An on-line study of grammaticality judgements in normal and aphasic speakers of Italian

Abstract

It has been widely argued that Broca's aphasics suffer from a loss of grammatical knowledge, accounting for the co-occurrence of expressive agrammatism (i.e. reduced, telegraphic speech with few inflections and function words) and specific problems with grammatical elements in sentence comprehensive. This idea is challenged by cross-linguistic studies showing that agrammatic patients retain detailed structural properties of their native language in comprehension and production, and by studies showing that these patients can make judgements of grammaticality that would be difficult to explain if they had lost grammatical knowledge. The present study compares sensitivity to errors of subject-verb and noun-adjective agreement in Italian, in agrammatic Broca's aphasics, fluent Wernicke's and anomic aphasics, college students and elderly controls. Stimuli vary in amount of grammatical context (i.e. the number of cues available to signal an agreement contrast), and in degree of violation (i.e. violation of only one morphological dimension, e.g. person, number or gender, vs violations that involve more than one dimension). Errors are detected ‘on-line’, yielding information about reaction time as well as accuracy. Results confirm that Broca's aphasics perform above chance, at levels equal to fluent patients with expressive agrammatism, providing further evidence against central agrammatism. Differential effects of grammatical context and degree of violation are observed in accuracy and reaction times for normals and patient groups. Implications for processing accounts of language breakdown in aphasia are discussed.