Regions of Dysfunctional Neural Tissue Associated with Impairment of the Graphemic Buffer in Spelling

The graphemic buffer is a working memory component of the spelling system that temporarily stores the sequence of graphemes while each grapheme is written or spelled aloud. We evaluated 331 patients with left hemisphere stroke on oral and written spelling to dictation, and written picture naming tasks and MRI including within 48 hours of stroke onset. Spelling performance was examined to identify presence or absence of graphemic buffer deficit. A voxel-wise chi-square map revealed that graphemic buffer deficits were associated with ischemia in pre- and post-central gyri, posterior inferior frontal and lateral occipital cortex

Representation of Grammatical Categories of Words in the Brain

We report the performance of a patient who, as a consequence of left frontal and temporoparietal strokes, makes far more errors on nouns than on verbs in spoken output tasks, but makes far more errors on verbs than on nouns in written input tasks. This double dissociation within a single patient with respect to grammatical category provides evidence for the hypothesis that phonological and orthographic representations of nouns and verbs are processed by independent neural mechanisms. Furthermore, the opposite dissociation in the verbal output modality, an advantage for nouns over verbs in spoken tasks, by a different patient using the same stimuli has also been reported (Caramazza & Hillis, 1991). This double dissociation across patients on the same task indicates that results cannot be ascribed to "greater difficulty" with one type of stimulus, and provides further evidence for the view that grammatical category information is an important organizational principle of lexical knowledge in the brain.Psycholog

Effects of Separate Treatments for Distinct Impairments Within the Naming Process

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Paucity vs. Verbosity: Another Analysis of Right Hemisphere Communication Deficits

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Model-Driven Remediation of Dysgraphia

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Resting state correlates of picture description informativeness in left vs. right hemisphere chronic stroke

IntroductionDespite a growing emphasis on discourse processing in clinical neuroscience, relatively little is known about the neurobiology of discourse production impairments. Individuals with a history of left or right hemisphere stroke can exhibit difficulty with communicating meaningful discourse content, which implies both cerebral hemispheres play a role in this skill. However, the extent to which successful production of discourse content relies on network connections within domain-specific vs. domain-general networks in either hemisphere is unknown.MethodsIn this study, 45 individuals with a history of either left or right hemisphere stroke completed resting state fMRI and the Cookie Theft picture description task.ResultsParticipants did not differ in the total number of content units or the percentage of interpretative content units they produced. Stroke survivors with left hemisphere damage produced significantly fewer content units per second than individuals with right hemisphere stroke. Intrinsic connectivity of the left language network was significantly weaker in the left compared to the right hemisphere stroke group for specific connections. Greater efficiency of communication of picture scene content was associated with stronger left but weaker right frontotemporal connectivity of the language network in patients with a history of left hemisphere (but not right hemisphere) stroke. No significant relationships were found between picture description measures and connectivity of the dorsal attention, default mode, or salience networks or with connections between language and other network regions.DiscussionThese findings add to prior behavioral studies of picture description skills in stroke survivors and provide insight into the role of the language network vs. other intrinsic networks during discourse production

Current Approaches to the Treatment of Post-stroke Aphasia

Aphasia, impairment of language after stroke or other neurological insult, is a common and often devastating condition that affects nearly every social activity and interaction. Behavioral speech and language therapy is the mainstay of treatment, although other interventions have been introduced to augment the effects of the behavioral therapy. In this narrative review, we discuss advances in aphasia therapy in the last 5 years and focus primarily on properly powered, randomized, controlled trials of both behavioral therapies and interventions to augment therapy for post-stroke aphasia. These trials include evaluation of behavioral therapies and computer-delivered language therapies. We also discuss outcome prediction trials as well as interventional trials that have employed noninvasive brain stimulation, or medications to augment language therapy. Supported by evidence from Phase III trials and large meta-analyses, it is now generally accepted that aphasia therapy can improve language processing for many patients. Not all patients respond similarly to aphasia therapy with the most severe patients being the least likely responders. Nevertheless, it is imperative that all patients, regardless of severity, receive aphasia management focused on direct therapy of language deficits, counseling, or both. Emerging evidence from Phase II trials suggests transcranial brain stimulation is a promising method to boost aphasia therapy outcomes

The Role of Brodmann Area 47 in Acute Stroke Patients with Language Impairment

A recent study in chronic stroke patients found that left Brodmann area 47 was among the most commonly lesioned area (more commonly than Brodmann area 44/45) in patients with chronic deficits in reading, naming, and repetition. We hypothesized that the same would not be true in acute stroke; that left BA 44 and 45 would be more commonly associated with these acute lexical deficits. We confirmed this hypothesis and speculate that left BA 47 is an area is critical for recovery of lexical production, perhaps because it can assume lexical production when BA 44/45 are damaged when it is spared