Neural Mechanisms of Swallowing Dysfunction and Apraxia of Speech in Acute Stroke.

Speech and swallowing utilize overlapping anatomy and are thus inherently related processes. We sought to identify common neural mechanisms between risk of swallowing dysfunction and apraxia of speech (AOS). This was a retrospective analysis using data from a prospectively collected cohort. Left hemisphere stroke patients (68 subjects) tested with the Apraxia Battery for Adults II, a swallow screen, and MRI were included in the study. Main outcome measure was the presence of AOS or aspiration risk after stroke. We identified a significant association between AOS measures and increased aspiration risk (defined by failed swallow screen; p = 0.04; OR 5.2). Lesions in pars opercularis of Broca's area (BA 44) were associated with both AOS (p = 0.044; OR 9.7) and increased aspiration risk (p = 0.04; OR 5) but deficits rarely co-occurred in the same cases. Lesions in left premotor cortex (BA 6) were not significantly associated with increased aspiration risk (p = 0.06; OR 3.3) but were significantly associated with AOS (p = 0.008; OR 7). Impaired swallowing function was also associated with lesions in Wernicke's area (BA 22; p = 0.05; OR 3.5) and pars triangularis (BA 45; p = 0.02; OR 6.8). AOS and risk of aspiration are associated in patients with acute left hemisphere stroke. Acute infarct in the pars opercularis of Broca's area is associated with both deficits, though they rarely co-occur in the same individual. The co-occurrence of AOS and risk of aspiration likely reflects dependence on closely related neural structures.

Impaired Recognition of Emotional Faces after Stroke Involving Right Amygdala or Insula.

Despite its basic and translational importance, the neural circuitry supporting the perception of emotional faces remains incompletely understood. Functional imaging studies and chronic lesion studies indicate distinct roles of the amygdala and insula in recognition of fear and disgust in facial expressions, whereas intracranial encephalography studies, which are not encumbered by variations in human anatomy, indicate a somewhat different role of these structures. In this article, we leveraged lesion-mapping techniques in individuals with acute right hemisphere stroke to investigate lesions associated with impaired recognition of prototypic emotional faces before significant neural reorganization can occur during recovery from stroke. Right hemisphere stroke patients were significantly less accurate than controls on a test of emotional facial recognition for both positive and negative emotions. Patients with right amygdala or anterior insula lesions had significantly lower scores than other right hemisphere stroke patients on recognition of angry and happy faces. Lesion volume within several regions, including the right amygdala and anterior insula, each independently contributed to the error rate in recognition of individual emotions. Results provide additional support for a necessary role of the right amygdala and anterior insula within a network of regions underlying recognition of facial expressions, particularly those that have biological importance or motivational relevance and have implications for clinical practice.

Knowledge and Attitudes About Breast Cancer in Limpopo, South Africa.

PURPOSE: Breast cancer survival is unacceptably low in many low-resource settings, including rural South Africa, where access to screening and treatment services is limited. To describe the context for implementing an early detection program, we assessed knowledge and attitudes toward breast cancer risk, early detection, and treatment. METHODS: We conducted a cross-sectional survey among 243 women presenting to Hlokomela Clinic in Hoedspruit, South Africa, during April and May 2016. We used quantitative and qualitative analyses to determine levels of knowledge of risk factors, symptoms, and treatment of breast cancer, as well as experience with and attitudes toward detection and treatment methods. RESULTS: Thirty-one percent of women correctly identified at least six of 12 risk factors for breast cancer, and 53.1% identified breast lumps as an important symptom. Although > 97% of women stated that self-breast examination and early detection were highly important and that they would seek care for changes in their breasts, only 33.3% of women reported performing self-breast examination, and only 24.3% reported receiving a clinical breast examination. Age and education were not associated with knowledge, and level of knowledge did not predict care-seeking behaviors or attitudes. CONCLUSION: Although women demonstrated moderate levels of knowledge of breast cancer symptoms and risk factors and the importance of early detection, few women reported seeking services. These data demonstrate sufficient levels of knowledge and positive attitudes toward care seeking and suggest both a need and readiness for increased access to cost-effective services to facilitate early diagnosis and improved outcomes.

Chronic apraxia of speech and Broca's area.

BACKGROUND AND PURPOSE: Apraxia of speech (AOS) is an impairment of motor planning and programming of speech articulation and is often considered an important stroke syndrome, localizable to Broca's area. However, an influential study raised doubts on this localization and reported that AOS is attributable to lesions of the anterior insula, based on an association between chronic AOS and anterior insula lesions. We hypothesized that chronic AOS is associated with large lesions (which include the insula) or lesions to Broca's area. Method- We tested 34 participants with chronic left supratentorial stroke on an AOS battery and obtained concurrent magnetic resonance imaging. We evaluated associations between AOS and locations and volume of infarct. RESULTS: The presence of chronic AOS (n=17) was associated with volume of infarct, but was also associated with infarct in Broca's area (and several other regions, but not anterior insula) in both volume- and age-adjusted linear regression and the dichotomous analysis. Carotid dissection was more common, and cardioembolism less common, as a cause of stroke in patients with AOS compared with those without. Severity of AOS was also strongly associated with lesion volume. CONCLUSIONS: Persistence of AOS after 12 months is associated with large left hemispheric stroke and strokes that involve Broca's area or other relatively anterior areas to which it is structurally or functionally connected. Patients with such lesions may benefit from early training in the use of technologies to support speech production and communication.

Motor extinction in distinct reference frames: a double dissociation.

OBJECTIVE: Test the hypothesis that right hemisphere stroke can cause extinction of left hand movements or movements of either hand held in left space, when both are used simultaneously, possibly depending on lesion site. METHODS: 93 non-hemiplegic patients with acute right hemisphere stroke were tested for motor extinction by pressing a counter rapidly for one minute with the right hand, left hand, or both simultaneously with their hands held at their sides, or crossed over midline. RESULTS: We identified two distinct types of motor extinction in separate patients; 20 patients extinguished left hand movements held in left or right space (left canonical body extinction); the most significantly associated voxel cluster of ischemic tissue was in the right temporal white matter. Seven patients extinguished either hand held in left space (left space extinction), and the most significantly associated voxel cluster of ischemic tissue was in right parietal white matter. CONCLUSIONS: There was a double dissociation between left canonical body extinction and left space motor extinction. Left canonical body extinction seems to be associated with more dorsal (parietal) ischemia, and left canonical body extinction seems to be associated with more ventral (temporal) ischemia.

Reperfusion of specific cortical areas is associated with improvement in distinct forms of hemispatial neglect.

OBJECTIVE: To test the hypothesis that restoring blood flow to specific right cortical regions in acute stroke results in improvement in distinct forms of hemispatial neglect distinguished by reference frame: viewer-centered versus stimulus-centered neglect. METHODS: Twenty five patients with acute right stroke were evaluated at Day 1 and Day 3-5 with a battery of neglect tests and Diffusion- and Perfusion-Weighted MR Imaging. Multivariate linear regression analysis revealed Brodmann areas (BAs) where reperfusion predicted degree of improvement in scores on each type of neglect, independently of reperfusion of other areas, total change in the volume of infarct or hypoperfusion, and age. RESULTS: Reperfusion of dorsal frontoparietal cortex (including BAs 40, 46, and 4) independently predicted improvement in viewer-centered neglect, such as detecting stimuli on left in line cancellation and scene copying (r=.951; p<.0001). Reperfusion of a more ventral temporo-occipital cortex, including right BAs 37, 38, 21 and 18, independently contributed to improvement in stimulus-centered neglect, such as detecting left gaps in circles (r=.926; p<.0001). Reperfusion of right midfusiform gyrus (temporal occipital cortex), change in total volume of ischemia, change in volume of hypoperfusion and age predicted degree of improvement in reading (reduction in "neglect dyslexic" errors; r=.915; p<.0001). Results demonstrate that reperfusing specific cortical regions yields improvement in different types of neglect.

Asyntactic comprehension, working memory, and acute ischemia in Broca's area versus angular gyrus.

We evaluated sentence comprehension of variety of sentence constructions and components of short-term memory (STM) in 53 individuals with acute ischemic stroke, to test some current hypotheses about the role of Broca's area in these tasks. We found that some patients show structure-specific, task-independent deficits in sentence comprehension, with chance level of accuracy on passive reversible sentences, more impaired comprehension of object-cleft than subject-cleft sentences, and more impaired comprehension of reversible than irreversible sentences in both sentence-picture matching and enactment tasks. In a dichotomous analysis, this pattern of "asyntactic comprehension" was associated with dysfunctional tissue in left angular gyrus, rather than dysfunctional tissue in Broca's area as previously proposed. Tissue dysfunction in left Brodmann area (BA) 44, part of Broca's area, was associated with phonological STM impairment defined by forward digit span≤4. Verbal working memory (VWM) defined by backward digit span≤2 was associated with tissue dysfunction left premotor cortex (BA 6). In a continuous analysis, patients with acute ischemia in left BA 44 were impaired in phonological STM. Patients with ischemia in left BA 45 and BA 6 were impaired in passive, reversible sentences, STM, and VWM. Patients with ischemia in left BA 39 were impaired in passive reversible sentences, object-cleft sentences, STM, and VWM. Therefore, various components of working memory seem to depend on a network of brain regions that include left angular gyrus and posterior frontal cortex (BA 6, 44, 45); left BA 45 and angular gyrus (BA 39) may have additional roles in comprehension of syntax such as thematic role checking.