Publications by authors named "Karine Marcotte"

21 Publications

  • Page 1 of 1

Neuroanatomical Correlates of Macrolinguistic Aspects in Narrative Discourse in Unilateral Left and Right Hemisphere Stroke: A Voxel-Based Morphometry Study.

J Speech Lang Hear Res 2021 May 12;64(5):1650-1665. Epub 2021 Apr 12.

Linguistics Department, School of Humanities, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil.

Background A growing body of literature has demonstrated the importance of discourse assessment in patients who suffered from brain injury, both in the left and right hemispheres, as discourse represents a key component of functional communication. However, little is known about the relationship between gray matter density and macrolinguistic processing. Purpose This study aimed to investigate this relationship in a group of participants with middle-low to low socioeconomic status. Method Twenty adults with unilateral left hemisphere ( = 10) or right hemisphere ( = 10) chronic ischemic stroke and 10 matched (age, education, and socioeconomic status) healthy controls produced three oral narratives based on sequential scenes. Voxel-based morphometry analysis was conducted using structural magnetic resonance imaging. Results Compared to healthy controls, the left hemisphere group showed cohesion impairments, whereas the right hemisphere group showed impairments in coherence and in producing macropropositions. Cohesion positively correlated with gray matter density in the right primary sensory area (PSA)/precentral gyrus and the pars opercularis. Coherence, narrativity, and index of lexical informativeness were positively associated with the left PSA/insula and the superior temporal gyrus. Macropropositions were mostly related to the left PSA/insula and superior temporal gyrus, left cingulate, and right primary motor area/insula. Discussion Overall, the present results suggest that both hemispheres are implicated in macrolinguistic processes in narrative discourse. Further studies including larger samples and with various socioeconomic status should be conducted. Supplemental Material https://doi.org/10.23641/asha.14347550.
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http://dx.doi.org/10.1044/2020_JSLHR-20-00500DOI Listing
May 2021

The Mirror Effect Plus Protocol for acute Bell's palsy: a randomised and longitudinal study on facial rehabilitation.

Acta Otolaryngol 2021 Feb 20;141(2):203-208. Epub 2020 Nov 20.

Centre de recherche du Centre intégré universitaire de santé et services sociaux du Nord-de-l'île-de-Montréal, Hôpital du Sacré-Coeur de Montréal, Montréal, QC, Canada.

Background: Small but interesting evidences suggest that facial rehabilitation for acute Bell Palsy (BP) could improve facial outcomes in patients who benefited from optimal medication, but whose symptoms are still severe two weeks after BP's onset.

Aims: This study aimed to provide preliminary evidence of the long-term effects of a new facial retraining based on motor imagery and mirror therapy, the Mirror Effect Plus Protocol (MEPP).

Material And Methods: Twenty BP patients received the standard medication for acute BP and were then randomly allocated to the treatment (MEPP) or control group, if their palsy was still at least moderate-to-severe at 14 days post onset. Three blind independent assessors graded the patients' evolution until 6 months after onset.

Results: Significant differences between the groups were not found for any measured variable; however, a trend toward better recovery was found in the treatment group for every measured variable. This trend grew bigger for patients with severe or total BP.

Conclusions: This study suggests a promising effect of the MEPP on acute severe to total BP but requires further investigation with a larger number of participants.

Significance: Facial rehabilitation should be considered as an adjunct to medication for acute and most severe degrees of BP.
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http://dx.doi.org/10.1080/00016489.2020.1842905DOI Listing
February 2021

French Translation and Validation of the Synkinesis Assessment Questionnaire.

Can J Neurol Sci 2021 May 22;48(3):425-429. Epub 2020 Sep 22.

Research Center of the Centre intégré universitaire de santé et services sociaux du Nord-de-l'île-de-Montréal, Hôpital du Sacré-Coeur, Montréal, Canada.

Synkinesis is a distressing sequela of peripheral facial palsy (PFP). This study aimed to translate and validate the Synkinesis Assessment Questionnaire (SAQ), a reliable patient-reported outcome evaluation tool for synkinesis, in French. The SAQ was translated following a standard forward-backward translation procedure. After a cognitive debriefing with 10 PFP patients, the SAQ-F was assessed amongst 50 patients for internal consistency, known-group validity, construct validity, criterion validity, and test-retest reliability. Results demonstrated that the SAQ-F was valid, reliable, and had a unidimensional structure. The SAQ-F should be accompanied by clinician-based scales, to provide valuable additional information on the severity of synkinesis.
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http://dx.doi.org/10.1017/cjn.2020.208DOI Listing
May 2021

Sleep spindles are resilient to extensive white matter deterioration.

Brain Commun 2020 13;2(2):fcaa071. Epub 2020 Jun 13.

Research Center of the Centre Intégré Universitaire de Santé et de Services Sociaux du Nord de l'Île-de-Montréal, Montreal H4J 1C5, Canada.

Sleep spindles are an essential part of non-rapid eye movement sleep, notably involved in sleep consolidation, cognition, learning and memory. These oscillatory waves depend on an interaction loop between the thalamus and the cortex, which relies on a structural backbone of thalamo-cortical white matter tracts. It is still largely unknown if the brain can properly produce sleep spindles when it underwent extensive white matter deterioration in these tracts, and we hypothesized that it would affect sleep spindle generation and morphology. We tested this hypothesis with chronic moderate to severe traumatic brain injury ( = 23; 30.5 ± 11.1 years old; 17 m/6f), a unique human model of extensive white matter deterioration, and a healthy control group ( = 27; 30.3 ± 13.4 years old; 21m/6f). Sleep spindles were analysed on a full night of polysomnography over the frontal, central and parietal brain regions, and we measured their density, morphology and sigma-band power. White matter deterioration was quantified using diffusion-weighted MRI, with which we performed both whole-brain voxel-wise analysis (Tract-Based Spatial Statistics) and probabilistic tractography (with High Angular Resolution Diffusion Imaging) to target the thalamo-cortical tracts. Group differences were assessed for all variables and correlations were performed separately in each group, corrected for age and multiple comparisons. Surprisingly, although extensive white matter damage across the brain including all thalamo-cortical tracts was evident in the brain-injured group, sleep spindles remained completely undisrupted when compared to a healthy control group. In addition, almost all sleep spindle characteristics were not associated with the degree of white matter deterioration in the brain-injured group, except that more white matter deterioration correlated with lower spindle frequency over the frontal regions. This study highlights the resilience of sleep spindles to the deterioration of all white matter tracts critical to their existence, as they conserve normal density during non-rapid eye movement sleep with mostly unaltered morphology. We show that even with such a severe traumatic event, the brain has the ability to adapt or to withstand alterations in order to conserve normal sleep spindles.
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http://dx.doi.org/10.1093/braincomms/fcaa071DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7472897PMC
June 2020

Word-finding in confrontation naming and picture descriptions produced by individuals with early post-stroke aphasia.

Clin Neuropsychol 2020 Sep 13:1-16. Epub 2020 Sep 13.

Centre de recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, Québec, Canada.

Objective: The present study aims to assess the relationship between quantitative measures of connected speech production and performance in confrontation naming in early post-stroke aphasia (8-14 days post-stroke). We collected connected speech samples elicited by a picture description task and administered a confrontation naming task to 20 individuals with early post-stroke aphasia and 20 healthy controls. Transcriptions were made in compliance with the CHAT format guidelines. Several micro- (i.e. duration, total number of words, words per minute, mean length of utterances, ratio of open- to closed-class words and noun-to-verb ratio, VOC-, repetitions, self-corrections, and phonological and semantic errors) and macrolinguistic (i.e. informativeness and efficiency) measures were extracted. We provide evidence for the presence of impairments in an array of micro- and macrolinguistic measures of speech in individuals with early post-stroke aphasia. We show that in the patient group, confrontation naming abilities most strongly relate to informativeness in a picture description task. Our findings contribute to a better understanding of the relationship between performance in confrontation naming and in connected speech production in the first days after stroke onset and also suggest that discourse analysis may provide unique, possibly more complex information.
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http://dx.doi.org/10.1080/13854046.2020.1817563DOI Listing
September 2020

Predicting Early Post-stroke Aphasia Outcome From Initial Aphasia Severity.

Front Neurol 2020 21;11:120. Epub 2020 Feb 21.

Centre de Recherche du Centre Intégré Universitaire de Santé et de Services Sociaux du Nord-de-l'Île-de-Montréal, Montreal, QC, Canada.

The greatest degree of language recovery in post-stroke aphasia takes place within the first weeks. Aphasia severity and lesion measures have been shown to be good predictors of long-term outcomes. However, little is known about their implications in early spontaneous recovery. The present study sought to determine which factors better predict early language outcomes in individuals with post-stroke aphasia. Twenty individuals with post-stroke aphasia were assessed <72 h (acute) and 10-14 days (subacute) after stroke onset. We developed a composite score (CS) consisting of several linguistic sub-tests: repetition, oral comprehension and naming. Lesion volume, lesion load and diffusion measures [fractional anisotropy (FA) and axial diffusivity (AD)] from both arcuate fasciculi (AF) were also extracted using MRI scans performed at the same time points. A series of regression analyses were performed to predict the CS at the second assessment. Among the diffusion measures, only FA from right AF was found to be a significant predictor of early subacute aphasia outcome. However, when combined in two hierarchical models with FA, age and either lesion load or lesion size, the initial aphasia severity was found to account for most of the variance ( = 0.678), similarly to the complete models ( = 0.703 and = 0.73, respectively). Initial aphasia severity was the best predictor of early post-stroke aphasia outcome, whereas lesion measures, though highly correlated, show less influence on the prediction model. We suggest that factors predicting early recovery may differ from those involved in long-term recovery.
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http://dx.doi.org/10.3389/fneur.2020.00120DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7047164PMC
February 2020

Long-term discourse outcomes and their relationship to white matter damage in moderate to severe adulthood traumatic brain injury.

Brain Lang 2020 05 17;204:104769. Epub 2020 Feb 17.

Centre de recherche du Centre intégré universitaire de santé et de services sociaux du Nord-de-l'Île-de-Montréal (Hôpital du Sacré-Coeur de Montréal), Montréal, Québec, Canada; Département de psychologie, Faculté des arts et Sciences, Université de Montréal, Montréal, Québec, Canada.

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http://dx.doi.org/10.1016/j.bandl.2020.104769DOI Listing
May 2020

Brain white matter damage and its association with neuronal synchrony during sleep.

Brain 2019 03;142(3):674-687

Research center of the Hôpital du Sacré-Coeur de Montréal, Qc, Canada.

The restorative function of sleep partly relies on its ability to deeply synchronize cerebral networks to create large slow oscillations observable with EEG. However, whether a brain can properly synchronize and produce a restorative sleep when it undergoes massive and widespread white matter damage is unknown. Here, we answer this question by testing 23 patients with various levels of white matter damage secondary to moderate to severe traumatic brain injuries (ages 18-56; 17 males, six females, 11-39 months post-injury) and compared them to 27 healthy subjects of similar age and sex. We used MRI and diffusion tensor imaging metrics (e.g. fractional anisotropy as well as mean, axial and radial diffusivities) to characterize voxel-wise white matter damage. We measured the following slow wave characteristics for all slow waves detected in N2 and N3 sleep stages: peak-to-peak amplitude, negative-to-positive slope, negative and positive phase durations, oscillation frequency, and slow wave density. Correlation analyses were performed in traumatic brain injury and control participants separately, with age as a covariate. Contrary to our hypotheses, we found that greater white matter damage mainly over the frontal and temporal brain regions was strongly correlated with a pattern of higher neuronal synchrony characterized by slow waves of larger amplitudes and steeper negative-to-positive slopes during non-rapid eye movement sleep. The same pattern of associations with white matter damage was also observed with markers of high homeostatic sleep pressure. More specifically, higher white matter damage was associated with higher slow-wave activity power, as well as with more severe complaints of cognitive fatigue. These associations between white matter damage and sleep were found only in our traumatic brain injured participants, with no such correlation in controls. Our results suggest that, contrary to previous observations in healthy controls, white matter damage does not prevent the expected high cerebral synchrony during sleep. Moreover, our observations challenge the current line of hypotheses that white matter microstructure deterioration reduces cerebral synchrony during sleep. Our results showed that the relationship between white matter and the brain's ability to synchronize during sleep is neither linear nor simple.
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http://dx.doi.org/10.1093/brain/awy348DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6391600PMC
March 2019

Test-Retest Reliability of Diffusion Measures Extracted Along White Matter Language Fiber Bundles Using HARDI-Based Tractography.

Front Neurosci 2018 14;12:1055. Epub 2019 Jan 14.

Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montreal, QC, Canada.

High angular resolution diffusion imaging (HARDI)-based tractography has been increasingly used in longitudinal studies on white matter macro- and micro-structural changes in the language network during language acquisition and in language impairments. However, test-retest reliability measurements are essential to ascertain that the longitudinal variations observed are not related to data processing. The aims of this study were to determine the reproducibility of the reconstruction of major white matter fiber bundles of the language network using anatomically constrained probabilistic tractography with constrained spherical deconvolution based on HARDI data, as well as to assess the test-retest reliability of diffusion measures extracted along them. Eighteen right-handed participants were scanned twice, one week apart. The arcuate, inferior longitudinal, inferior fronto-occipital, and uncinate fasciculi were reconstructed in the left and right hemispheres and the following diffusion measures were extracted along each tract: fractional anisotropy, mean, axial, and radial diffusivity, number of fiber orientations, mean length of streamlines, and volume. All fiber bundles showed good morphological overlap between the two scanning timepoints and the test-retest reliability of all diffusion measures in most fiber bundles was good to excellent. We thus propose a fairly simple, but robust, HARDI-based tractography pipeline reliable for the longitudinal study of white matter language fiber bundles, which increases its potential applicability to research on the neurobiological mechanisms supporting language.
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http://dx.doi.org/10.3389/fnins.2018.01055DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6339903PMC
January 2019

Therapy-Induced Neuroplasticity in Chronic Aphasia After Phonological Component Analysis: A Matter of Intensity.

Front Neurol 2018 9;9:225. Epub 2018 Apr 9.

Department of Speech-Language Pathology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.

Despite the growing evidence regarding the importance of intensity and dose in aphasia therapy, few well-controlled studies contrasting the effects of intensive and non-intensive treatment have been conducted to date. Phonological components analysis (PCA) treatment for anomia has been associated with improvements in some patients with chronic aphasia; however, the effect of treatment intensity has not yet been studied with PCA. Thus, the aim of the present study was to identify the effect of intensity on neural processing associated with word retrieval abilities after PCA treatment. We used functional magnetic resonance imaging to examine therapy-induced changes in activation during an overt naming task in two patients who suffered from a stroke in the left middle cerebral artery territory. P1 received intensive PCA treatment whereas P2 received the standard, non-intensive, PCA treatment. Behavioral results indicate that both standard and intensive conditions yielded improved naming performance with treated nouns, but the changes were only significant for the patient who received the intensive treatment. The improvements were found to be long lasting as both patients maintained improved naming at 2-months follow-ups. The associated neuroimaging data indicate that the two treatment conditions were associated with different neural activation changes. The patient who received the standard PCA showed significant increase in activation with treatment in the right anterior cingulate, as well as extensive areas in bilateral posterior and lateral cortices. By contrast, the patient who received intensive PCA showed more decreases in activation following the treatment. Unexpectedly, this patient showed subcortical increase in activation, specifically in the right caudate nucleus. We speculate that the recruitment of the caudate nucleus and the anterior cingulate in these patients reflects the need to suppress errors to improve naming. Thus, both short-term intensive and standard, non-intensive, PCA treatment can improve word retrieval in chronic aphasia, but neuroimaging data suggest that improved naming is associated with different neural activation patterns in the two treatment conditions.
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http://dx.doi.org/10.3389/fneur.2018.00225DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5900891PMC
April 2018

Normative Study of the Functional Assessment of Verbal Reasoning and Executive Strategies (FAVRES) Test in the French-Canadian Population.

J Speech Lang Hear Res 2017 08;60(8):2217-2227

Sheila MacDonald and Associates, Guelph, Ontario, Canada.

Purpose: The Functional Assessment of Verbal Reasoning and Executive Strategies (FAVRES; MacDonald, 2005) test was designed for use by speech-language pathologists to assess verbal reasoning, complex comprehension, discourse, and executive skills during performance on a set of challenging and ecologically valid functional tasks. A recent French version of this test was translated from English; however, it had not undergone standardization. The development of normative data that are linguistically and culturally sensitive to the target population is of importance. The present study aimed to establish normative data for the French version of the FAVRES, a commonly used test with native French-speaking patients with traumatic brain injury in Québec, Canada.

Method: The normative sample consisted of 181 healthy French-speaking adults from various regions across the province of Québec. Age and years of education were factored into the normative model.

Results: Results indicate that age was significantly associated with performance on time, accuracy, reasoning subskills, and rationale criteria, whereas the level of education was significantly associated with accuracy and rationale.

Conclusion: Overall, mean scores on each criterion were relatively lower than in the original English version, which reinforces the importance of using the present normative data when interpreting performance of French speakers who have sustained a traumatic brain injury.
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http://dx.doi.org/10.1044/2017_JSLHR-L-17-0012DOI Listing
August 2017

White Matter Disruption and Connected Speech in Non-Fluent and Semantic Variants of Primary Progressive Aphasia.

Dement Geriatr Cogn Dis Extra 2017 Jan-Apr;7(1):52-73. Epub 2017 Mar 2.

aToronto Rehabilitation Institute - University Health Network, Toronto, Ontario, Canada.

Differential patterns of white matter disruption have recently been reported in the non-fluent (nfvPPA) and semantic (svPPA) variants of primary progressive aphasia (PPA). No single measure is sufficient to distinguish between the PPA variants, but connected speech allows for the quantification of multiple measures. The aim of the present study was to further investigate the white matter correlates associated with connected speech features in PPA. We examined the relationship between white matter metrics and connected speech deficits using an automated analysis of transcriptions of connected speech and diffusion tensor imaging in language-related tracts. Syntactic, lexical, and semantic features were automatically extracted from transcriptions of topic-directed interviews conducted with groups of individuals with nfvPPA or svPPA as well as with a group of healthy controls. A principal component analysis was performed in order to reduce the number of language measures and yielded a five-factor solution. The results indicated that nfvPPA patients differed from healthy controls on a syntactic factor, and svPPA patients differed from controls on two semantic factors. However, the patient groups did not differ on any factor. Moreover, a correlational analysis revealed that the lexical richness factor was significantly correlated with radial diffusivity in the left inferior longitudinal fasciculus, which suggests that semantic deficits in connected speech reflect a disruption of this ventral pathway, and which is largely consistent with the results of previous studies. Using an automated approach for the analysis of connected speech combined with probabilistic tractography, the present findings demonstrate that nfvPPA patients are impaired relative to healthy controls on syntactic measures and have increased radial diffusivity in the left superior longitudinal fasciculus, whereas the svPPA group was impaired on lexico-semantic measures relative to controls and showed increased radial diffusivity in the uncinate and inferior longitudinal fasciculus bilaterally.
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http://dx.doi.org/10.1159/000456710DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5465709PMC
March 2017

Maladaptive Plasticity in Aphasia: Brain Activation Maps Underlying Verb Retrieval Errors.

Neural Plast 2016 27;2016:4806492. Epub 2016 Jun 27.

Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, 4565 Chemin Queen-Mary, Montréal, QC, Canada H3W 1W5; École d'Orthophonie et d'Audiologie, Université de Montréal, 7077 Avenue du Parc, Montréal, QC, Canada H3N 1X7.

Anomia, or impaired word retrieval, is the most widespread symptom of aphasia, an acquired language impairment secondary to brain damage. In the last decades, functional neuroimaging techniques have enabled studying the neural basis underlying anomia and its recovery. The present study aimed to explore maladaptive plasticity in persistent verb anomia, in three male participants with chronic nonfluent aphasia. Brain activation maps associated with semantic verb paraphasia occurring within an oral picture-naming task were identified with an event-related fMRI paradigm. These maps were compared with those obtained in our previous study examining adaptive plasticity (i.e., successful verb naming) in the same participants. The results show that activation patterns related to semantic verb paraphasia and successful verb naming comprise a number of common areas, contributing to both maladaptive and adaptive neuroplasticity mechanisms. This finding suggests that the segregation of brain areas provides only a partial view of the neural basis of verb anomia and successful verb naming. Therefore, it indicates the importance of network approaches which may better capture the complexity of maladaptive and adaptive neuroplasticity mechanisms in anomia recovery.
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http://dx.doi.org/10.1155/2016/4806492DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4939358PMC
August 2017

Verb production in the nonfluent and semantic variants of primary progressive aphasia: the influence of lexical and semantic factors.

Cogn Neuropsychol 2014 ;31(7-8):565-83

a Toronto Rehabilitation Institute , Toronto , Canada.

Differential patterns of impairment with respect to noun and verb production have been observed in the nonfluent and semantic variants of primary progressive aphasia. However, the factors influencing this discrepancy remain unclear. The present study evaluates verb retrieval in primary progressive aphasia using a naming task and a story completion task. Findings indicate that patients with the semantic variant are influenced by familiarity, frequency, and age of acquisition in both object and action naming, whereas patients with the nonfluent variant are not. Surprisingly, there were no differences in either group between object and action naming, presumably because the lists were well matched on pertinent variables. In the story completion task, greater impairment in semantically heavier than in semantically lighter verbs was observed for the semantic variant, and grammaticality and verb tense agreement was significantly lower in the nonfluent variant. The present findings suggest that lexicosemantic attributes affect verb production in the semantic variant, whereas both lexicosemantic and syntactic attributes affect verb production in the nonfluent variant.
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http://dx.doi.org/10.1080/02643294.2014.970154DOI Listing
March 2015

Age-related behavioural and neurofunctional patterns of second language word learning: different ways of being successful.

Brain Lang 2014 Aug 2;135:9-19. Epub 2014 Jun 2.

École d'orthophonie et audiologie, Faculté de Médecine, Université de Montréal, Montréal, Canada; Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, Canada.

This study aimed at investigating the neural basis of word learning as a function of age and word type. Ten young and ten elderly French-speaking participants were trained by means of a computerized Spanish word program. Both age groups reached a similar naming accuracy, but the elderly required significantly more time. Despite equivalent performance, distinct neural networks characterized the ceiling. While the young cohort showed subcortical activations, the elderly recruited the left inferior frontal gyrus, the left lingual gyrus and the precuneus. The learning trajectory of the elderly, the neuroimaging findings together with their performance on the Stroop suggest that the young adults relied on control processing areas whereas the elderly relied on episodic memory circuits, which may reflect resorting to better preserved cognitive resources. Finally, the recruitment of visual processing areas by the elderly may reflect the impact of the language training method used.
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http://dx.doi.org/10.1016/j.bandl.2014.04.004DOI Listing
August 2014

Default-mode network functional connectivity in aphasia: therapy-induced neuroplasticity.

Brain Lang 2013 Jan 27;124(1):45-55. Epub 2012 Dec 27.

Unité de neuroimagerie fonctionnelle, Research Center, Institut Universitaire de Gériatrie de Montréal, 4565 Queen Mary Road, Montreal, Quebec, Canada.

Previous research on participants with aphasia has mainly been based on standard functional neuroimaging analysis. Recent studies have shown that functional connectivity analysis can detect compensatory activity, not revealed by standard analysis. Little is known, however, about the default-mode network in aphasia. In the current study, we studied changes in the default-mode network in subjects with aphasia who underwent semantic feature analysis therapy. We studied nine participants with chronic aphasia and compared them to 10 control participants. For the first time, we identified the default-mode network using spatial independent component analysis, in participants with aphasia. Intensive therapy improved integration in the posterior areas of the default-mode network concurrent with language improvement. Correlations between integration and improvement did not reach significance, but the trend suggests that pre-therapy integration of the default-mode network may predict therapy outcomes. Functional connectivity allows a better understanding of the impact of semantic feature analysis in aphasia.
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http://dx.doi.org/10.1016/j.bandl.2012.11.004DOI Listing
January 2013

Therapy-induced neuroplasticity in chronic aphasia.

Neuropsychologia 2012 Jul 30;50(8):1776-86. Epub 2012 Apr 30.

Unité de neuroimagerie fonctionnelle, Research Centre Institut Universitaire de Gériatrie de Montréal, 4565 Queen-Mary Road, Montreal, Quebec, Canada.

Research on the neural substrate of aphasia recovery has consistently increased since the advent of functional neuroimaging. The evidence from therapy-induced aphasia recovery studies shows that better recovery results from the reactivation of left hemisphere function; still, the specific left hemisphere key areas that sign successful outcome with a specific therapy approach remain to be identified. Nine participants suffering from aphasia received brief and intensive therapy with Semantic Feature Analysis (SFA). Behavioural and neuroimaging data during overt picture naming were obtained prior to and after therapy. This paper reports on a group of participants having benefited from SFA, and two distinct patterns of improvement. Correlational analysis showed that differences in outcome were not related to lesion size, but were negatively correlated with damage to Broca's area (BA45). Moreover, a group analysis showed that therapy-induced recovery following SFA was characterized by (a) a significant correlation between improvement and activation in the left precentral gyrus (BA4/6) before therapy, and (b) the recruitment of the left inferior parietal lobule, an area known for its role in semantic integration, following therapy with SFA. Individual fMRI analyses showed that although adaptive brain plasticity appeared to operate differently in each patient, best responders to SFA therapy recruited less areas after training compared to participants having shown less recovery who showed a larger number of activated areas sustaining recovery. The results of the present study suggest that a significant activation of BA4/6 could indicate the use of SFA to achieve successful outcome. Also our results suggest that greater SFA improvement in chronic aphasia is associated with recruitment of areas in the left hemisphere.
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http://dx.doi.org/10.1016/j.neuropsychologia.2012.04.001DOI Listing
July 2012

Syntactic processing in bilinguals: an fNIRS study.

Brain Lang 2012 May 15;121(2):144-51. Epub 2011 Dec 15.

Université de Montréal, Canada.

The study of the neural basis of syntactic processing has greatly benefited from neuroimaging techniques. Research on syntactic processing in bilinguals has used a variety of techniques, including mainly functional magnetic resonance imaging (fMRI) and event-related potentials (ERP). This paper reports on a functional near-infrared spectroscopy (fNIRS) study on syntactic processing in highly proficient young adult speakers of Portuguese (mother tongue) (L1) and French (second language) (L2). They made a syntactic judgment of visually presented sentences, which either did or did not contain noun-verb agreement violations. The results showed that syntactic processing in both languages resulted in significant activation in anterior frontal regions of the left hemisphere and in the temporal superior posterior areas of the right hemisphere, with a more prominent activation for L2 in some areas. These findings corroborate previously reported neuroimaging evidence, showing the suitability of fNIRS for the study of syntactic processing in the bilingual brain.
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http://dx.doi.org/10.1016/j.bandl.2011.09.009DOI Listing
May 2012

Neurofunctional (re)organization underlying narrative discourse processing in aging: evidence from fNIRS.

Brain Lang 2012 May 17;121(2):174-84. Epub 2011 Nov 17.

Centre de Recherche Institut Universitaire de Gériatrie de Montréal - CRIUGM, Canada.

Relatively few studies have analyzed the mechanisms underlying the cognitive changes that affect language in the elderly, and fewer have done so for narrative discourse. The goal of this study was to explore the neurofunctional changes associated with aging for different components of narrative discourse. Functional near-infrared spectroscopy (fNIRS) and behavioral data on 10 younger adults and 10 healthy elderly participants were collected. Ten younger adults in a non-proficient second language condition were included to explore the possibility that the age-related neurofunctional reorganization partly expresses demanding resource allocation. Results show within- and across-hemispheric differences in the neurofunctional pattern of activation in the older participants with reference to the younger ones, partially shared with the low-proficiency young adults, providing support for the recognized mechanisms underlying neural reserve and compensation. fNIRS was shown to be appropriate for studying the age-related neurofunctional reorganization of complex cognitive abilities.
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http://dx.doi.org/10.1016/j.bandl.2011.09.008DOI Listing
May 2012

Impaired L1 and executive control after left basal ganglia damage in a bilingual Basque-Spanish person with aphasia.

Clin Linguist Phon 2011 Jun 31;25(6-7):480-98. Epub 2011 Mar 31.

Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal-Quebéc, Canada.

Bilinguals must focus their attention to control competing languages. In bilingual aphasia, damage to the fronto-subcortical loop may lead to pathological language switching and mixing and the attrition of the more automatic language (usually L1). We present the case of JZ, a bilingual Basque-Spanish 53-year-old man who, after haematoma in the left basal ganglia, presented with executive deficits and aphasia, characterised by more impaired language processing in Basque, his L1. Assessment with the Bilingual Aphasia Test revealed impaired spontaneous and automatic speech production and speech rate in L1, as well as impaired L2-to-L1 sentence translation. Later observation led to the assessment of verbal and non-verbal executive control, which allowed JZ's impaired performance on language tasks to be related to executive dysfunction. In line with previous research, we report the significant attrition of L1 following damage to the left basal ganglia, reported for the first time in a Basque-Spanish bilingual. Implications for models of declarative and procedural memory are discussed.
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http://dx.doi.org/10.3109/02699206.2011.563338DOI Listing
June 2011

The neural correlates of semantic feature analysis in chronic aphasia: discordant patterns according to the etiology.

Semin Speech Lang 2010 Feb 10;31(1):52-63. Epub 2010 Mar 10.

Research Center, Institut Universitaire de Gériatrie de Montréal, Montreal, Quebec, Canada.

This event-related functional magnetic resonance imaging (fMRI) study reports on the impact of semantic feature analysis (SFA) therapy on the neural substrate sustaining the recovery from severe anomia in two patients: one participant was diagnosed with primary progressive aphasia (PPA) 2 years before this study; the other participant acquired aphasia 8 years before this study. The participant with PPA showed severe progressive nonfluent aphasia (PNFA), the language profile being similar to a Broca's aphasia; the stroke patient presented with Broca's aphasia and a severe apraxia of speech (AOS). To examine the neural substrate allowing for recovery, both patients received brief and intensive therapy with SFA; behavioral and event-related (ER)-fMRI measures during oral picture naming were obtained pre- and post-therapy. Both patients benefitted from SFA to improve their naming performance. Functional MRI performances on trained and correct pretraining items were contrasted. Adaptive brain plasticity appeared to operate differently in each patient, despite the similarity of naming recovery profiles.
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http://dx.doi.org/10.1055/s-0029-1244953DOI Listing
February 2010