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1.
Neuroimage ; 247: 118778, 2022 02 15.
Article in English | MEDLINE | ID: mdl-34896587

ABSTRACT

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 region interaction effects, associating damage to the posterior middle temporal gyrus with syntactic comprehension deficits, damage to posterior inferior frontal gyrus with expressive agrammatism, and damage to inferior angular gyrus with semantic category word fluency deficits. Our results are inconsistent with recent hypotheses that regions of the language network are undifferentiated with respect to high-level linguistic processing.


Subject(s)
Aphasia/physiopathology , Brain Mapping/methods , Brain/physiopathology , Adult , Aged , Comprehension , Female , Humans , Language , Magnetic Resonance Imaging/methods , Male , Middle Aged , Parietal Lobe/physiopathology , Prefrontal Cortex/physiopathology , Stroke/physiopathology , Temporal Lobe
2.
J Speech Lang Hear Res ; 64(11): 4366-4389, 2021 11 08.
Article in English | MEDLINE | ID: mdl-34554878

ABSTRACT

Purpose Spoken discourse analysis is commonly employed in the assessment and treatment of people living with aphasia, yet there is no standardization in assessment, analysis, or reporting procedures, thereby precluding comparison/meta-analyses of data and hindering replication of findings. An important first step is to identify current practices in collecting and analyzing spoken discourse in aphasia. Thus, this study surveyed current practices, with the goal of working toward standardizing spoken discourse assessment first in research settings with subsequent implementation into clinical settings. Method A mixed-methods (quantitative and qualitative) survey was publicized to researchers and clinicians around the globe who have collected and/or analyzed spoken discourse data in aphasia. The survey data were collected between September and November 2019. Results Of the 201 individuals who consented to participate, 189 completed all mandatory questions in the survey (with fewer completing nonmandatory response questions). The majority of respondents reported barriers to utilizing discourse including transcription, coding, and analysis. The most common barrier was time (e.g., lack of time). Respondents also indicated that there was a lack of, and a need for, psychometric properties and normative data for spoken discourse use in the assessment and treatment of persons with aphasia. Quantitative and qualitative results are described in detail. Conclusions The current survey study evaluated spoken discourse methods in aphasia across research and clinical settings. Findings from this study will be used to guide development of process standardization in spoken discourse and for the creation of a psychometric and normative property database. Supplemental Material https://doi.org/10.23641/asha.166395100.


Subject(s)
Aphasia , Aphasia/diagnosis , Humans , Psychometrics , Surveys and Questionnaires
3.
J Speech Lang Hear Res ; 64(10): 4004-4013, 2021 10 04.
Article in English | MEDLINE | ID: mdl-34525306

ABSTRACT

Purpose When we speak, we gesture, and indeed, persons with aphasia gesture more frequently. The reason(s) for this is still being investigated, spurring an increase in the number of studies of gesture in persons with aphasia. As the number of studies increases, so too does the need for a shared set of best practices for gesture research in aphasia. After briefly reviewing the importance and use of gesture in persons with aphasia, this viewpoint puts forth methodological and design considerations when evaluating gesture in persons with aphasia. Method & Results We explore several different design and methodological considerations for gesture research specific to persons with aphasia, such as video angle specifications, data collection techniques, and analysis considerations. The goal of these suggestions is to develop transparent and reproducible methods for evaluating gesture in aphasia to build a solid foundation for continued work in this area. Conclusions We have proposed that it is critical to evaluate multimodal communication in a methodologically robust way to facilitate increased knowledge about the relationship of gesture to spoken language, cognition, and to other aspects of living with aphasia and recovery from aphasia. We conclude by postulating future directions for gesture research in aphasia.


Subject(s)
Aphasia , Gestures , Humans
4.
Neurobiol Lang (Camb) ; 1(2): 208-225, 2020.
Article in English | MEDLINE | ID: mdl-34296193

ABSTRACT

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 as Agrammatic, Paragrammatic, Both, or No Grammatical Deficit. Each subject's lesion was manually drawn on a high-resolution MRI and warped to standard space for group analyses. Lesion-symptom mapping analyses were performed in NiiStat including lesion volume as a covariate. Secondary analyses included speech rate (words per minute) as an additional covariate. Region of interest analyses identified a double dissociation between these syndromes: damage to Broca's area was significantly associated with agrammatism, p = 0.001 (but not paragrammatism, p = 0.930), while damage to the left posterior superior and middle temporal gyri was significantly associated with paragrammatism, p < 0.001 (but not agrammatism, p = 0.873). The same results obtained when regressing out the effect of speech rate, and nonoverlapping lesion distributions between the syndromes were confirmed by uncorrected whole brain analyses. Our results support a fundamental distinction between agrammatism and paragrammatism.

5.
Am J Speech Lang Pathol ; 31(1): 30-47, 2022 01 18.
Article in English | MEDLINE | ID: mdl-34033493

ABSTRACT

PURPOSE: In persons living with aphasia, we will explore the relationship between iconic gesture production during spontaneous speech and discourse task, spoken language, and demographic information. METHOD: Employing the AphasiaBank database, we coded iconic gestures in 75 speakers with aphasia during two spoken discourse tasks: a procedural narrative, which involved participants telling the experimenter how to make a sandwich ("Sandwich"), and a picture sequence narrative, which had participants describe the picture sequence to the experimenter ("Window"). Forty-three produced a gesture during both tasks, and we further evaluate data from this subgroup as a more direct comparison between tasks. RESULTS: More iconic gestures, at a higher rate, were produced during the procedural narrative. For both tasks, there was a relationship between iconic gesture rate, modeled as iconic gestures per word, and metrics of language dysfluency extracted from the discourse task as well as a metric of fluency extracted from a standardized battery. Iconic gesture production was correlated with aphasia duration, which was driven by performance during only a single task (Window), but not with other demographic metrics, such as aphasia severity or age. We also provide preliminary evidence for task differences shown through the lens of two types of iconic gestures. CONCLUSIONS: While speech-language pathologists have utilized gesture in therapy for poststroke aphasia, due to its possible facilitatory role in spoken language, there has been considerably less work in understanding how gesture differs across naturalistic tasks and how we can best utilize this information to better assess gesture in aphasia and improve multimodal treatment for aphasia. Furthermore, our results contribute to gesture theory, particularly, about the role of gesture across naturalistic tasks and its relationship with spoken language. Supplemental Material https://doi.org/10.23641/asha.14614941.


Subject(s)
Aphasia , Communication Disorders , Gestures , Humans , Speech
6.
J Speech Lang Hear Res ; 64(6): 2038-2046, 2021 06 04.
Article in English | MEDLINE | ID: mdl-34019776

ABSTRACT

Purpose The use of technology (e.g., telehealth) in clinical settings has rapidly increased, and its use in research settings continues to grow. The aim of this report is to present one potential solution to a clinical issue that of virtual and remote assessment for the purposes of spoken language research in persons with aphasia (PWA). To do so, we report detailed methods for conducting a multitimepoint (test-retest) virtual paradigm, assessing lifestyle, physiological, cognitive, and linguistic factors in persons with and without aphasia. Method Procedures for virtual assessment are detailed in a sample of adults with no brain damage (N = 24) and PWA (N = 25) on a test-retest paradigm (data collection approximately 10 ± 3 days apart). This report provides practical information about pre-assessment (e.g., recruitment, scheduling), assessment (e.g., aphasia-friendly consent presentation, investigator fidelity), and postassessment (e.g., data storage, quality check) procedures for human behavior research using a virtual platform. Results Preliminary study data are provided, indicating high retention rates, high rates of data acquisition, and feasibility. Common technological troubles and solutions are discussed, and solutions are offered. The results suggest that our pre-assessment, assessment, and postassessment procedures contributed to the success of our study. Conclusions We provide a practical methodology for conducting a multitimepoint study, with considerations for PWA, adding to the body of research on telehealth in clinical populations. Future studies should continue to evaluate telemethodology, which may be core for diversifying studies, improving study retention, and enrolling larger sample sizes. Supplemental Material https://doi.org/10.23641/asha.14608101.


Subject(s)
Aphasia , Brain Injuries , Adult , Humans , Linguistics
7.
Brain Connect ; 11(7): 543-552, 2021 09.
Article in English | MEDLINE | ID: mdl-33757303

ABSTRACT

Introduction: Stroke can induce large-scale functional reorganization of the brain; however, the spatial patterns of this reorganization remain largely unknown. Methods: Using a large (N = 116) sample of participants who were in the chronic stages of stroke, we present a systematic study of the association between brain damage and functional connectivity (FC) within the intact hemisphere. We computed correlations between regional cortical damage and contralateral FC. Results: We identified left-hemisphere regions that had the most pronounced effect on the right-hemisphere FC, and, conversely, right-hemisphere connections where the effect of damage was particularly strong. Notably, the vast majority of significant correlations were positive: damage was associated with an increase in regional contralateral connectivity. Discussion: These findings lend evidence of the reorganization of contralateral cortical networks as a response to brain damage, which is more pronounced in a set of well-connected regions where connectivity increases with the amount of damage. Impact statement The relatively large sample size combined with our best-of-breed analysis methods provides us with sufficient statistical power and spatial sensitivity to identify a set of brain regions where damage has the strongest impact on contralateral networks, and a set of contralateral functional connections that increase in strength in response to brain damage. Our results demonstrate that the brain's ability to reorganize itself after extensive damage is not distributed equally in space, but is more likely to occur in specific core regions. We believe that the associations between brain damage and increased connectivity in the "intact" hemisphere provide novel, and important, insight into the plasticity of the adult brain.


Subject(s)
Brain Injuries , Stroke , Brain/diagnostic imaging , Brain Mapping , Humans , Magnetic Resonance Imaging , Stroke/diagnostic imaging
8.
Am J Speech Lang Pathol ; 30(1S): 491-502, 2021 02 11.
Article in English | MEDLINE | ID: mdl-32585117

ABSTRACT

Purpose The heterogeneous nature of measures, methods, and analyses reported in the aphasia spoken discourse literature precludes comparison of outcomes across studies (e.g., meta-analyses) and inhibits replication. Furthermore, funding and time constraints significantly hinder collecting test-retest data on spoken discourse outcomes. This research note describes the development and structure of a working group, designed to address major gaps in the spoken discourse aphasia literature, including a lack of standardization in methodology, analysis, and reporting, as well as nominal data regarding the psychometric properties of spoken discourse outcomes. Method The initial initiatives for this working group are to (a) propose recommendations regarding standardization of spoken discourse collection, analysis, and reporting in aphasia, based on the results of an international survey and a systematic literature review and (b) create a database of test-retest spoken discourse data from individuals with and without aphasia. The survey of spoken discourse collection, analysis, and interpretation procedures was distributed to clinicians and researchers involved in aphasia assessment and rehabilitation from September to November 2019. We will publish survey results and recommend standards for collecting, analyzing, and reporting spoken discourse in aphasia. A multisite endeavor to collect test-retest spoken discourse data from individuals with and without aphasia will be initiated. This test-retest information will be contributed to a central site for transcription and analysis, and data will be subsequently openly curated. Conclusion The goal of the working group is to create recommendations for field-wide standards in methods, analysis, and reporting of spoken discourse outcomes, as has been done across other related disciplines (e.g., Consolidated Standards of Reporting Trials, Enhancing the Quality and Transparency of Health Research, Committee on Best Practice in Data Analysis and Sharing). Additionally, the creation of a database through our multisite collaboration will allow the identification of psychometrically sound outcome measures and norms that can be used by clinicians and researchers to assess spoken discourse abilities in aphasia.


Subject(s)
Aphasia , Aphasia/diagnosis , Aphasia/therapy , Humans , Psychometrics , Surveys and Questionnaires
9.
Am J Speech Lang Pathol ; 29(1): 286-298, 2020 02 07.
Article in English | MEDLINE | ID: mdl-31990598

ABSTRACT

Purpose The purpose of this study was to describe the development and implementation of a fidelity program for an ongoing, multifacility, aphasia intervention study and to explain how initial fidelity measures are being used to improve study integrity. Method A Clinical Core team developed and incorporated a fidelity plan in this study. The aims of the Clinical Core team were to (a) supervise data collection and data management at each clinical site, (b) optimize and monitor assessment fidelity, and (c) optimize and monitor treatment fidelity. Preliminary data are being used to guide ongoing efforts to preserve and improve the fidelity of this intervention study. Results Preliminary results show that specific recruitment strategies help to improve appropriate referrals and that accommodations to participants and their families help to maintain excellent retention. A streamlined and centralized training program assures the reliability of assessors and raters for the study's assessment and treatment protocols. Ongoing monitoring of both assessment and treatment tasks helps to maintain study integrity. Less-than-optimal interrater reliability data for the raters of some of the discourse measures guided the Clinical Core team to address the training and coding inconsistencies in a timely manner. Conclusions The creation of a Clinical Core team is instrumental in developing and implementing a fidelity plan for improved assessment and treatment fidelity. Intentional planning and assignment of study staff to implement and monitor ongoing fidelity measures assures that clinical data are reliable and valid. Ongoing review of the plan shows areas of strengths and weaknesses for continuing adjustments and improvement of study fidelity.


Subject(s)
Aphasia , Research Design/standards , Data Accuracy , Data Collection/standards , Data Management/standards , Humans , Reproducibility of Results
10.
J Speech Lang Hear Res ; 62(11): 3923-3936, 2019 11 22.
Article in English | MEDLINE | ID: mdl-31756156

ABSTRACT

Purpose The brain-derived neurotrophic factor (BDNF) gene has been shown to be important for synaptic plasticity in animal models. Human research has suggested that BDNF genotype may influence stroke recovery. Some studies have suggested a genotype-specific motor-related brain activation in stroke recovery. However, recovery from aphasia in relation to BDNF genotype and language-related brain activation has received limited attention. We aimed to explore functional brain activation by BDNF genotype in individuals with chronic aphasia. Consistent with findings in healthy individuals and individuals with poststroke motor impairment, we hypothesized that, among individuals with aphasia, the presence of the Met allele of the BDNF gene is associated with reduced functional brain activation compared to noncarriers of the Met allele. Method Eighty-seven individuals with chronic stroke-induced aphasia performed a naming task during functional magnetic resonance imaging scanning and submitted blood or saliva samples for BDNF genotyping. The mean number of activated voxels was compared between groups, and group-based activation maps were directly compared. Neuropsychological testing was conducted to compare language impairment between BDNF genotype groups. The Western Aphasia Battery Aphasia Quotient (Kertesz, 2007) was included as a covariate in all analyses. Results While lesion size was comparable between groups, the amount of activation, quantified as the number of activated voxels, was significantly greater in noncarriers of the Met allele (whole brain: 98,500 vs. 28,630, p < .001; left hemisphere only: 37,209 vs. 7,000, p < .001; right hemisphere only: 74,830 vs. 30,630, p < .001). This difference was most strongly expressed in the right hemisphere posterior temporal area, pre- and postcentral gyrus, and frontal lobe, extending into the white matter. Correspondingly, the atypical BDNF genotype group was found to have significantly less severe aphasia (Western Aphasia Battery Aphasia Quotient of 64.2 vs. 54.3, p = .033) and performed better on a naming task (Philadelphia Naming Test [Roach, Schwartz, Martin, Grewal, & Brecher, 1996] score of 74.7 vs. 52.8, p = .047). A region of interest analysis of intensity of activation revealed no group differences, and a direct comparison of average activation maps across groups similarly yielded null results. Conclusion BDNF genotype mediates cortical brain activation in individuals with chronic aphasia. Correspondingly, individuals carrying the Met allele present with more severe aphasia compared to noncarriers. These findings warrant further study into the effects of BDNF genotype in aphasia. Supplemental Material https://doi.org/10.23641/asha.10073147 Presentation Video https://doi.org/10.23641/asha.10257581.


Subject(s)
Aphasia/genetics , Aphasia/physiopathology , Brain-Derived Neurotrophic Factor/genetics , Cerebral Cortex/physiopathology , Adult , Aged , Aphasia/etiology , Chronic Disease , Female , Genotype , Humans , Male , Middle Aged , Stroke/complications
11.
J Cogn Neurosci ; 32(2): 256-271, 2020 02.
Article in English | MEDLINE | ID: mdl-31596169

ABSTRACT

Left-hemisphere brain damage commonly affects patients' abilities to produce and comprehend syntactic structures, a condition typically referred to as "agrammatism." The neural correlates of agrammatism remain disputed in the literature, and distributed areas have been implicated as important predictors of performance, for example, Broca's area, anterior temporal areas, and temporo-parietal areas. We examined the association between damage to specific language-related ROIs and impaired syntactic processing in acute aphasia. We hypothesized that damage to the posterior middle temporal gyrus, and not Broca's area, would predict syntactic processing abilities. One hundred four individuals with acute aphasia (<20 days poststroke) were included in the study. Structural MRI scans were obtained, and all participants completed a 45-item sentence-picture matching task. We performed an ROI-based stepwise regression analyses to examine the relation between cortical brain damage and impaired comprehension of canonical and noncanonical sentences. Damage to the posterior middle temporal gyrus was the strongest predictor for overall task performance and performance on noncanonical sentences. Damage to the angular gyrus was the strongest predictor for performance on canonical sentences, and damage to the posterior superior temporal gyrus predicted noncanonical scores when performance on canonical sentences was included as a cofactor. Overall, our models showed that damage to temporo-parietal and posterior temporal areas was associated with impaired syntactic comprehension. Our results indicate that the temporo-parietal area is crucially implicated in complex syntactic processing, whereas the role of Broca's area may be complementary.


Subject(s)
Aphasia/pathology , Aphasia/physiopathology , Comprehension/physiology , Pattern Recognition, Visual/physiology , Speech Perception/physiology , Temporal Lobe/pathology , Acute Disease , Aged , Aphasia/diagnostic imaging , Aphasia/etiology , Female , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Psycholinguistics , Stroke/complications
12.
Brain ; 142(10): 3190-3201, 2019 10 01.
Article in English | MEDLINE | ID: mdl-31501862

ABSTRACT

We sought to determine the underlying pathophysiology relating white matter hyperintensities to chronic aphasia severity. We hypothesized that: (i) white matter hyperintensities are associated with damage to fibres of any length, but to a higher percentage of long-range compared to mid- and short-range intracerebral white matter fibres; and (ii) the number of long-range fibres mediates the relationship between white matter hyperintensities and chronic post-stroke aphasia severity. We measured the severity of periventricular and deep white matter hyperintensities and calculated the number and percentages of short-, mid- and long-range white matter fibres in 48 individuals with chronic post-stroke aphasia. Correlation and mediation analyses were performed to assess the relationship between white matter hyperintensities, connectome fibre-length measures and aphasia severity as measured with the aphasia quotient of the Western Aphasia Battery-Revised (WAB-AQ). We found that more severe periventricular and deep white matter hyperintensities correlated with a lower proportion of long-range fibres (r = -0.423, P = 0.003 and r = -0.315, P = 0.029, respectively), counterbalanced by a higher proportion of short-range fibres (r = 0.427, P = 0.002 and r = 0.285, P = 0.050, respectively). More severe periventricular white matter hyperintensities also correlated with a lower proportion of mid-range fibres (r = -0.334, P = 0.020), while deep white matter hyperintensities did not correlate with mid-range fibres (r = -0.169, P = 0.250). Mediation analyses revealed: (i) a significant total effect of periventricular white matter hyperintensities on WAB-AQ (standardized beta = -0.348, P = 0.008); (ii) a non-significant direct effect of periventricular white matter hyperintensities on WAB-AQ (P > 0.05); (iii) significant indirect effects of more severe periventricular white matter hyperintensities on worse aphasia severity mediated in parallel by fewer long-range fibres (effect = -6.23, bootstrapping: standard error = 2.64, 95%CI: -11.82 to -1.56) and more short-range fibres (effect = 4.50, bootstrapping: standard error = 2.59, 95%CI: 0.16 to 10.29). We conclude that small vessel brain disease seems to affect chronic aphasia severity through a change of the proportions of long- and short-range fibres. This observation provides insight into the pathophysiology of small vessel brain disease, and its relationship with brain health and chronic aphasia severity.


Subject(s)
Aphasia/physiopathology , Cerebral Ventricles/physiology , Leukoencephalopathies/physiopathology , Adult , Aged , Aging/physiology , Brain/metabolism , Brain Diseases/physiopathology , Cerebral Ventricles/metabolism , Connectome/methods , Female , Humans , Leukoaraiosis/physiopathology , Magnetic Resonance Imaging , Male , Middle Aged , Nerve Fibers/physiology , White Matter
13.
Neuroimage Clin ; 24: 101961, 2019.
Article in English | MEDLINE | ID: mdl-31398554

ABSTRACT

Deficits in lexical retrieval are commonly observed in individuals with post-stroke aphasia. Successful lexical retrieval is related to lexical diversity, lexical sophistication, and phonological word properties; however, the crucial brain regions supporting these different features are not fully understood. We performed MRI-based lesion symptom mapping in 58 individuals with a chronic left hemisphere stroke to assess how regional damage relates to spoken discourse-extracted measures of lexical diversity, lexical sophistication, and phonological word properties. For discourse transcription and word feature analysis, we used the Computerized Language Analysis (CLAN) program, Stanford Core Natural Language Processing, Irvine Phonotactic Online Dictionary, Lexical Complexity Analyzer, and Gramulator. Lesions involving the left posterior insula and supramarginal gyri and inferior fronto-occipital fasciculus were significant predictors of utterances with, on average, lower lexical diversity. Low lexical sophistication was associated with damage to the left pole of the superior temporal gyrus. Production of words with lower phonological complexity (fewer phonemes, higher phonological similarity) was associated with damage to the left supramarginal gyrus. Our findings indicate that discourse-extracted features of lexical retrieval depend on the integrity of specific brain regions involving insular and peri-Sylvian areas. The identified regions provide insight into potentially underlying mechanisms of lexically diverse, sophisticated and phonologically complex words produced during discourse.


Subject(s)
Aphasia/pathology , Brain/pathology , Speech/physiology , Stroke/pathology , Adult , Aged , Aphasia/etiology , Aphasia/physiopathology , Brain/physiopathology , Female , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Retrospective Studies , Speech Production Measurement , Stroke/complications , Stroke/physiopathology
14.
Neurorehabil Neural Repair ; 33(9): 718-729, 2019 09.
Article in English | MEDLINE | ID: mdl-31315507

ABSTRACT

Background. A fraction of stroke survivors with chronic aphasia experience declines in language abilities over time, but the reason for this remains unclear. Objective. To evaluate the effect of leukoaraiosis on baseline aphasia severity and long-term changes in aphasia severity. This study directly compares the predictive capacity of leukoaraiosis severity to that of lesion damage, a factor known to account for a substantial proportion of variance in the degree of language impairment and recovery. Methods. Using a longitudinal database of behavioral and neuroimaging data from 35 individuals in the chronic stage of recovery after a single-event left-hemisphere stroke (9 females, mean stroke age = 55.8 ± 9.1 years, mean months poststroke at initial evaluation = 36.3 ± 40.8), we examined 2 lines of inquiry: (1) to what extent does leukoaraiosis severity at initial evaluation predict aphasia severity and (2) to what extent does leukoaraiosis severity at initial evaluation predict longitudinal change in aphasia severity. Participants underwent high-resolution magnetic resonance imaging for the purpose of lesion volume analysis and leukoaraiosis severity rating. Biographical information was also considered. Results. Lesion volume and time poststroke at initial assessment best predicted initial aphasia severity (adjusted R2 = 0.37). Leukoaraiosis severity and initial aphasia severity significantly predicted decline in language abilities at follow-up, accounting for approximately one-third of the variance (adjusted R2 = 0.33). More severe leukoaraiosis was associated with a 4.3 odds increase of decline. Conclusions. Leukoaraiosis is a significant risk factor for declining language abilities in aphasia and should be considered for better identification of individuals at risk for long-term decline, which can guide clinical decision making.


Subject(s)
Aphasia/complications , Aphasia/psychology , Language Disorders/etiology , Language Disorders/psychology , Leukoaraiosis/complications , Leukoaraiosis/psychology , Adult , Aged , Aged, 80 and over , Aphasia/diagnostic imaging , Diffusion Tensor Imaging , Female , Humans , Language Disorders/diagnostic imaging , Language Tests , Leukoaraiosis/diagnostic imaging , Longitudinal Studies , Magnetic Resonance Imaging , Male , Middle Aged , Neuroimaging , Risk Factors , Stroke/complications , Stroke/psychology , Treatment Outcome
15.
Am J Speech Lang Pathol ; 28(3): 1067-1083, 2019 08 09.
Article in English | MEDLINE | ID: mdl-31181170

ABSTRACT

Purpose Discourse analysis is commonly used to assess language ability and to evaluate language change following intervention in aphasia. The purpose of this study was to identify differences in language produced during different discourse tasks in a large aphasia group and an age- and education-matched control group. Method Four structured discourse tasks across 3 discourse types (expositional, narrative, and procedural) were evaluated in a group of adults with aphasia (n = 90) and an age-matched control group (n = 84) drawn from AphasiaBank. CLAN software was used to extract primary linguistic variables (mean length of utterance, propositional density, type-token ratio, words per minute, open-closed class word ratio, noun-verb ratio, and tokens), which served as proxies for various language abilities. Using a series of repeated-measures analyses of covariance, with significantly correlated demographic and descriptive variables as covariates, main effects of discourse type were evaluated. Results Despite an impoverished output from the aphasia group (i.e., the control group produced significantly more overall output), there was a main effect of discourse type on most primary linguistic variables in both groups, suggesting that, in adults with and without language impairments, each discourse type taxed components of the spoken language system to varying extents. Post hoc tests fleshed out these results, demonstrating that, for example, narrative discourse produced speech highest in propositional density. Conclusion Each discourse type taxes the language system in different ways, verifying the importance of using several discourse tasks and selecting the most sensitive discourse tasks when evaluating specific language abilities and outcomes.


Subject(s)
Aphasia/diagnosis , Language Tests , Outcome Assessment, Health Care/methods , Adult , Aged , Aged, 80 and over , Aphasia/therapy , Case-Control Studies , Female , Humans , Language Therapy , Linguistics , Male , Middle Aged , Narration , Task Performance and Analysis
16.
Cortex ; 117: 228-246, 2019 08.
Article in English | MEDLINE | ID: mdl-31005024

ABSTRACT

While numerous studies have explored single-word naming, few have evaluated the behavioral and neural correlates of more naturalistic language, like connected speech, which we produce every day. Here, in a retrospective analysis of 120 participants at least six months following left hemisphere stroke, we evaluated the distribution of word errors (paraphasias) and associated brain damage during connected speech (picture description) and object naming. While paraphasias in connected speech and naming shared underlying neural substrates, analysis of the distribution of paraphasias suggested that lexical-semantic load is likely reduced during connected speech. Using voxelwise lesion-symptom mapping (VLSM), we demonstrated that verbal (real word: semantically related and unrelated) and sound (phonemic and neologistic) paraphasias during both connected speech and naming loaded onto the left hemisphere ventral and dorsal streams of language, respectively. Furthermore, for the first time using both connected speech and naming data, we localized semantically related paraphasias to more anterior left hemisphere temporal cortex and unrelated paraphasias to more posterior left temporal and temporoparietal cortex. The connected speech results, in particular, highlight a gradient of specificity as one translates visual recognition from left temporo-occipital cortex to posterior and subsequently anterior temporal cortex. The robustness of VLSM results for sound paraphasias derived during connected speech was notable, in that analyses performed on sound paraphasias from the connected speech task, and not the naming task, demonstrated significant results following removal of lesion volume variance and related apraxia of speech variance. Therefore, connected speech may be a particularly sensitive task on which to evaluate further lexical-phonological processing in the brain. The results presented here demonstrate the related, though different, distribution of paraphasias during connected speech, confirm that paraphasias arising in connected speech and single-word naming likely share neural origins, and endorse the need for continued evaluation of the neural substrates of connected speech processes.


Subject(s)
Aphasia/diagnostic imaging , Brain/diagnostic imaging , Language , Nerve Net/diagnostic imaging , Speech/physiology , Stroke/diagnostic imaging , Adult , Aged , Aphasia/etiology , Aphasia/physiopathology , Brain/physiopathology , Brain Mapping , Female , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Nerve Net/physiopathology , Neural Pathways/diagnostic imaging , Neural Pathways/physiopathology , Neuropsychological Tests , Stroke/complications , Stroke/physiopathology
18.
Brain Stimul ; 11(6): 1276-1281, 2018.
Article in English | MEDLINE | ID: mdl-30150003

ABSTRACT

BACKGROUND: Several studies, including a randomized controlled trial by our group, support applying anodal tDCS (A-tDCS) to the left hemisphere during behavioral aphasia treatment to improve outcomes. A clear mechanism explaining A-tDCS's efficacy has not been established, but modulation of neuroplasticity may be involved. OBJECTIVE/HYPOTHESIS: The brain-derived neurotrophic factor (BDNF) gene influences neuroplasticity and may modulate the effects of tDCS. Utilizing data from our recently completed trial, we conducted a planned test of whether aphasia treatment outcome is influenced by interaction between A-tDCS and a single-nucleotide polymorphism of the BDNF gene, rs6265. METHODS: Seventy-four individuals with chronic stroke-induced aphasia completed 15 language therapy sessions and were randomized to receive 1 mA A-tDCS or sham tDCS (S-tDCS) to the intact left temporoparietal region for the first 20 min of each session. BDNF genotype was available for 67 participants: 37 participants had the typical val/val genotype. The remaining 30 participants had atypical BDNF genotype (Met allele carriers). The primary outcome factor was improvement in object naming at 1 week after treatment completion. Maintenance of treatment effects was evaluated at 4 and 24 weeks. RESULTS: An interaction was revealed between tDCS condition and genotype for treatment-related naming improvement (F = 4.97, p = 0.03). Participants with val/val genotype who received A-tDCS showed greater response to aphasia treatment than val/val participants who received S-tDCS, as well as the Met allele carriers, regardless of tDCS condition. CONCLUSION: Individuals with the val/val BDNF genotype are more likely to benefit from A-tDCS during aphasia treatment.


Subject(s)
Aphasia/genetics , Aphasia/therapy , Brain-Derived Neurotrophic Factor/genetics , Genotype , Transcranial Direct Current Stimulation/methods , Adult , Aphasia/diagnosis , Female , Humans , Language Therapy/trends , Male , Middle Aged , Photic Stimulation/methods , Polymorphism, Single Nucleotide/genetics , Psychomotor Performance/physiology , Stroke/diagnosis , Stroke/genetics , Stroke/therapy , Treatment Outcome
19.
J Speech Lang Hear Res ; 60(9): 2406-2415, 2017 09 18.
Article in English | MEDLINE | ID: mdl-28885640

ABSTRACT

Purpose: Relatively preserved inner speech alongside poor overt speech has been documented in some persons with aphasia (PWA), but the relationship of overt speech with inner speech is still largely unclear, as few studies have directly investigated these factors. The present study investigates the relationship of relatively preserved inner speech in aphasia with selected measures of language and cognition. Method: Thirty-eight persons with chronic aphasia (27 men, 11 women; average age 64.53 ± 13.29 years, time since stroke 8-111 months) were classified as having relatively preserved inner and overt speech (n = 21), relatively preserved inner speech with poor overt speech (n = 8), or not classified due to insufficient measurements of inner and/or overt speech (n = 9). Inner speech scores (by group) were correlated with selected measures of language and cognition from the Comprehensive Aphasia Test (Swinburn, Porter, & Al, 2004). Results: The group with poor overt speech showed a significant relationship of inner speech with overt naming (r = .95, p < .01) and with mean length of utterance produced during a written picture description (r = .96, p < .01). Correlations between inner speech and language and cognition factors were not significant for the group with relatively good overt speech. Conclusions: As in previous research, we show that relatively preserved inner speech is found alongside otherwise severe production deficits in PWA. PWA with poor overt speech may rely more on preserved inner speech for overt picture naming (perhaps due to shared resources with verbal working memory) and for written picture description (perhaps due to reliance on inner speech due to perceived task difficulty). Assessments of inner speech may be useful as a standard component of aphasia screening, and therapy focused on improving and using inner speech may prove clinically worthwhile. Supplemental Materials: https://doi.org/10.23641/asha.5303542.


Subject(s)
Aphasia/etiology , Aphasia/psychology , Speech , Stroke/complications , Adult , Aged , Aged, 80 and over , Chronic Disease , Cohort Studies , Female , Humans , Language Tests , Male , Middle Aged , Speech Production Measurement , Stroke/psychology , Young Adult
20.
Neuropsychol Rehabil ; 28(5): 818-831, 2018 Jul.
Article in English | MEDLINE | ID: mdl-26926872

ABSTRACT

Self-delivered speech therapy provides an opportunity for individualised dosage as a complement to the speech-therapy regime in the long-term rehabilitation pathway. Few apps for speech therapy have been subject to clinical trials, especially on a self-delivered platform. In a crossover design study, the Comprehensive Aphasia Test (CAT) and Cookie Theft Picture Description (CTPD) were used to measure untrained improvement in a group of chronic expressive aphasic patients after using a speech therapy app. A pilot study (n = 3) and crossover design (n = 7) comparing the therapy app with a non-language mind-game were conducted. Patients self-selected their training on the app, with a recommended use of 20 minutes per day. There was significant post-therapy improvement on the CAT and CTPD but no significant improvement after the mind-game intervention, suggesting there were language-specific effects following use of the therapy app. Improvements on the CTPD, a functional measurement of speech, suggest that a therapy app can produce practical, important changes in speech. The improvements post-therapy were not due to type of language category trained or amount of training on the app, but an inverse relationship with severity at baseline and post-therapy improvement was shown. This study suggests that self-delivered therapy via an app is beneficial for chronic expressive aphasia.


Subject(s)
Aphasia, Broca/therapy , Computers, Handheld , Speech Therapy , Therapy, Computer-Assisted , Aged , Aged, 80 and over , Aphasia, Broca/psychology , Chronic Disease , Cross-Over Studies , Female , Humans , Language , Language Tests , Male , Middle Aged , Mobile Applications , Pilot Projects , Severity of Illness Index , Treatment Outcome
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