Cognitive Science Program

Improved language in chronic aphasia after self-delivered iPad speech therapy (2018)
Brielle C Stark and Elizabeth A Warburton
Neuropsychological rehabilitation, 28 (5), 818-831

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 …

Inner speech's relationship with overt speech in poststroke aphasia (2017)
Brielle C Stark, Sharon Geva and Elizabeth A Warburton
Journal of Speech, Language, and Hearing Research, 60 (9), 2406-2415

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 …

Removal of artifacts from resting-state fMRI data in stroke (2018)
Grigori Yourganov, Julius Fridriksson, Brielle Stark and Christopher Rorden
NeuroImage: Clinical, 17 297-305

Abstract

We examined the effect of lesion on the resting-state functional connectivity in chronic post-stroke patients. We found many instances of strong correlations in BOLD signal measured at different locations within the lesion, making it hard to distinguish from the connectivity between intact and strongly connected regions. Regression of the mean cerebro-spinal fluid signal did not alleviate this problem. The connectomes computed by exclusion of lesioned voxels were not good predictors of the behavioral measures. We came up with a novel method that utilizes Independent Component Analysis (as implemented in FSL MELODIC) to identify the sources of variance in the resting-state fMRI data that are driven by the lesion, and to remove this variance. The resulting functional connectomes show better correlations with the behavioral measures of speech and language, and improve the out-of-sample prediction accuracy of …

BDNF genotype and tDCS interaction in aphasia treatment (2018)
Julius Fridriksson, Jordan Elm, Brielle C Stark, Alexandra Basilakos, Chris Rorden, Souvik Sen ...
Brain stimulation, 11 (6), 1276-1281

Abstract

BackgroundSeveral 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/hypothesisThe 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. MethodsSeventy-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 …

Transcranial direct current stimulation to treat aphasia: Longitudinal analysis of a randomized controlled trial (2019)
Julius Fridriksson, Alexandra Basilakos, Brielle C Stark, Chris Rorden, Jordan Elm, Michelle Gottfried ...
Brain Stimulation: Basic, Translational, and Clinical Research in Neuromodulation, 12 (1), 190-191

Abstract

Post-stroke aphasia is a pervasive language disorder that affects communication and quality of life. Behavioral aphasia therapy is currently standard of care; however, in the chronic phase of recovery (> 6 months post stroke), gains are often minimal. A number of studies have suggested that active transcranial direct current stimulation (A-tDCS) may improve treatment outcomes when coupled with behavioral aphasia therapy. However, many of these studies included small sample sizes or only single cases. In the first randomized controlled trial of A-tDCS as adjuvant to behavioral aphasia treatment, using a futility design, our group showed that further study of A-tDCS to improve aphasia treatment outcome is warranted [1]. The trial was planned as a futility design, and the primary findings have been reported. However, as an exploratory follow-up analysis to the futility analyses reported in Fridriksson et al., we …

Non-fluent speech following stroke is caused by impaired efference copy (2017)
Lynda Feenaughty, Alexandra Basilakos, Leonardo Bonilha, Dirk-Bart den Ouden, Chris Rorden, Brielle Stark ...
Cognitive neuropsychology, 34 (6), 333-346

Abstract

Efference copy is a cognitive mechanism argued to be critical for initiating and monitoring speech: however, the extent to which breakdown of efference copy mechanisms impact speech production is unclear. This study examined the best mechanistic predictors of non-fluent speech among 88 stroke survivors. Objective speech fluency measures were subjected to a principal component analysis (PCA). The primary PCA factor was then entered into a multiple stepwise linear regression analysis as the dependent variable, with a set of independent mechanistic variables. Participants’ ability to mimic audio-visual speech (“speech entrainment response”) was the best independent predictor of non-fluent speech. We suggest that this “speech entrainment” factor reflects integrity of internal monitoring (i.e., efference copy) of speech production, which affects speech initiation and maintenance. Results support models of …

A comparison of three discourse elicitation methods in aphasia and age-matched adults: implications for language assessment and outcome (2019)
Brielle C Stark
American journal of speech-language pathology, 17-Jan

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 …

Brain-derived neurotrophic factor genotype–specific differences in cortical activation in chronic aphasia (2019)
Sigfus Kristinsson, Grigori Yourganov, Feifei Xiao, Leonardo Bonilha, Brielle C Stark, Chris Rorden ...
American Speech-Language-Hearing Association. 62 (11), 3923-3936

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 …

Long-range fibre damage in small vessel brain disease affects aphasia severity (2019)
Janina Wilmskoetter, Barbara Marebwa, Alexandra Basilakos, Julius Fridriksson, Chris Rorden, Brielle C Stark ...
Brain, 142 (10), 3190-3201

Abstract

Individuals with more extensive white matter hyperintensities (WMH) show poorer functional outcomes after stroke, but the basis for this relationship is unclear. Wilmskoetter, Marebwa et al. report that WMH are preferentially associated with damage to long-range white matter fibres and this disruption leads to more severe post-stroke aphasia.

Neural organization of speech production: A lesion-based study of error patterns in connected speech (2019)
Brielle C Stark, Alexandra Basilakos, Gregory Hickok, Chris Rorden, Leonardo Bonilha and Julius Fridriksson
Cortex, 117 228-246

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 …

"CATCH Study"-Computerised Aphasia Therapy in Chronic Aphasia: using self-administered iPad-delivered speech therapy to explore language improvements in post-stroke chronic … (2015)
BC Stark and EA Warburton
CEREBROVASCULAR DISEASES, 39 119-119

Brain Damage Associated with Impaired Sentence Processing in Acute Aphasia (2019)
Sigfus Kristinsson, Helga Thors, Grigori Yourganov, Sigridur Magnusdottir, Haukur Hjaltason, Brielle C Stark ...
Journal of cognitive neuroscience, 16-Jan

Abstract

Background: 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. Objective and Hypothesis: 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. Method: 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 …

Standardizing assessment of spoken discourse in aphasia: A working group with deliverables (2019)
Brielle C Stark, Manaswita Dutta, Laura Murray, Lucy Bryant, Davida Fromm, Brian MacWhinney ...
PsyArXiv.

Abstract

Purpose: This paper describes the development of a working group and its initiatives, which have been designed to address major gaps in the spoken discourse aphasia literature, including a lack of standardization in methodology, analysis, and reporting, and nominal data regarding the psychometric properties of spoken discourse outcomes. Method: The working group includes task forces and initiatives to: 1) 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, 2) 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 will be distributed to clinicians and researchers involved in aphasia assessment and rehabilitation. A leadership team will discuss the 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 heterogeneous nature of measures, methods, and analyses reported in the aphasia spoken discourse literature (see Bryant et al., 2016) precludes comparison of outcomes across studies (eg, meta-analyses) and inhibits replication. We will directly address this issue by creating recommendations for field-wide standards in methods …

Leukoaraiosis Is Associated With a Decline in Language Abilities in Chronic Aphasia (2019)
Alexandra Basilakos, Brielle C Stark, Lisa Johnson, Chris Rorden, Grigori Yourganov, Leonardo Bonilha ...
Neurorehabilitation and neural repair, 33 (9), 718-729

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 …

Abstract# 140: BDNF Genotype and tDCS Interaction in Aphasia Therapy (2019)
Julius Fridriksson, Jordan Elm, Brielle C Stark, Alexandra Basilakos, Chris Rorden, Souvik Sen ...
Brain Stimulation: Basic, Translational, and Clinical Research in Neuromodulation, 12 (2), e48

Abstract

Introduction: Using a double blinded randomized controlled trial, we evaluated the extent to which brain stimulation (anodal transcranial direct current stimulation [A-tDCS]) applied during speech therapy, was a futile adjunctive intervention to improve speech production (naming) in individuals with chronic post-stroke aphasia. This futility design evaluated a null hypothesis of'A-tDCS results in better treatment outcome than sham tDCS.' Methods: 74 patients with chronic aphasia (following left hemisphere stroke) received 3 weeks of speech-language therapy coupled with either A-tDCS or sham tDCS. Thirty-four subjects were randomized to receive A-tDCS (10 F; age, M= 60+-11yrs; education, M= 15+-3yrs) and 40 sham tDCS (12 F; age, M= 60+-10yrs; education, M= 14+-2yrs). The primary outcome was the ability to name common objects (performance on a sample of treated items [Naming 80] and the Philadelphia …