Communication is fundamental to the human condition but is impaired in life-altering ways for more than 2.4 million individuals with aphasia in the United States. Individuals with aphasia identify discourse-level communication (i.e. language in use) as a high priority for treatment. The central premise of most aphasia treatments is that restoring…

Purpose: The purpose of this study was to develop and pilot a novel treatment framework called "BEARS" (Balancing Effort, Accuracy, and Response Speed). People with aphasia (PWA) have been shown to maladaptively balance speed and accuracy during language tasks. BEARS is designed to train PWA to balance speed-accuracy trade-offs and…

Background: The typicality effect is present in neurologically intact populations for natural, ad-hoc, and well-defined categories. Although sparse, there is evidence of typicality effects in persons with chronic stroke aphasia for natural and ad-hoc categories. However, it is unknown exactly what influences the typicality effect in this…

This study examined the time course of object naming in 21 individuals with primary progressive aphasia (PPA) (8 agrammatic (PPA-G); 13 logopenic (PPA-L)) and healthy age-matched speakers (n=17) using a semantic interference paradigm with related and unrelated interfering stimuli presented at stimulus onset asynchronies (SOAs) of -1000, -500, -100…

Many patients with primary progressive aphasia (PPA) are impaired in syntactic production. Because most previous studies of expressive syntax in PPA have relied on quantitative analysis of connected speech samples, which is a relatively unconstrained task, it is not well understood which specific syntactic structures are most challenging for these…

Aphasia recovery after stroke has been the subject of several studies, but in none the deficits on the various linguistic levels were examined, even though in the diagnosis and treatment of aphasia the emphasis lays more and more on these linguistic level disorders. In this observational prospective follow-up study, we explored whether it is…

The "primary systems" view of reading disorders proposes that there are no neural regions devoted exclusively to reading, and therefore that acquired dyslexias should reliably co-occur with deficits in more general underlying capacities. This perspective predicted that surface dyslexia, a selective deficit in reading aloud "exception" words (those…

Word frequency is a powerful predictor of language processing efficiency in healthy individuals and in computational models. Puzzlingly, frequency effects are often absent in stroke aphasia, challenging the assumption that word frequency influences the behavior of any computational system. To address this conundrum, we investigated divergent…

Patients with multimodal semantic impairment following stroke (referred to here as "semantic aphasia" or SA) fail to show the standard effects of frequency in comprehension tasks. Instead, they show absent or even "reverse" frequency effects: i.e., better understanding of less common words. In addition, SA is associated with poor regulatory…

Wernicke's aphasia (WA) is the classical neurological model of comprehension impairment and, as a result, the posterior temporal lobe is assumed to be critical to semantic cognition. This conclusion is potentially confused by (a) the existence of patient groups with semantic impairment following damage to other brain regions (semantic dementia and…

Wernicke's aphasia is a condition which results in severely disrupted language comprehension following a lesion to the left temporo-parietal region. A phonological analysis deficit has traditionally been held to be at the root of the comprehension impairment in Wernicke's aphasia, a view consistent with current functional neuroimaging which finds…

We present a neural network model of learning and processing the English past tense that is based on the notion that experience-dependent cortical development is a core aspect of cognitive development. During learning the model adds and removes units and connections to develop a task-specific final architecture. The model provides an integrated…

Current research on bilingual aphasia highlights the paucity in recommendations for optimal rehabilitation for bilingual aphasic patients (Edmonds & Kiran, 2006; Roberts & Kiran, 2007). In this paper, we have developed a computational model to simulate an English-Spanish bilingual language system in which language representations can vary by age…

This article provides a detailed assessment of patient HT with a history of progressive language deterioration of approximately 6 years presenting now as a fluent jargon aphasic with severe impairment of both speech production and comprehension. Neuropsychological testing of non-verbal cognitive functions showed no impairment, leading to the…

We report the naming performance of a Spanish patient (AQF) suffering from Primary Progressive Aphasia (PPA). AQF's performance revealed a grammatical category-specific deficit, with poorer performance in verb than in noun naming. Furthermore, this dissociation was only present in written naming. Importantly, the patient's dissociation between…