Agrammatism and adaptation theory

Abstract

Ability to process grammatical structures was studied in 14 agrammatic speakers, 11 other non-fluent aphasics, five fluent aphasics and 10 normal controls. Adaptation theory maintains that spontaneous speech gives a poor indication of the underlying impairment, because agrammatic patients adopt a strategy of producing elliptical speech to avoid making errors. It was therefore predicted that the pattern of grammatical errors should look different in tasks that minimized or prevented adaptation, such as elicited speech, written sentence ordering and cloze tasks. The grammatical profile of agrammatic aphasics did show some change under cliciting conditions; they produced a higher proportion of verbs in these circumstances and showed some ability to produce active transitive constructions that were not seen in spontaneous speech. However, elictation had no effect on sentence length or complexity or use of grammatical morphemes. Paragrammatic errors were seen in both agrammatic and fluent aphasics under eliciting conditions, but were rare in both groups. In contrast to previous studies of German and Dutch aphasic patients, it was found that omission of obligatory inflectional endings was particularly common in agrammatic speakers, both in spontaneous speech and on a cloze task where such omissions could not be regarded as strategic use of ellipsis.