Nervous System Commons^™

Partial Least Squares Multimodal Analysis Of Brain Network Correlates Of Language Deficits In Aphasia, Sigfus Kristinsson, Dirk B. Den Ouden, Chris Rorden, Roger Newman-Norlund, Lisa Johnson, Janina Wilmskoetter, Ezequiel Gleichgerrcht, Argye E. Hillis, Gregory Hickok, Julius Fridriksson, Leonardo Bonilha

Communication Sciences and Disorders Faculty Articles and Research

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Lesion-symptom mapping techniques are essential to determine brain regions critical for language functions. However, high collinearity in neuroimaging and behavioural data remains a challenge for distinguishing neural substrates supporting multiple language domains (shared variance) and those subserving specific language functions (unique variance). Here, we employed a novel approach to multimodal lesion-symptom mapping using multivariate partial least squares regression to delineate the latent structure of lesion-behavioural mapping in aphasia and decompose the shared and unique neural determinants of language impairments. A total of 86 participants with chronic (>12-month post-stroke) aphasia after left hemisphere strokes were examined. Language impairment was assessed …

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Benchmarking Machine Learning Models In Lesion-Symptom Mapping For Predicting Language Outcomes In Stroke Survivors, Deepa Tilwani, Christian O'Reilly, Nicholas Riccardi, Valerie L. Shalin, Dirk B. Den Ouden, Julius Fridriksson, Svetlana V. Shinkareva, Amit P. Sheth, Rutvik H. Desai

Communication Sciences and Disorders Faculty Articles and Research

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Several decades of research have investigated the neural connections between stroke-induced brain damage and language difficulties. Typically, lesion-symptom mapping (LSM) studies that address this connection have relied on mass univariate statistics, which do not account for multidimensional relationships between variables. Machine learning (ML) techniques, which can capture these intricate connections, offer a promising complement to LSM methods. To test this promise, we benchmarked ML models on structural and functional MRI to predict aphasia severity (N = 238) and naming impairment (N = 191) for a cohort of chronic-stage stroke survivors. We used nested cross-validation to examine performance along …

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Verbal Working Memory And Syntactic Comprehension Segregate Into The Dorsal And Ventral Streams, Respectively, William Matchin, Zeinab K. Mollasaraei, Leonardo Bonilha, Christopher Rorden, Gregory Hickok, Dirk B. Den Ouden, Julius Fridriksson

Communication Sciences and Disorders Faculty Articles and Research

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Syntactic processing and verbal working memory are both essential components to sentence comprehension. Nonetheless, the separability of these systems in the brain remains unclear. To address this issue, we performed causal-inference analyses based on lesion and connectome network mapping using MRI and behavioural testing in two groups of individuals with chronic post-stroke aphasia. We employed a rhyme judgement task with heavy working memory load without articulatory confounds, controlling for the overall ability to match auditory words to pictures and to perform a metalinguistic rhyme judgement, isolating the effect of working memory load (103 individuals). We assessed non-canonical sentence comprehension, isolating …

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A Rose By Any Other Name: Mapping Taxonomic And Thematic Naming Errors Poststroke, Nicholas Riccardi, Deena Schwen Blackett, Abigail Broadhead, Dirk B. Den Ouden, Chris Rorden, Julius Fridriksson, Leonardo Bonilha, Rutvik H. Desai

Communication Sciences and Disorders Faculty Articles and Research

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Understanding the neurobiology of semantic knowledge is a major goal of cognitive neuroscience. Taxonomic and thematic semantic knowledge are represented differently within the brain's conceptual networks, but the specific neural mechanisms remain unclear. Some neurobiological models propose that the anterior temporal lobe is an important hub for taxonomic knowledge, whereas the TPJ is especially involved in the representation of thematic knowledge. However, recent studies have provided divergent evidence. In this context, we investigated the neural correlates of taxonomic and thematic confrontation naming errors in 79 people with aphasia. We used three complementary lesion-symptom mapping (LSM) methods to investigate how structure …

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The Aphasia Recovery Cohort, An Open-Source Chronic Stroke Repository, Makayla Gibson, Roger Newman-Norlund, Leonardo Bonilha, Julius Fridriksson, Gregory Hickok, Argye E. Hillis, Dirk B. Den Ouden, Chris Rorden

Communication Sciences and Disorders Faculty Articles and Research

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Sharing neuroimaging datasets enables reproducibility, education, tool development, and new discoveries. Neuroimaging from many studies are publicly available, providing a glimpse into progressive disorders and human development. In contrast, few stroke studies are shared, and these datasets lack longitudinal sampling of functional imaging, diffusion imaging, as well as the behavioral and demographic data that encourage novel applications. This is surprising, as stroke is a leading cause of disability, and acquiring brain imaging is considered standard of care. The first release of the Aphasia Recovery Cohort includes imaging data, demographics and behavioral measures from 230 chronic stroke survivors who experienced aphasia. …

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Dissociating Reading And Auditory Comprehension In Persons With Aphasia, Rachael M. Harrington, Sigfus Kristinsson, Janina Wilmskoetter, Natalie Busby, Dirk B. Den Ouden, Chris Rorden, Julius Fridriksson, Leonardo Bonilha

Communication Sciences and Disorders Faculty Articles and Research

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Language comprehension is often affected in individuals with post-stroke aphasia. However, deficits in auditory comprehension are not fully correlated with deficits in reading comprehension and the mechanisms underlying this dissociation remain unclear. This distinction is important for understanding language mechanisms, predicting long-term impairments and future development of treatment interventions. Using comprehensive auditory and reading measures from a large cohort of individuals with aphasia, we evaluated the relationship between aphasia type and reading comprehension impairments, the relationship between auditory versus reading comprehension deficits and the crucial neuroanatomy supporting the dissociation between post-stroke reading and auditory deficits. Scores from the Western Aphasia …

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Lower Socioeconomic Status Is Associated With Premature Brain Aging, Natalie Busby, Sarah Newman-Norlund, Sara Sayers, Roger Newman-Norlund, Janina Wilmskoetter, Chris Rorden, Samaneh Nemati, Sarah Wilson, Nicholas Riccardi, Rebecca Roth, Lisa Johnson, Dirk B. Den Ouden, Julius Fridriksson, Leonardo Bonilha

Communication Sciences and Disorders Faculty Articles and Research

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Background

Premature age-related brain changes may be influenced by physical health factors. Lower socioeconomic status (SES) is often associated with poorer physical health. In this study, we aimed to investigate the relationship between SES and premature brain aging.

Methods

Brain age was estimated from T1-weighted images using BrainAgeR in 217 participants from the ABC@UofSC Repository. The difference between brain and chronological age (BrainGAP) was calculated. Multiple regression models were used to predict BrainGAP with age, SES, body mass index, diabetes, hypertension, sex, race, and education as predictors. SES was calculated from size-adjusted household income and the cost of living. …

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Digital 3d Brain Mri Arterial Territories Atlas, Chin-Fu Liu, Johnny Hsu, Xin Xu, Ganghyun Kim, Shannon M. Sheppard, Erin L. Meier, Michael I. Miller, Argye E. Hillis, Andreia V. Faria

Communication Sciences and Disorders Faculty Articles and Research

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The locus and extent of brain damage in the event of vascular insult can be quantitatively established quickly and easily with vascular atlases. Although highly anticipated by clinicians and clinical researchers, no digital MRI arterial atlas is readily available for automated data analyses. We created a digital arterial territory atlas based on lesion distributions in 1,298 patients with acute stroke. The lesions were manually traced in the diffusion-weighted MRIs, binary stroke masks were mapped to a common space, probability maps of lesions were generated and the boundaries for each arterial territory was defined based on the ratio between probabilistic maps. …

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Brain Age Predicts Long-Term Recovery In Post-Stroke Aphasia, Sigfus Kristinsson, Natalie Busby, Christopher Rorden, Roger Newman-Norlund, Dirk B. Den Ouden, Sigridur Magnusdottir, Haukur Hjaltason, Helga Thors, Argye E. Hillis, Olafur Kjartansson, Leonardo Bonilha, Julius Fridriksson

Communication Sciences and Disorders Faculty Articles and Research

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The association between age and language recovery in stroke remains unclear. Here, we used neuroimaging data to estimate brain age, a measure of structural integrity, and examined the extent to which brain age at stroke onset is associated with (i) cross-sectional language performance, and (ii) longitudinal recovery of language function, beyond chronological age alone. A total of 49 participants (age: 65.2 ± 12.2 years, 25 female) underwent routine clinical neuroimaging (T1) and a bedside evaluation of language performance (Bedside Evaluation Screening Test-2) at onset of left hemisphere stroke. Brain age was estimated from enantiomorphically reconstructed brain scans using a machine …

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Functional Differentiation In The Language Network Revealed By Lesion-Dymptom Mapping, William Matchin, Alexandra Basilakos, Dirk B. Den Ouden, Brielle C. Stark, Gregory Hickok, Julius Fridriksson

Communication Sciences and Disorders Faculty Articles and Research

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Theories of language organization in the brain commonly posit that different regions underlie distinct linguistic mechanisms. However, such theories have been criticized on the grounds that many neuroimaging studies of language processing find similar effects across regions. Moreover, condition by region interaction effects, which provide the strongest evidence of functional differentiation between regions, have rarely been offered in support of these theories. Here we address this by using lesion-symptom mapping in three large, partially-overlapping groups of aphasia patients with left hemisphere brain damage due to stroke (N = 121, N = 92, N = 218). We identified multiple measure by …

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Agrammatism And Paragrammatism: A Cortical Double Dissociation Revealed By Lesion-Symptom Mapping, William Matchin, Alexandra Basilakos, Brielle C. Stark, Dirk B. Den Ouden, Fridolin Gross, Gregory Hickok

Communication Sciences and Disorders Faculty Articles and Research

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The fundamental distinction of grammatical deficits in aphasia, agrammatism and paragrammatism, was made over a century ago. However, the extent to which the agrammatism/paragrammatism distinction exists independently of differences in speech fluency has not clearly been investigated. Despite much research on agrammatism, the lesion correlates of paragrammatism are essentially unknown. Lesion-symptom mapping was used to investigate the degree to which the lesion correlates of agrammatism and paragrammatism overlap or dissociate. Four expert raters assessed videos of 53 right-handed patients with aphasia following chronic left-hemisphere stroke retelling the Cinderella story. Consensus discussion determined each subject’s classification with respect to grammatical deficits …

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Behavioral And Neural Correlates Of Normal Aging Effects On Motor Preparatory Mechanisms Of Speech Production And Limb Movement, Karim Johari, Dirk B. Den Ouden, Roozbeh Behroozmand

Communication Sciences and Disorders Faculty Articles and Research

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Normal aging is associated with decline of the sensorimotor mechanisms that support movement function in the human brain. In this study, we used behavioral and event-related potential (ERP) recordings to investigate the effects of normal aging on the motor preparatory mechanisms of speech production and limb movement. The experiment involved two groups of older and younger adults who performed randomized speech vowel vocalization and button press motor reaction time tasks in response to temporally predictable and unpredictable visual stimuli. Behavioral results revealed age-related slowness of motor reaction time only during speech production in response to temporally unpredictable stimuli, and this …

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Revealing The Dual Streams Of Speech Processing, Julius Fridriksson, Grigori Yourganov, Leonardo Bonilha, Alexandra Basilakos, Dirk B. Den Ouden, Chris Rorden

Communication Sciences and Disorders Faculty Articles and Research

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Several dual route models of human speech processing have been proposed suggesting a large-scale anatomical division between cortical regions that support motor–phonological aspects vs. lexical–semantic aspects of speech processing. However, to date, there is no complete agreement on what areas subserve each route or the nature of interactions across these routes that enables human speech processing. Relying on an extensive behavioral and neuroimaging assessment of a large sample of stroke survivors, we used a data-driven approach using principal components analysis of lesion-symptom mapping to identify brain regions crucial for performance on clusters of behavioral tasks without a priori separation into …

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Different Neural Mechanisms For Causal Processing In Language And Perception: An Fmri Study, Brett B. Bankson, Dirk B. Den Ouden

Communication Sciences and Disorders Faculty Articles and Research

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Information that is used to establish and evaluate causal relationships between objects and events can be gleaned from many sources, especially those that rely on language and perception. For example, sentences with a verb structure using change of state verbs such as “to break” or “to freeze” imply sequential events that express understood causal relationships. At this time, little research has examined the neural correlates of causal verb processing or has compared them to the more well researched brain activity involved in perceptual causal processing. This study investigated the extent to which the evaluation of causal verbs and causal image …

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High Definition Transcranial Direct Current Stimulation Als Mogelijke Hulp Bij Afasie-Herstel, Dirk B. Den Ouden

Communication Sciences and Disorders Faculty Articles and Research

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Samenvatting

Nieuwe kennis over het plastische vermogen van het volwassen brein, ook na hersenschade, heeft geleid tot hernieuwde interesse in technieken om deze plasticiteit fysiek te sturen. Een van die technieken is transcranial Direct Current Stimulation (tDCS), waarmee de exciteerbaarheid van hersencellen beïnvloed wordt door een zwakke gelijkstroom door de hersenschors te leiden. Als met deze methode hersenplasticiteit bevorderd en gestuurd kan worden, is het wellicht mogelijk om de uitkomsten van afasietherapie te verbeteren, door het aanpakken van de fysieke bron van de stoornis. Dit artikel behandelt kort de geschiedenis en de werking van tDCS, alvorens een overzicht te geven …

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High-Definition Tdcs Of Noun And Verb Retrieval In Naming And Lexical Decision, Svetlana Malyutina, Dirk B. Den Ouden

Communication Sciences and Disorders Faculty Articles and Research

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High-definition transcranial direct current stimulation (HD-tDCS) is a novel brain stimulation method that has high potential for use in language therapy for speakers with aphasia, due to its safety and focality. This study aimed to obtain foundational data on using HD-tDCS to modulate language processing in healthy speakers. Participants received stimulation either of left Broca’s area or of angular gyrus (20 minutes of anodal, cathodal and sham stimulation on separate days), followed by naming and lexical decision tasks with single-word verb and noun stimuli. We found that cathodal stimulation over both Broca’s area and left angular gyrus increased naming speed …

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Training Verb Argument Structure Production In Agrammatic Aphasia: Behavioral And Neural Recovery Patterns, Cynthia K. Thompson, Ellyn A. Riley, Dirk B. Den Ouden, Aya Meltzer-Asscher, Sladjana Lukic

Communication Sciences and Disorders Faculty Articles and Research

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Introduction

Neuroimaging and lesion studies indicate a left hemisphere network for verb and verb argument structure processing, involving both frontal and temporoparietal brain regions. Although their verb comprehension is generally unimpaired, it is well known that individuals with agrammatic aphasia often present with verb production deficits, characterized by an argument structure complexity hierarchy, indicating faulty access to argument structure representations for production and integration into syntactic contexts. Recovery of verb processing in agrammatism, however, has received little attention and no studies have examined the neural mechanisms associated with improved verb and argument structure processing. In the present study we trained …

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The Neural Substrates Of Complex Argument Structure Representations: Processing “Alternating Transitivity” Verbs, Aya Meltzer-Asscher, Julia Schuchard, Dirk B. Den Ouden, Cynthia K. Thompson

Communication Sciences and Disorders Faculty Articles and Research

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This study examines the neural correlates of processing verbal entries with multiple argument structures using functional magnetic resonance imaging (fMRI). We compared brain activation in response to “alternating transitivity” verbs, corresponding to two different verbal alternates—one transitive and one intransitive—and simple verbs, with only one, intransitive, thematic grid. Fourteen young healthy participants performed a lexical decision task with the two verb types. Results showed significantly greater activation in the angular and supramarginal gyri (Brodmann areas (BAs) 39 and 40) extending to the posterior superior and middle temporal gyri bilaterally, for alternating compared to simple verbs. Additional activation was detected in …

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Network Modulation During Complex Syntactic Processing, Dirk B. Den Ouden, Dorothee Saur, Wolfgang Mader, Björn Schelter, Sladjana Lukic, Eisha Wali, Jens Timmer, Cynthia K. Thompson

Communication Sciences and Disorders Faculty Articles and Research

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Complex sentence processing is supported by a left-lateralized neural network including inferior frontal cortex and posterior superior temporal cortex. This study investigates the pattern of connectivity and information flow within this network. We used fMRI BOLD data derived from 12 healthy participants reported in an earlier study (Thompson, C. K., Den Ouden, D. B., Bonakdarpour, B., Garibaldi, K., & Parrish, T. B. (2010b). Neural plasticity and treatment-induced recovery of sentence processing in agrammatism. Neuropsychologia, 48(11), 3211–3227) to identify activation peaks associated with object-cleft over syntactically less complex subject-cleft processing. Directed Partial Correlation Analysis was conducted on time series …

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Neural Plasticity And Treatment-Induced Recovery Of Sentence Processing In Agrammatism, Cynthia K. Thompson, Dirk B. Den Ouden, Borna Bonakdarpour, Kyla Garibaldi, Todd B. Parrish

Communication Sciences and Disorders Faculty Articles and Research

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This study examined patterns of neural activation associated with treatment-induced improvement of complex sentence production (and comprehension) in six individuals with stroke-induced agrammatic aphasia, taking into account possible alterations in blood flow often associated with stroke, including delayed time-to-peak of the hemodynamic response function (HRF) and hypoperfused tissue. Aphasic participants performed an auditory verification fMRI task, processing object cleft, subject cleft, and simple active sentences, prior to and following a course of Treatment of Underlying Forms (TUF; Thompson et al., 2003), a linguistically based approach for treating aphasic sentence deficits, which targeted object relative clause constructions. The patients also were …

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Neuroimaging And Recovery Of Language In Aphasia, Cynthia K. Thompson, Dirk B. Den Ouden

Communication Sciences and Disorders Faculty Articles and Research

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The use of functional neuroimaging techniques has advanced what is known about the neural mechanisms used to support language processing in aphasia resulting from brain damage. This paper highlights recent findings derived from neuroimaging studies focused on neuroplasticity of language networks, the role of the left and right hemispheres in this process, and studies examining how treatment affects the neurobiology of recovery. We point out variability across studies as well as factors related to this variability, and we emphasize challenges that remain for research.

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Argument Structure Effects In Action Verb Naming In Static And Dynamic Conditions, Dirk B. Den Ouden, Steve Fix, Todd B. Parrish, Cynthia K. Thompson

Communication Sciences and Disorders Faculty Articles and Research

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Argument structure, as in the participant roles entailed within the lexical representation of verbs, affects verb processing. Recent neuroimaging studies show that when verbs are heard or read, the posterior temporoparietal region shows increased activation for verbs with greater versus lesser argument structure complexity, usually bilaterally. In addition, patients with agrammatic aphasia show verb production deficits, graded based on argument structure complexity. In the present study, we used fMRI to examine the neural correlates of verb production in overt action naming conditions. In addition, we tested the differential effects of naming when verbs were presented dynamically in video segments versus …

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