In standard models of language production or comprehension, the elements which are retrieved from memory and combined into a syntactic structure are "lemmas" or "lexical items". Such models implicitly take a "lexicalist" approach, which assumes that lexical items store meaning, syntax, and form together, that…

It is well known that persons with aphasia (PWA) demonstrate deficits in sentence processing. Specifically, many show difficulties with syntactic re-analysis, or the ability to revise one's interpretation of a sentence due to a temporary ambiguity. Emerging evidence suggests that structural priming, individuals' tendency to unconsciously re-use a…

Background: The most common cause of aphasia is a left middle cerebral artery stroke affecting the left perisylvian region of the brain. The perisylvian region is critical for supporting phonological processing, and damage to this region results in difficulty with retrieving and manipulating speech sounds. The impact of weakened phonology has been…

The goal of this dissertation was to find converging evidence from behavioral and neuroimaging analyses of the mechanisms of orthographic integration with general language processes. By examining orthography effects, covert influences of orthography on non-written tasks, in participants with aphasia, we attempt to elucidate the nature of…

Primary progressive aphasia (PPA) is an acquired neurodegenerative syndrome that has specific and devastating effects on an individual's speech and language ability. Based on a detailed assessment of behavior and cognition, combined with structural neuroimaging data and pathological evidence, PPA is typically classified into three variants: the…

Producing a sentence involves encoding a preverbal message into a grammatical structure by retrieving lexical items and integrating them into a functional (semantic-to-grammatical) structure. Individuals with agrammatism are impaired in this grammatical encoding process. However, it is unclear what aspect of grammatical encoding is impaired and…

This project examines spoken language comprehension in Broca's aphasia, a non-fluent language disorder acquired subsequent to stroke. Broca's aphasics demonstrate impaired comprehension for complex sentence constructions. To account for this deficit, one current processing theory claims that Broca's patients retain intrinsic linguistic knowledge,…

Agrammatism is a frequent sequela of Broca's aphasia that manifests itself in omission and/or substitution of the grammatical morphemes in spontaneous and constrained speech. The hierarchical structure of syntactic trees has been proposed as an account for difficulty across grammatical morphemes (e.g., tense, agreement, and negation). Supporting…