The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform
Edward F Chang - One of the best experts on this subject based on the ideXlab platform.
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data driven visual framework for the characterization of Aphasias across stroke post resective and neurodegenerative disorders over time
Frontiers in Neurology, 2020Co-Authors: Joline M Fan, Mitchel S Berger, Maria Luisa Gornotempini, Nina F Dronkers, Bruce L Miller, Edward F ChangAbstract:Aphasia classifications and specialized language batteries differ across the fields of neurodegenerative disorders and lesional brain injuries, resulting in difficult comparisons of language deficits across etiologies. In this study, we present a simplified framework, in which a widely-used aphasia battery captures clinical clusters across disease etiologies and provides a quantitative and visual method to characterize and track patients over time. The framework is used to evaluate populations representing three disease etiologies: stroke, primary progressive aphasia (PPA), and post-operative aphasia. A total of 330 patients across three populations with cerebral injury leading to aphasia were investigated, including 76 patients with stroke, 107 patients meeting criteria for PPA, and 147 patients following left hemispheric resective surgery. Western Aphasia Battery (WAB) measures (Information Content, Fluency, answering Yes/No questions, Auditory Word Recognition, Sequential Commands, and Repetition) were collected across the three populations and analyzed to develop a multi-dimensional aphasia model using dimensionality reduction techniques. Two orthogonal dimensions were found to explain 87% of the variance across aphasia phenotypes and three disease etiologies. The first dimension reflects shared weighting across aphasia subscores and correlated with aphasia severity. The second dimension incorporates fluency and comprehension, thereby separating Wernicke's from Broca's aphasia, and the non-fluent/agrammatic from semantic PPA variants. Clusters representing clinical classifications, including late PPA presentations, were preserved within the two-dimensional space. Early PPA presentations were not classifiable, as specialized batteries are needed for phenotyping. Longitudinal data was further used to visualize the trajectory of Aphasias during recovery or disease progression, including the rapid recovery of post-operative aphasic patients. This method has implications for the conceptualization of aphasia as a spectrum disorder across different disease etiology and may serve as a framework to track the trajectories of aphasia progression and recovery.
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transient Aphasias after left hemisphere resective surgery
Journal of Neurosurgery, 2015Co-Authors: Stephen M Wilson, Daniel Lam, Miranda Babiak, David W Perry, Tina Shih, Christopher P Hess, Mitchel S Berger, Edward F ChangAbstract:OBJECT Transient Aphasias are often observed in the first few days after a patient has undergone resection in the language-dominant hemisphere. The aims of this prospective study were to characterize the incidence and nature of these Aphasias and to determine whether there are relationships between location of the surgical site and deficits in specific language domains. METHODS One hundred ten patients undergoing resection to the language-dominant hemisphere participated in the study. Language was evaluated prior to surgery and 2–3 days and 1 month postsurgery using the Western Aphasia Battery and the Boston Naming Test. Voxel-based lesion-symptom mapping was used to identify relationships between the surgical site location assessed on MRI and deficits in fluency, information content, comprehension, repetition, and naming. RESULTS Seventy-one percent of patients were classified as aphasic based on the Western Aphasia Battery 2–3 days postsurgery, with deficits observed in each of the language domains exam...
Jason D Warren - One of the best experts on this subject based on the ideXlab platform.
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Non-verbal sound processing in the primary progressive Aphasias
Brain, 2010Co-Authors: Johanna C. Goll, Jenny H.y. Loo, Doris-eva Bamiou, Sebastian J. Crutch, Chris Frost, Jonathan D Rohrer, Jason D WarrenAbstract:Little is known about the processing of non-verbal sounds in the primary progressive Aphasias. Here, we investigated the processing of complex non-verbal sounds in detail, in a consecutive series of 20 patients with primary progressive aphasia [12 with progressive non-fluent aphasia; eight with semantic dementia]. We designed a novel experimental neuropsychological battery to probe complex sound processing at early perceptual, apperceptive and semantic levels, using within-modality response procedures that minimized other cognitive demands and matching tests in the visual modality. Patients with primary progressive aphasia had deficits of non-verbal sound analysis compared with healthy age-matched individuals. Deficits of auditory early perceptual analysis were more common in progressive non-fluent aphasia, deficits of apperceptive processing occurred in both progressive non-fluent aphasia and semantic dementia, and deficits of semantic processing also occurred in both syndromes, but were relatively modality specific in progressive non-fluent aphasia and part of a more severe generic semantic deficit in semantic dementia. Patients with progressive non-fluent aphasia were more likely to show severe auditory than visual deficits as compared to patients with semantic dementia. These findings argue for the existence of core disorders of complex non-verbal sound perception and recognition in primary progressive aphasia and specific disorders at perceptual and semantic levels of cortical auditory processing in progressive non-fluent aphasia and semantic dementia, respectively.
Wan Xua - One of the best experts on this subject based on the ideXlab platform.
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Study on characteristics and rehabilitation mechanism of subcortex aphasia
Guangdong Medical Journal, 2009Co-Authors: Wan XuaAbstract:Objective To analyze the characteristics of subcortex aphasia and to study its rehabilitation mechanism.Methods Seventy subcortex aphasics were evaluated by Chinese Rehabilitation Reserch Center Aphasia Examination (CRRCAE) before and after 4 weeks of rehabilitation therapy. The characteristics of subcortex aphasia was analyzed before treatment,and rehabilitation mechanism was examined before and after treatment. Results For subcortex aphasics,the ture answer rate was above 60% on vocabulary level of listening apprehension,re-stating and reading apprehension. After language rehabilitation therapy,language ability improved at deferent levels,especially on vocabulary and sentence level of listening apprehension,speaking and re-stating,and also on reading and executing character order. The true answer rate had significant differences between two evaluations(P0.05). Conclusion The listening apprehension and re-stating abilities of subcortex aphasics are relatively preserved and all the language abilities can be improved by language rehabilitation therapy.
Johanna C. Goll - One of the best experts on this subject based on the ideXlab platform.
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Non-verbal sound processing in the primary progressive Aphasias
Brain, 2010Co-Authors: Johanna C. Goll, Jenny H.y. Loo, Doris-eva Bamiou, Sebastian J. Crutch, Chris Frost, Jonathan D Rohrer, Jason D WarrenAbstract:Little is known about the processing of non-verbal sounds in the primary progressive Aphasias. Here, we investigated the processing of complex non-verbal sounds in detail, in a consecutive series of 20 patients with primary progressive aphasia [12 with progressive non-fluent aphasia; eight with semantic dementia]. We designed a novel experimental neuropsychological battery to probe complex sound processing at early perceptual, apperceptive and semantic levels, using within-modality response procedures that minimized other cognitive demands and matching tests in the visual modality. Patients with primary progressive aphasia had deficits of non-verbal sound analysis compared with healthy age-matched individuals. Deficits of auditory early perceptual analysis were more common in progressive non-fluent aphasia, deficits of apperceptive processing occurred in both progressive non-fluent aphasia and semantic dementia, and deficits of semantic processing also occurred in both syndromes, but were relatively modality specific in progressive non-fluent aphasia and part of a more severe generic semantic deficit in semantic dementia. Patients with progressive non-fluent aphasia were more likely to show severe auditory than visual deficits as compared to patients with semantic dementia. These findings argue for the existence of core disorders of complex non-verbal sound perception and recognition in primary progressive aphasia and specific disorders at perceptual and semantic levels of cortical auditory processing in progressive non-fluent aphasia and semantic dementia, respectively.
Thomas E Cope - One of the best experts on this subject based on the ideXlab platform.
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artificial grammar learning in vascular and progressive non fluent Aphasias
Neuropsychologia, 2017Co-Authors: Thomas E Cope, Benjamin Wilson, Holly Robson, Rebecca Drinkall, Lauren R Dean, Manon Grube, Simon P Jones, Karalyn Patterson, Timothy D GriffithsAbstract:Patients with non-fluent Aphasias display impairments of expressive and receptive grammar. This has been attributed to deficits in processing configurational and hierarchical sequencing relationships. This hypothesis had not been formally tested. It was also controversial whether impairments are specific to language, or reflect domain general deficits in processing structured auditory sequences. Here we used an artificial grammar learning paradigm to compare the abilities of controls to participants with agrammatic aphasia of two different aetiologies: stroke and frontotemporal dementia. Ten patients with non-fluent variant primary progressive aphasia (nfvPPA), 12 with non-fluent aphasia due to stroke, and 11 controls implicitly learned a novel mixed-complexity artificial grammar designed to assess processing of increasingly complex sequencing relationships. We compared response profiles for otherwise identical sequences of speech tokens (nonsense words) and tone sweeps. In all three groups the ability to detect grammatical violations varied with sequence complexity, with performance improving over time and being better for adjacent than non-adjacent relationships. Patients performed less well than controls overall, and this was related more strongly to aphasia severity than to aetiology. All groups improved with practice and performed well at a control task of detecting oddball nonwords. Crucially, group differences did not interact with sequence complexity, demonstrating that aphasic patients were not disproportionately impaired on complex structures. Hierarchical cluster analysis revealed that response patterns were very similar across all three groups, but very different between the nonsense word and tone tasks, despite identical artificial grammar structures. Overall, we demonstrate that agrammatic aphasics of two different aetiologies are not disproportionately impaired on complex sequencing relationships, and that the learning of phonological and non-linguistic sequences occurs independently. The similarity of profiles of discriminatory abilities and rule learning across groups suggests that insights from previous studies of implicit sequence learning in vascular aphasia are likely to prove applicable in nfvPPA.