processes. In picture naming, age differences in ERP amplitudes were also observed in a later time window compatible with phonological processing. Results suggest that modifications in word production could stem from age-related changes affecting the processing dynamics in the semantic system.