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OBJECTIVE: Training clinician-scientists is a primary objective of many academic neurology departments, as these individuals are uniquely positioned to perform insightful clinical or laboratory-based research informed both by clinical knowledge and their own experiences caring for patients. Despite its importance, training clinician-scientists has perhaps never been so challenging. The National Institute of Neurologic Disorders and Stroke (NINDS) R25 program was designed in an attempt to support these individuals, decrease the time needed to obtain National Institutes of Health K awards, and to help educate a cohort of trainees preparing for a career in academic neurology. We endeavored to describe the structure and features of the program while examining its outcomes. METHODS: R25 outcome data from 2009 to 2024 were reviewed. Statistical comparisons were made using 2-sided Mann-Whitney U testing. RESULTS: A total of 67% of adult neurologists who received an R25 had a successful application for a National Institutes of Health K award compared with 45% of adult neurologists who had not received R25 support (p < 0.0001). Among child neurologists, 73% who applied went on to receive K funding after R25 support, compared with 45% who had not been part of the R25 program (p < 0.001). The average time between completion of residency and obtaining a K award for R25 participants was decreased by 26 months among those with an MD/PhD degree, and 32 months for those with an MD degree compared with non-R25 individuals. INTERPRETATION: The R25 program has been successful in achieving its training goals, but stands as only one component of support for aspiring clinician-scientists. Investments and commitments made by academic neurology departments are key to supporting this success. ANN NEUROL 2024.
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BACKGROUND: Combined quantitative susceptibility mapping and R2* relaxometry can distinguish iron and myelin components in ischemic lesions. We aimed to investigate whether longitudinal changes in magnetic susceptibility and R2* values within ischemic lesions were associated with neurological outcomes. METHODS: In this single-center prospective study, we included patients, 20 to 90 years of age, who were consecutively admitted to the stroke care unit between August 2020 and March 2022 due to acute ischemic stroke. The participants underwent 2 instances of quantitative susceptibility mapping and R2* relaxometry scanning before and after stroke rehabilitation. We compared the changes in these quantitative measures across different subtypes of acute ischemic stroke. Multiple linear regression models were used to investigate the associations between the National Institutes of Health Stroke Scale scores and the mean magnetic susceptibility and R2* values in ischemic lesions. RESULTS: Among a total of 112 patients with acute ischemic stroke, 32 participants (aged 73.3±9.4 years; 20 men and 12 women) were evaluated. The median time from stroke onset to the first imaging was 5 days and that to the second imaging was 102 days. The changes in magnetic susceptibility values of branch atheromatous disease were higher than those of cardioembolism (mean difference, 0.018 [95% CI, 0.009-0.027] ppm; P<0.001) and lacunar (mean difference, 0.013 [95% CI, 0.005-0.020] ppm; P=0.004). Across all patients, the changes in National Institutes of Health Stroke Scale scores were associated with those of magnetic susceptibility values (coefficient, 0.311 [95% CI, 0.098-0.520]; P=0.017) but not with R2* values (coefficient, 0.114 [95% CI, -0.127 to 0.345]; P=0.291). CONCLUSIONS: The longitudinal changes in the magnetic susceptibility values within ischemic lesions were associated with neurological outcomes during the restorative stages poststroke in patients experiencing acute ischemic stroke. REGISTRATION: URL: https://www.umin.ac.jp/ctr/; Unique identifier: UMIN000050719.
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Isquemia Encefálica , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Masculino , Humanos , Femenino , Isquemia Encefálica/diagnóstico por imagen , Proyectos Piloto , Estudios Prospectivos , Hierro , Accidente Cerebrovascular/diagnóstico por imagen , Isquemia/diagnóstico por imagenRESUMEN
BACKGROUND: The National Institutes of Health Stroke Scale is a widely accepted tool for structured graded neurological examination of stroke or suspected stroke in the hyperacute setting. Concerns have arisen about the use of its picture stimuli in a contemporary and global health context. Here, we present new stimuli prepared to serve the needs of stroke providers worldwide: the precarious painter image description and updated objects for naming. METHODS: This was a validation study of 101 healthy fluent English speakers. Participants were reached by the Johns Hopkins Outpatient Center, the University of South Carolina, and Prisma Health from 2022 to 2023 and included residents of the United States, Germany, Canada, the United Kingdom, Australia, and Zambia. Participants were recorded in person or via video conferencing when asked to describe the new picture, while a subset named seven illustrations. Multivariate analyses of variance were used for primary analyses. In a complementary investigation, 299 attendees of the 2023 International Stroke Conference were asked about their preference for the existing or new stimuli and why. RESULTS: Each of the 44 content units from the picture description was included by at least 5% of respondents in the demographically representative subsample. Performance was similar across healthy participants irrespective of age, sex, race, ethnicity, or education. Typical descriptions were characterized by an average of 23 content units (SD=5) conveyed with 167 syllables (SD=79). The new naming stimuli were recognized by 100% of participants from many countries as being familiar and identifiable, and names provided in response to the task were highly convergent. The majority of stroke health care providers preferred both the precarious painter and naming stimuli. CONCLUSIONS: The description of the new National Institutes of Health Stroke Scale picture, the precarious painter, results in rich samples among healthy speakers that will provide an appropriate basis for the detection of language deficits.
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Etnicidad , Accidente Cerebrovascular , Humanos , Australia , Canadá , Escolaridad , Accidente Cerebrovascular/diagnósticoRESUMEN
BACKGROUND: Recent large core trials have highlighted the effectiveness of mechanical thrombectomy (MT) in acute ischemic stroke with large vessel occlusion. Variable perfusion-imaging thresholds and poor Alberta Stroke Program Early Computed Tomography Score reliability underline the need for more standardized, quantitative ischemia measures for MT patient selection. We aimed to identify the computed tomography perfusion parameter most strongly associated with poor outcomes in patients with acute ischemic stroke-large vessel occlusion with significant ischemic cores. METHODS: In this study from 2 comprehensive stroke centers from 2 comprehensive stroke centers within the Johns Hopkins Medical Enterprise (Johns Hopkins Hospita-East Baltimore and Bayview Medical Campus) from July 29, 2019 to January 29, 2023 in a continuously maintained database, we included patients with acute ischemic stroke-large vessel occlusion with ischemic core volumes defined as relative cerebral blood flow <30% and ≥50 mL on computed tomography perfusion or Alberta Stroke Program Early Computed Tomography Score <6. We used receiver operating characteristics to find the optimal cutoff for parameters like cerebral blood volume (CBV) <34%, 38%, 42%, and relative cerebral blood flow >20%, 30%, 34%, 38%, and time-to-maximum >4, 6, 8, and 10 seconds. The primary outcome was unfavorable outcomes (90-day modified Rankin Scale score 4-6). Multivariable models were adjusted for age, sex, diabetes, baseline National Institutes of Health Stroke Scale, intravenous thrombolysis, and MT. RESULTS: We identified 59 patients with large ischemic cores. A receiver operating characteristic curve analysis showed that CBV<42% ≥68 mL is associated with unfavorable outcomes (90-day modified Rankin Scale score 4-6) with an area under the curve of 0.90 (95% CI, 0.82-0.99) in the total and MT-only cohorts. Dichotomizing at this CBV threshold, patients in the ≥68 mL group exhibited significantly higher relative cerebral blood flow, time-to-maximum >8 and 10 seconds volumes, higher CBV volumes, higher HIR, and lower CBV index. The multivariable model incorporating CBV<42% ≥68 mL predicted poor outcomes robustly in both cohorts (area under the curve for MT-only subgroup was 0.87 [95% CI, 0.75-1.00]). CONCLUSIONS: CBV<42% ≥68 mL most effectively forecasts poor outcomes in patients with large-core stroke, confirming its value alongside other parameters like time-to-maximum in managing acute ischemic stroke-large vessel occlusion.
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PURPOSE: Quantitative mapping of brain perfusion, diffusion, T2 *, and T1 has important applications in cerebrovascular diseases. At present, these sequences are performed separately. This study aims to develop a novel MRI technique to simultaneously estimate these parameters. METHODS: This sequence to measure perfusion, diffusion, T2 *, and T1 mapping with magnetic resonance fingerprinting (MRF) was based on a previously reported MRF-arterial spin labeling (ASL) sequence, but the acquisition module was modified to include different TEs and presence/absence of bipolar diffusion-weighting gradients. We compared parameters derived from the proposed method to those derived from reference methods (i.e., separate sequences of MRF-ASL, conventional spin-echo DWI, and T2 * mapping). Test-retest repeatability and initial clinical application in two patients with stroke were evaluated. RESULTS: The scan time of our proposed method was 24% shorter than the sum of the reference methods. Parametric maps obtained from the proposed method revealed excellent image quality. Their quantitative values were strongly correlated with those from reference methods and were generally in agreement with values reported in the literature. Repeatability assessment revealed that ADC, T2 *, T1 , and B1 + estimation was highly reliable, with voxelwise coefficient of variation (CoV) <5%. The CoV for arterial transit time and cerebral blood flow was 16% ± 3% and 25% ± 9%, respectively. The results from the two patients with stroke demonstrated that parametric maps derived from the proposed method can detect both ischemic and hemorrhagic stroke. CONCLUSION: The proposed method is a promising technique for multi-parametric mapping and has potential use in patients with stroke.
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Imagen por Resonancia Magnética , Accidente Cerebrovascular , Humanos , Imagen por Resonancia Magnética/métodos , Encéfalo/diagnóstico por imagen , Encéfalo/irrigación sanguínea , Espectroscopía de Resonancia Magnética , Perfusión , Accidente Cerebrovascular/diagnóstico por imagen , Fantasmas de Imagen , Procesamiento de Imagen Asistido por Computador/métodosRESUMEN
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.
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Afasia , Diabetes Mellitus , Accidente Cerebrovascular , Humanos , Afasia/diagnóstico por imagen , Afasia/etiología , Afasia/terapia , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Accidente Cerebrovascular/patología , Lenguaje , Diabetes Mellitus/patologíaRESUMEN
Behavioral neurology & neuropsychiatry (BNNP) is a field that seeks to understand brain-behavior relationships, including fundamental brain organization principles and the many ways that brain structures and connectivity can be disrupted, leading to abnormalities of behavior, cognition, emotion, perception, and social cognition. In North America, BNNP has existed as an integrated subspecialty through the United Council for Neurologic Subspecialties since 2006. Nonetheless, the number of behavioral neurologists across academic medical centers and community settings is not keeping pace with increasing clinical and research demand. In this commentary, we provide a brief history of BNNP followed by an outline of the current challenges and opportunities for BNNP from the behavioral neurologist's perspective across clinical, research, and educational spheres. We provide a practical guide for promoting BNNP and addressing the shortage of behavioral neurologists to facilitate the continued growth and development of the subspecialty. We also urge a greater commitment to recruit trainees from diverse backgrounds so as to dismantle persistent obstacles that hinder inclusivity in BNNP-efforts that will further enhance the growth and impact of the subspecialty. With rapidly expanding diagnostic and therapeutic approaches across a range of conditions at the intersection of neurology and psychiatry, BNNP is well positioned to attract new trainees and expand its reach across clinical, research, and educational activities.
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Neurología , Humanos , Neurología/tendencias , Neuropsiquiatría/tendenciasRESUMEN
OBJECTIVE: To examine the relation between baseline white matter hyperintensities (WMH) and change in naming, content production, and efficiency after treatment in subacute aphasia. We hypothesized that more severe baseline WMH would result in less improvement with treatment. DESIGN: Retrospective analysis of a cohort from a double-blind randomized controlled trial (RCT). SETTING: Outpatient clinical setting or participant home. PARTICIPANTS: We retrospectively reviewed imaging and behavioral data for 52 participants with subacute aphasia due to left-hemisphere ischemic stroke enrolled in the RCT. RCT inclusion criteria: English proficiency, normal/corrected-to-normal hearing/vision, and no history of neurologic conditions other than the stroke resulting aphasia. One participant with a chronic right-hemisphere lesion was retained as she presented with no residual deficits on neurologic examination. Individuals with scalp sensitivities or on medications that lower seizure threshold or any N-methyl-D-aspartate (NMDA) antagonists were excluded. Of the 52 participants, for this analysis, 2 were excluded for not having a magnetic resonance imaging, and 7 were excluded for not participating in treatment or pre/post assessment for at least 1 outcome, resulting in final sample of 43 participants (20 women sex, M [SD] age=64.4 [11.9] and M [SD] education=14.9 [3.1] years). INTERVENTIONS: Participants received 15 sessions (2-3 times/week) of computerized lexical-semantic (ie, verification) treatment with [sham/active] transcranial direct current stimulation (tDCS). Sessions were approximately 45 minutes each (tDCS for first 20 minutes). MAIN OUTCOME MEASURES: Naming accuracy, content units (CUs, a measure of semantically accurate production), and efficiency (ie, syllables/CU) on a picture description task. RESULTS: Periventricular WMH severity was independently associated with recovery in picture naming for the active tDCS group. Deep WMH severity was associated with recovery for CU production for the sham tDCS group. CONCLUSION: Baseline periventricular and deep WMH, among other factors, may be an important consideration for prognosis and treatment planning, especially when considered in conjunction with tDCS treatment.
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Afasia , Sustancia Blanca , Humanos , Femenino , Afasia/rehabilitación , Afasia/etiología , Masculino , Persona de Mediana Edad , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Estudios Retrospectivos , Anciano , Método Doble Ciego , Imagen por Resonancia Magnética , Rehabilitación de Accidente Cerebrovascular/métodos , Recuperación de la Función , Accidente Cerebrovascular Isquémico/rehabilitación , Accidente Cerebrovascular Isquémico/diagnóstico por imagen , Accidente Cerebrovascular Isquémico/complicacionesRESUMEN
Unilateral spatial neglect (USN) is a common and disabling cognitive consequence of stroke wherein individuals demonstrate decreased response to contralesional information. Here, we provide an updated narrative review of studies that shed light on the neural mechanisms and predictors of recovery of USN. Additionally, we report a rapid review of randomized controlled trials focusing on USN intervention, both nonpharmacological and pharmacological, published in the last 5 years. Randomized controlled trials are reviewed within the context of systematic reviews and meta-analyses of USN interventions published within the same time frame. The quality of randomized controlled trials of treatment is higher compared to quality reported in previous reviews and meta-analyses. However, remaining weaknesses in participant demographic reporting, as well as small, heterogenous samples, render generalizability and cross-study interpretation a challenge. Nevertheless, evidence regarding neural mechanisms underlying USN recovery and regarding the effectiveness of targeted USN interventions is accumulating and strengthening, setting the foundation for future investigations into patient-specific factors that may influence treatment response. We identify gaps and provide suggestions for future USN intervention research.
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Trastornos de la Percepción , Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular , Humanos , Revisiones Sistemáticas como Asunto , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/terapia , Trastornos de la Percepción/etiología , Trastornos de la Percepción/terapia , Lateralidad Funcional/fisiologíaRESUMEN
BACKGROUND: Transcranial direct-current stimulation (tDCS) is a promising adjunct to therapy for chronic aphasia. METHODS: This single-center, randomized, double-blind, sham-controlled efficacy trial tested the hypothesis that anodal tDCS augments language therapy in subacute aphasia. Secondarily, we compared the effect of tDCS on discourse measures and quality of life and compared the effects on naming to previous findings in chronic stroke. Right-handed English speakers with aphasia <3 months after left hemisphere ischemic stroke were included, unless they had prior neurological or psychiatric disease or injury or were taking certain medications (34 excluded; final sample, 58). Participants were randomized 1:1, controlling for age, aphasia type, and severity, to receive 20 minutes of tDCS (1 mA) or sham-tDCS in addition to fifteen 45-minute sessions of naming treatment (plus standard care). The primary outcome variable was change in naming accuracy of untrained pictures pretreatment to 1-week posttreatment. RESULTS: Baseline characteristics were similar between the tDCS (N=30) and sham (N=28) groups: patients were 65 years old, 53% male, and 2 months from stroke onset on average. In intent-to-treat analysis, the adjusted mean change from baseline to 1-week posttreatment in picture naming was 22.3 (95% CI, 13.5-31.2) for tDCS and 18.5 (9.6-27.4) for sham and was not significantly different. Content and efficiency of picture description improved more with tDCS than sham. Groups did not differ in quality of life improvement. No patients were withdrawn due to adverse events. CONCLUSIONS: tDCS did not improve recovery of picture naming but did improve recovery of discourse. Discourse skills are critical to participation. Future research should examine tDCS in a larger sample with richer functional outcomes. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02674490.
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Afasia , Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular , Estimulación Transcraneal de Corriente Directa , Masculino , Humanos , Anciano , Femenino , Calidad de Vida , Afasia/terapia , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/terapia , Método Doble CiegoRESUMEN
STAIR XII (12th Stroke Treatment Academy Industry Roundtable) included a workshop to discuss the priorities for advancements in neuroimaging in the diagnostic workup of acute ischemic stroke. The workshop brought together representatives from academia, industry, and government. The participants identified 10 critical areas of priority for the advancement of acute stroke imaging. These include enhancing imaging capabilities at primary and comprehensive stroke centers, refining the analysis and characterization of clots, establishing imaging criteria that can predict the response to reperfusion, optimizing the Thrombolysis in Cerebral Infarction scale, predicting first-pass reperfusion outcomes, improving imaging techniques post-reperfusion therapy, detecting early ischemia on noncontrast computed tomography, enhancing cone beam computed tomography, advancing mobile stroke units, and leveraging high-resolution vessel wall imaging to gain deeper insights into pathology. Imaging in acute ischemic stroke treatment has advanced significantly, but important challenges remain that need to be addressed. A combined effort from academic investigators, industry, and regulators is needed to improve imaging technologies and, ultimately, patient outcomes.
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Isquemia Encefálica , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Humanos , Isquemia Encefálica/diagnóstico por imagen , Isquemia Encefálica/terapia , Terapia Trombolítica/métodos , Trombectomía/métodos , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/terapia , Neuroimagen , Resultado del TratamientoRESUMEN
Velocity-selective inversion (VSI) based velocity-selective arterial spin labeling (VSASL) has been developed to measure cerebral blood flow (CBF) with low susceptibility to the prolonged arterial transit time and high sensitivity to brain perfusion signal. The purpose of this magnetic resonance imaging study is to evaluate the test-retest reliability of a VSI-prepared 3D VSASL protocol with whole-brain coverage to detect baseline CBF variations among cognitively normal participants in different brain regions. Coefficients of variation (CoV) of both absolute and relative CBF across scans or sessions, subjects, and gray matter regions were calculated, and corresponding intraclass correlation coefficients (ICC) were computed. The higher between-subject CoV of absolute CBF (13.4 ± 2.0%) over within-subject CoV (within-session: 3.8 ± 1.1%; between-session: 4.9 ± 0.9%) yielded moderate to excellent ICC (within-session: 0.88±0.08; between-session: 0.77±0.14) to detect normal variations of individual CBF. The higher between-region CoV of relative CBF (11.4 ± 3.0%) over within-region CoV (within-session: 2.3 ± 0.9%; between-session: 3.3 ± 1.0%) yielded excellent ICC (within-session: 0.92±0.06; between-session: 0.85±0.12) to detect normal variations of regional CBF. Age, blood pressure, end-tidal CO2, and hematocrit partially explained the variability of CBF across subjects. Together these results show excellent test-retest reliability of VSASL to detect both between-subject and between-region variations supporting its clinical utility.
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Arterias , Imagen por Resonancia Magnética , Humanos , Marcadores de Spin , Reproducibilidad de los Resultados , Imagen por Resonancia Magnética/métodos , Circulación Cerebrovascular/fisiologíaRESUMEN
INTRODUCTION: As the population ages, the prevalence of cognitive impairment is expanding. Given the recent pandemic, there is a need for remote testing modalities to assess cognitive deficits in individuals with neurological disorders. Self-administered, remote, tablet-based cognitive assessments would be clinically valuable if they can detect and classify cognitive deficits as effectively as traditional in-person neuropsychological testing. METHODS: We tested whether the Miro application, a tablet-based neurocognitive platform, measured the same cognitive domains as traditional pencil-and-paper neuropsychological tests. Seventy-nine patients were recruited and then randomized to either undergo pencil-and-paper or tablet testing first. Twenty-nine age-matched healthy controls completed the tablet-based assessments. We identified Pearson correlations between Miro tablet-based modules and corresponding neuropsychological tests in patients and compared scores of patients with neurological disorders with those of healthy controls using t tests. RESULTS: Statistically significant Pearson correlations between the neuropsychological tests and their tablet equivalents were found for all domains with moderate (r > 0.3) or strong (r > 0.7) correlations in 16 of 17 tests (p < 0.05). All tablet-based subtests differentiated healthy controls from neurologically impaired patients by t tests except for the spatial span forward and finger tapping modules. Participants reported enjoyment of the tablet-based testing, denied that it provoked anxiety, and noted no preference between modalities. CONCLUSIONS: This tablet-based application was found to be widely acceptable to participants. This study supports the validity of these tablet-based assessments in the differentiation of healthy controls from patients with neurocognitive deficits in a variety of cognitive domains and across multiple neurological disease etiologies.
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Trastornos del Conocimiento , Disfunción Cognitiva , Enfermedades Neurodegenerativas , Accidente Cerebrovascular , Humanos , Trastornos del Conocimiento/diagnóstico , Trastornos del Conocimiento/etiología , Disfunción Cognitiva/diagnóstico , Accidente Cerebrovascular/complicaciones , Pruebas Neuropsicológicas , Enfermedades Neurodegenerativas/diagnóstico , CogniciónRESUMEN
Wernicke's area has been assumed since the 1800s to be the primary region supporting word and sentence comprehension. However, in 2015 and 2019, Mesulam and colleagues raised what they termed the 'Wernicke conundrum', noting widespread variability in the anatomical definition of this area and presenting data from primary progressive aphasia that challenged this classical assumption. To resolve the conundrum, they posited a 'double disconnection' hypothesis: that word and sentence comprehension deficits in stroke-based aphasia result from disconnection of anterior temporal and inferior frontal regions from other parts of the brain due to white matter damage, rather than dysfunction of Wernicke's area itself. To test this hypothesis, we performed lesion-deficit correlations, including connectome-based lesion-symptom mapping, in four large, partially overlapping groups of English-speaking chronic left hemisphere stroke survivors. After removing variance due to object recognition and associative semantic processing, the same middle and posterior temporal lobe regions were implicated in both word comprehension deficits and complex non-canonical sentence comprehension deficits. Connectome lesion-symptom mapping revealed similar temporal-occipital white matter disconnections for impaired word and non-canonical sentence comprehension, including the temporal pole. We found an additional significant temporal-parietal disconnection for non-canonical sentence comprehension deficits, which may indicate a role for phonological working memory in processing complex syntax, but no significant frontal disconnections. Moreover, damage to these middle-posterior temporal lobe regions was associated with both word and non-canonical sentence comprehension deficits even when accounting for variance due to the strongest anterior temporal and inferior frontal white matter disconnections, respectively. Our results largely agree with the classical notion that Wernicke's area, defined here as middle superior temporal gyrus and middle-posterior superior temporal sulcus, supports both word and sentence comprehension, suggest a supporting role for temporal pole in both word and sentence comprehension, and speak against the hypothesis that comprehension deficits in Wernicke's aphasia result from double disconnection.
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Afasia , Conectoma , Accidente Cerebrovascular , Humanos , Afasia de Wernicke , Comprensión , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/diagnóstico por imagen , Mapeo Encefálico , Imagen por Resonancia MagnéticaRESUMEN
OBJECTIVES: Generalization (or near-transfer) effects of an intervention to tasks not explicitly trained are the most desirable intervention outcomes. However, they are rarely reported and even more rarely explained. One hypothesis for generalization effects is that the tasks improved share the same brain function/computation with the intervention task. We tested this hypothesis in this study of transcranial direct current stimulation (tDCS) over the left inferior frontal gyrus (IFG) that is claimed to be involved in selective semantic retrieval of information from the temporal lobes. MATERIALS AND METHODS: In this study, we examined whether tDCS over the left IFG in a group of patients with primary progressive aphasia (PPA), paired with a lexical/semantic retrieval intervention (oral and written naming), may specifically improve semantic fluency, a nontrained near-transfer task that relies on selective semantic retrieval, in patients with PPA. RESULTS: Semantic fluency improved significantly more in the active tDCS than in the sham tDCS condition immediately after and two weeks after treatment. This improvement was marginally significant two months after treatment. We also found that the active tDCS effect was specific to tasks that require this IFG computation (selective semantic retrieval) but not to other tasks that may require different computations of the frontal lobes. CONCLUSIONS: We provided interventional evidence that the left IFG is critical for selective semantic retrieval, and tDCS over the left IFG may have a near-transfer effect on tasks that depend on the same computation, even if they are not specifically trained. CLINICAL TRIAL REGISTRATION: The Clinicaltrials.gov registration number for the study is NCT02606422.
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Afasia Progresiva Primaria , Estimulación Transcraneal de Corriente Directa , Humanos , Corteza Prefrontal , Semántica , Lóbulo Temporal , Afasia Progresiva Primaria/diagnóstico por imagen , Afasia Progresiva Primaria/terapiaRESUMEN
TRIAL DESIGN: Current protocols for treatment of acute ischemic stroke with intravenous thrombolytics, such as alteplase (tPA) and tenecteplase (tNK), recommend the completion of a routine non-contrast head CT at 24 hours post treatment to evaluate for hemorrhage prior to the initiation of antiplatelet therapy for secondary stroke prevention. This guideline was instituted because it had been part of the protocol in the NINDS multicenter randomized placebo-controlled trial that showed the benefit of IV thrombolytics within 3 hours of stroke onset. Recent observational studies indicate that the repeat (stability) head CT rarely alters clinical management, in the absence of neurological worsening or evidence of clinical signs of hemorrhagic conversion, such as seizures, severe headache, or novel acute deficits. A solitary CT carries with it a non-negligible dose of radiation with additive cost to the medical system at large. METHODS: We aimed to identify, with a randomized, blinded outcome assessment trial, if a routine head CT at 24 hours, in the absence of clinical indication, negatively influences clinical outcomes. We enrolled 58 patients, and evaluated differences between groups with t-tests. We also evaluated differences between outcomes (90 day modified Rankin Scale, mRS and change in National Institutes of Health Stroke Scale, NIHSS) from pretreatment to discharge using multivariable logistic regression, including age, baseline NIHSS, and group as independent variables. RESULTS: We found no added benefit of routine CT on either outcome measure. CONCLUSION: It is likely safe to forgo follow up imaging after thrombolysis in the absence of clinical decompensation.
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Isquemia Encefálica , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Humanos , Estudios de Seguimiento , Accidente Cerebrovascular Isquémico/tratamiento farmacológico , Terapia Trombolítica/efectos adversos , Terapia Trombolítica/métodos , Resultado del Tratamiento , Activador de Tejido Plasminógeno , Fibrinolíticos , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/tratamiento farmacológico , Isquemia Encefálica/diagnóstico por imagen , Isquemia Encefálica/tratamiento farmacológico , Isquemia Encefálica/complicacionesRESUMEN
BACKGROUND: Perfusion and structural imaging play an important role in ischemic stroke. Magnetic resonance fingerprinting (MRF) arterial spin labeling (ASL) is a novel noninvasive method of ASL perfusion that allows simultaneous estimation of cerebral blood flow (CBF), bolus arrival time (BAT), and tissue T1 map in a single scan of <4 minutes. Here, we evaluated the utility of MRF-ASL in patients with ischemic stroke in terms of detecting hemodynamic and structural damage and predicting neurological deficits and disability. METHODS: A total of 34 patients were scanned on 3T magnetic resonance imaging. MRF-ASL, standard single-delay pseudo-continuous ASL, T2-weighted, and diffusion magnetic resonance imaging were performed. Regions of interest of lesion and contralateral normal tissues were manually delineated. CBF (with 2 different compartmental models), BAT, and tissue T1 parameters were quantified. Cross-sectional linear regression analyses were performed to examine the relationship between MRF-ASL parameters and National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale. Receiver operating characteristic analyses were performed to determine the utility of MRF-ASL in the classification of stroke lesion voxels. RESULTS: MRF-ASL derived parameters revealed a significant difference between stroke lesion and contralateral normal regions of interest, in that lesion regions manifested a lower CBF1-compartment (P<0.001), lower CBF2-compartment (P<0.001), longer BAT (P=0.002), and longer T1 (P<0.001) compared with normal regions of interest. NIHSS scores at acute stage revealed a strong association with lesion-normal differences in CBF1-compartment,diff (ß=-0.11, P=0.008), CBF2-compartment,diff (ß=-0.16, P=0.003), and T1,diff (ß=0.008, P=0.001). MRF-ASL parameters were also predictive of NIHSS score and modified Rankin Scale scale measured at a later stage, although the degree of the associations was weaker. These associations tended to be even stronger when the MRF-ASL data were acquired at the acute/subacute stage. Compared with standard pseudo-continuous ASL, the multiparametric capability of MRF-ASL yielded higher area under curve values in the receiver operating characteristic analyses of stroke voxel classifications. CONCLUSIONS: MRF-ASL may provide a new approach for quantitative hemodynamic and structural imaging in ischemic stroke.
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Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Circulación Cerebrovascular/fisiología , Estudios Transversales , Hemodinámica , Humanos , Imagen por Resonancia Magnética/métodos , Espectroscopía de Resonancia Magnética , Marcadores de Spin , Accidente Cerebrovascular/diagnóstico por imagenRESUMEN
PURPOSE OF REVIEW: Stroke is a common cause of disability in aging adults. A given individual's needs after stroke vary as a function of the stroke extent and location. The purpose of this review was to discuss recent clinical investigations addressing rehabilitation of an array of overlapping functional domains. RECENT FINDINGS: Research is ongoing in the domains of movement, cognition, attention, speech, language, swallowing, and mental health. To best assist patients' recovery, innovative research has sought to develop and evaluate behavioral approaches, identify and refine synergistic approaches that augment the response to behavioral therapy, and integrate technology where appropriate, particularly to introduce and titrate real-world complexity and improve the overall experience of therapy. Recent and ongoing trials have increasingly adopted a multidisciplinary nature - augmenting refined behavioral therapy approaches with methods for increasing their potency, such as pharmaceutical or electrical interventions. The integration of virtual reality, robotics, and other technological advancements has generated immense excitement, but has not resulted in consistent improvements over more universally accessible, lower technology therapy.
Asunto(s)
Robótica , Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular , Adulto , Humanos , Accidente Cerebrovascular/terapia , Robótica/métodos , Cognición , Habla , Rehabilitación de Accidente Cerebrovascular/métodos , Recuperación de la FunciónRESUMEN
People with aphasia demonstrate impaired production of bound inflectional morphemes, such as noun plurals and possession. They often show greater difficulty in marking possession versus plurality. Using a new tool for eliciting language, the Morphosyntactic Generation test, we assessed people with primary progressive aphasia and those in the acute and chronic phase following left hemisphere stroke. Clinical profiles were associated with different strengths and weaknesses in language production. Performance of the plural was stronger than possessive in group analyses. However, some individuals demonstrated the inverse pattern of performance. These participants provide counter-evidence to the theory that difficulty with marking possessives is purely the result of their greater cognitive-linguistic complexity and support a functional double dissociation between possessives and plurals. The deficits resulted from morphosyntactic impairment. Future work is needed to understand why plural and possessive markers were differently sensitive to neurological disorders of language.
Asunto(s)
Afasia Progresiva Primaria/fisiopatología , Afasia Progresiva Primaria/psicología , Lingüística , Anciano , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
PURPOSE: We aimed to investigate: (1) the clinical, diagnostic value of a written discourse task, and (2) the relationship between executive functions and written discourse within the spectrum of individuals with mild cognitive impairment (MCI). METHOD: To determine whether written discourse performance predicts clinical course among individuals with MCI, we retrospectively classified individuals with MCI as converters (N = 26) who were later diagnosed with dementia or as a stable MCI group (N = 45). We quantified core word measures from written discourse samples obtained from the Cookie Theft picture description task. RESULT: Written discourse measures differentiated converters from the stable MCI group. Converters produced a fewer number of core words than the stable MCI group. A measure of executive function significantly predicted performance on the production of core words in written discourse for the converters. In a multivariable regression, production of core words remained the only explanatory variable closely associated with the progression to dementia in MCI. CONCLUSION: Written discourse tasks can predict the likelihood of MCI progressing to dementia, independently of recall and an executive function measure. Correlational results suggest that written discourse performance was associated with executive function as measured by the Trail Making Test. Our findings emphasize the usefulness of including written discourse tasks in language assessment batteries targeting preclinical dementia populations.