Regional brain aging: premature aging of the domain general system predicts aphasia severity.

Premature brain aging is associated with poorer cognitive reserve and lower resilience to injury. When there are focal brain lesions, brain regions may age at different rates within the same individual. Therefore, we hypothesize that reduced gray matter volume within specific brain systems commonly associated with language recovery may be important for long-term aphasia severity. Here we show that individuals with stroke aphasia have a premature brain aging in intact regions of the lesioned hemisphere. In left domain-general regions, premature brain aging, gray matter volume, lesion volume and age were all significant predictors of aphasia severity. Increased brain age following a stroke is driven by the lesioned hemisphere. The relationship between brain age in left domain-general regions and aphasia severity suggests that degradation is possible to specific brain regions and isolated aging matters for behavior.

The effects of emotional stimuli on Word retrieval in people with aphasia.

PURPOSE: Prior studies have shown that people with aphasia (PWA) have demonstrated superior language performance for emotional compared to nonemotional stimuli on a range of tasks, including auditory comprehension, verbal pragmatics, repetition, reading, and writing. However, studies on word retrieval, specifically, have suggested a possible interference effect of emotion on naming. The purpose of this study was to examine the effect of the emotional valence of stimuli on word retrieval in a series of naming tasks in PWA. METHOD: Thirteen PWA and 13 neurotypical controls participated in four single-word naming tasks, including 1) object picture naming, 2) action picture naming, 3) category-member generation, and 4) verb generation. Each task included three valence sets of positively-, negatively-, and neutrally-rated pictures or words, which were obtained from the standardized International Affective Picture System (Lang et al., 2008) and the Affective Norms for Emotional Words (Bradley and Lang, 1999) databases. Accuracy and reaction time (RT) were measured and compared across groups, tasks, and valence sets. RESULTS: Emotional stimuli, especially negative stimuli, resulted in worse naming performance, as measured by accuracy and RT, compared to nonemotional stimuli in PWA and neurotypical controls. This effect was relatively robust across the four naming tasks. In most cases, negative stimuli resulted in lower accuracy and slower RT than positive stimuli. CONCLUSIONS: These findings suggest that stimulus valence may interfere with word retrieval for PWA and neurotypical adults and that this effect is robust across different types of naming tasks that vary by word class (nouns versus verbs) and stimulus type (pictures versus words). Negative stimuli resulted in worse naming performance than positive stimuli. These results suggest that emotionality of stimuli is an important variable to consider in word retrieval research.

Bridging the Gap: Association between Objective and Subjective Outcomes of Communication Performance in People with Parkinson's Disease Evaluated for Deep Brain Stimulation.

Background: Decrements in verbal fluency following deep brain stimulation (DBS) in people with Parkinson's disease (PwP) are common. As such, verbal fluency tasks are used in assessing DBS candidacy and target selection. However, the correspondence between testing performance and the patient's perception of communication abilities is not well-established. Methods: The Communication Participation Item Bank (CPIB) was administered to 85 PwP during pre-DBS neuropsychological evaluations. Central tendencies for CPIB responses and correlations between CPIB total scores, clinical and demographic factors, and language-based tasks were examined. Results: Most PwP indicated some degree of communication interference on the CPIB. Worse scores on semantic fluency and greater motor impairment were associated with more communication interference. Conclusions: Our findings suggest an incomplete correspondence between commonly used language-based tests and patient-reported outcomes of communication abilities. The need for a functional communication instrument that reflects the different aspects of communication abilities in functional contexts is emphasized.

Diabetes, brain health, and treatment gains in post-stroke aphasia.

In post-stroke aphasia, language improvements following speech therapy are variable and can only be partially explained by the lesion. Brain tissue integrity beyond the lesion (brain health) may influence language recovery and can be impacted by cardiovascular risk factors, notably diabetes. We examined the impact of diabetes on structural network integrity and language recovery. Seventy-eight participants with chronic post-stroke aphasia underwent six weeks of semantic and phonological language therapy. To quantify structural network integrity, we evaluated the ratio of long-to-short-range white matter fibers within each participant's whole brain connectome, as long-range fibers are more susceptible to vascular injury and have been linked to high level cognitive processing. We found that diabetes moderated the relationship between structural network integrity and naming improvement at 1 month post treatment. For participants without diabetes (n = 59), there was a positive relationship between structural network integrity and naming improvement (t = 2.19, p = 0.032). Among individuals with diabetes (n = 19), there were fewer treatment gains and virtually no association between structural network integrity and naming improvement. Our results indicate that structural network integrity is associated with treatment gains in aphasia for those without diabetes. These results highlight the importance of post-stroke structural white matter architectural integrity in aphasia recovery.

Neural network bases of thematic semantic processing in language production.

Semantic processing is a central component of language and cognition. The anterior temporal lobe is postulated to be a key hub for semantic processing, but the posterior temporoparietal cortex is also involved in thematic associations during language. It is possible that these regions act in concert and depend on an anteroposterior network linking the temporal pole with posterior structures to support thematic semantic processing during language production. We employed connectome-based lesion-symptom mapping to examine the causal relationship between lesioned white matter pathways and thematic processing language deficits among individuals with post-stroke aphasia. Seventy-nine adults with chronic aphasia completed the Philadelphia Naming Test, and semantic errors were coded as either thematic or taxonomic to control for taxonomic errors. Controlling for nonverbal conceptual-semantic knowledge as measured by the Pyramids and Palm Trees Test, lesion size, and the taxonomic error rate, thematic error rate was associated with loss of white matter connections from the temporal pole traversing in peri-Sylvian regions to the posterior cingulate and the insula. These findings support the existence of a distributed network underlying thematic relationship processing in language as opposed to discrete cortical areas.

A Scoping Review on the Effects of Emotional Stimuli on Language Processing in People With Aphasia.

PURPOSE: Emotional stimuli have been shown to influence language processing (both language comprehension and production) in people with aphasia (PWA); however, this finding is not universally reported. Effects of emotional stimuli on language performance in PWA could have clinical and theoretical implications, yet the sparsity of studies and variability among them make it difficult to appraise the significance of this effect. The purpose of this scoping review was to (a) determine the extent and range of research examining the effect of emotional stimuli on language processing in PWA, (b) summarize and evaluate research findings, and (c) identify gaps in the literature that may warrant future study. METHOD: PsycINFO, PubMed, Web of Science, and Cumulative Index to Nursing and Allied Health Literature databases were systematically searched for articles that compared performance in response to emotional and nonemotional stimuli on at least one language measure in one or more adults with aphasia. Data related to methods and results were extracted from each article and charted in Excel. RESULTS: Five hundred forty unique articles were found, and 18 articles, consisting of 19 studies, met inclusion/exclusion criteria for this review. Of the 19 studies included, 11 studies reported enhanced performance on a language task for emotional compared to nonemotional stimuli, seven reported no difference, and one reported worse performance for emotional compared to nonemotional stimuli. Possible modulating variables such as task type, measurement, stimulus characteristics, and sample characteristics are discussed along with gaps in the literature. CONCLUSION: The extent of research in this area is sparse; however, there does appear to be some early evidence for better performance in response to emotional over nonemotional stimuli in PWA for some, but not all, language processes investigated.