Semantic weight and verb retrieval in aphasia

• Published in: Brain and language 2006-06, Vol.97 (3), p.266-278
• Main Authors: Barde, Laura H.F., Schwartz, Myrna F., Boronat, Consuelo B.
• Format: Article
• Language: English
• Subjects: Adult; Aged; Agrammatism; Aphasia; Aphasia - diagnosis; Aphasia - epidemiology; Aphasia - physiopathology; Aphasia, Broca - epidemiology; Biological and medical sciences; Brain; Brain damage; Disorders of higher nervous function. Focal brain diseases. Central vestibular syndrome and deafness. Brain stem syndromes; Female; Functional Laterality - physiology; Grammar; Humans; Language Processing; Lexical access; Light verbs; Male; Medical sciences; Middle Aged; Nervous system (semeiology, syndromes); Neurology; Neuropsychological Tests; Nouns; Semantic processing; Semantic weight; Semantics; Severity of Illness Index; Speech production; Syntax; Verb complexity; Verb production; Verb weight; Verbs; Vocabulary
• ISSN: 0093-934X; 1090-2155
• DOI: 10.1016/j.bandl.2005.11.002

Individuals with agrammatic aphasia may have difficulty with verb production in comparison to nouns. Additionally, they may have greater difficulty producing verbs that have fewer semantic components (i.e., are semantically “light”) compared to verbs that have greater semantic weight. A connectionist verb-production model proposed by Gordon and Dell (2003) learns through error correction to “divide the labor” between syntax and semantics. Verbs that are semantically heavier come to depend less on syntax and more on semantics. For lighter verbs, the reverse is true. We performed this study to clarify the role of semantic weight in aphasic verb production and to test the prediction from Gordon and Dell that a brain lesion that impairs the syntactic input to verb retrieval will impair lighter verbs more than heavier ones. Consistent with this prediction, we found that the decrement for lighter verbs was present in a group with agrammatic aphasia but not in a matched group without agrammatism.