Abstract:

Aphasia is an acquired language disorder resulting from a focal brain lesion in the left hemisphere. Language in aphasia is characterized by deficits in lexical retrieval, comprehension of auditory information, repetition and fluency. Verbal output may contain errors in semantic, phonologic, and speech quanta (amount and ease of verbal production). Neuroplasticity in aphasia recovery can be an adaptive process of reactivation or reorganization, but can be maladaptiveand result in persistent errors. Thus, it is important to understand the reorganization of the brain following stroke in terms of adequate and impaired performance. Here we focus on semantics in connected language performance in 22 people with aphasia (PWA) and 18 healthy control participants. Semantics, in this study, is assess in a picture description task for: semantic errors (SE) or paraphasias, significant pauses indicative of lexical retrieval deficits, aphasia severity, and the variety of different types of words used (type-toke ratio, TTR). We investigate the relationship between the brain regions responsible for semantics (a semantic brain network), and how these relationships are altered in aphasia, using resting-state functional magnetic resonance imaging (rsfMRI).