OBJECTIVE: Bilingual healthy adults have been shown to exhibit an advantage in executive functioning (EF) that is associated with microstructural changes in white matter (WM) networks. Patients with temporal lobe epilepsy (TLE) often show EF deficits that are associated with WM compromise. In this study, we investigate whether bilingualism can increase cognitive reserve and/or brain reserve in bilingual patients with TLE, mitigating EF impairment and WM compromise. METHODS: Diffusion tensor imaging was obtained in 19 bilingual and 26 monolingual patients with TLE, 12 bilingual healthy controls (HC), and 21 monolingual HC. Fractional anisotropy (FA) and mean diffusivity (MD) were calculated for the uncinate fasciculus (Unc) and cingulum (Cing), superior frontostriatal tract (SFS), and inferior frontostriatal tract (IFS). Measures of EF included Trail Making Test-B (TMT-B) and Delis-Kaplan Executive Function System Color-Word Inhibition/Switching. Analyses of covariance were conducted to compare FA and MD of the Unc, Cing, SFS, and IFS and EF performance across groups. RESULTS: In bilingual patients, FA was lower in the ipsilateral Cing and Unc compared to all other groups. For both patient groups, MD of the ipsilateral Unc was higher relative to HC. Despite more pronounced reductions in WM integrity, bilingual patients performed similarly to monolingual TLE and both HC groups on EF measures. By contrast, monolingual patients performed worse than HC on TMT-B. In addition, differences in group means between bilingual and monolingual patients on TMT-B approached significance when controlling for the extent of WM damage (P = .071; d = 0.62), suggesting a tendency toward higher performance for bilingual patients. SIGNIFICANCE: Despite poorer integrity of regional frontal lobe WM, bilingual patients performed similarly to monolingual patients and HC on EF measures. These findings align with studies suggesting that bilingualism may provide a protective factor for individuals with neurological disease, potentially through reorganization of EF networks that promote greater cognitive reserve.
#1Anny Reyes(UCSD: University of California, San Diego)H-Index: 10
#2Vedang S. Uttarwar(UCSD: University of California, San Diego)H-Index: 5
Last. Carrie R. McDonald(UCSD: University of California, San Diego)H-Index: 38
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Abstract Objective Executive dysfunction is observed in a sizable number of patients with refractory temporal lobe epilepsy (TLE). The frontostriatal network has been proposed to play a significant role in executive functioning, however, because of the complex architecture of these tracts, it is difficult to generate measures of fiber tract microstructure using standard diffusion tensor imaging. To examine the association between frontostriatal network compromise and executive dysfunction in TLE...
#2Kevin Japardi(UCLA: University of California, Los Angeles)H-Index: 5
Last. Susan Y. Bookheimer(UCLA: University of California, Los Angeles)H-Index: 98
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Abstract Research on bilinguals with brain lesions is complicated by high patient variability, making it difficult to find well-matched controls. We benefitted from a database of over 700 patients and conducted an analysis of pre-operative functional magnetic resonance imaging data to assess language dominance in 25 early, highly proficient Spanish-English bilinguals, and 25 carefully matched monolingual controls. Our results showed that early bilingualism is associated with greater bilateral he...
#1Adam Felton(UCR: University of California, Riverside)H-Index: 4
#2David Vazquez(UCR: University of California, Riverside)H-Index: 4
Last. Christine Chiarello(UCR: University of California, Riverside)H-Index: 37
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Abstract Bilingualism represents an interesting model of possible experience-dependent alterations in brain structure. The current study examines whether interhemispheric adaptations in brain structure are associated with bilingualism. Corpus callosum volume and cortical thickness asymmetry across 13 regions of interest (selected to include critical language and bilingual cognitive control areas) were measured in a sample of Spanish-English bilinguals and age- and gender-matched monolingual indi...
Here, we review the neural correlates of cognitive control associated with bilingualism. We demonstrate that lifelong practice managing two languages orchestrates global changes to both the structure and function of the brain. Compared with monolinguals, bilinguals generally show greater gray matter volume, especially in perceptual/motor regions, greater white matter integrity, and greater functional connectivity between gray matter regions. These changes complement electroencephalography findin...
#1Richard Q. Loi(UCSD: University of California, San Diego)H-Index: 4
#2Kelly M. Leyden(UCSD: University of California, San Diego)H-Index: 10
Last. Carrie R. McDonald(UCSD: University of California, San Diego)H-Index: 38
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SummaryObjective Diffusion tensor imaging (DTI) has become a popular tool for delineating the location and extent of white matter injury in temporal lobe epilepsy (TLE). However, DTI yields nonspecific measures that are confounded by changes occurring within both the intracellular and extracellular environments. This study investigated whether an advanced diffusion method, restriction spectrum imaging (RSI) could provide a more robust measure of white matter injury in TLE relative to DTI due to ...
#2Thomas Thesen(NYU: New York University)H-Index: 11
Last. Karen Blackmon(NYU: New York University)H-Index: 16
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SummaryObjective We assessed whether presurgical resting state functional magnetic resonance imaging (fMRI) provides information for distinguishing temporal lobe epilepsy (TLE) with mesial temporal sclerosis (TLE-MTS) from TLE without MTS (TLE-noMTS). Methods Thirty-four patients with TLE and 34 sex-/age-matched controls consented to a research imaging protocol. MTS status was confirmed by histologic evaluation of surgical tissue (TLE-MTS = 16; TLE-noMTS = 18). The fractional amplitude of low-fr...
#2Jeffrey D. Riley(UCI: University of California, Irvine)H-Index: 14
Last. Grace A. Mucci(Boston Children's Hospital)H-Index: 3
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Impairments in executive skills broadly span across multiple childhood epilepsy syndromes and can adversely affect quality of life. Bilingualism has been previously shown to correlate with enhanced executive functioning in healthy individuals. This study sought to determine whether the bilingual advantage in executive functioning exists in the context of pediatric epilepsy. We retrospectively analyzed neuropsychological data in 52 children with epilepsy and compared executive function scores in ...
Recent studies of bilingualism as a protective factor in cognitive aging have reported conflicting findings, and researchers have begun to explore the methodological complications that may explain differences across studies. This article details the current research landscape and addresses several issues relevant to the study of bilingualism and late-life cognitive function: study design, establishing causal relationships, confounding factors, operationalizing bilingualism, predicting cognitive ...
Abstract Lifelong bilingualism is associated with the delayed diagnosis of dementia, suggesting bilingual experience is relevant to brain health in aging. While the effects of bilingualism on cognitive functions across the lifespan are well documented, less is known about the neural substrates underlying differential behaviour. It is clear that bilingualism affects brain regions that mediate language abilities and that these regions are at least partially overlapping with those that exhibit age-...
Recent studies suggest that learning and using a second language (L2) can affect brain structure, including the structure of white matter (WM) tracts. This observation comes from research looking at early and older bilingual individuals who have been using both their first and second languages on an everyday basis for many years. This study investigated whether young, highly immersed late bilinguals would also show structural effects in the WM that can be attributed to everyday L2 use, irrespect...
#1Marianne Farina(PUCRS: Pontifícia Universidade Católica do Rio Grande do Sul)H-Index: 3
#2Manuela Polidoro Lima(PUCRS: Pontifícia Universidade Católica do Rio Grande do Sul)H-Index: 5
Last. Tatiana Quarti Irigaray(PUCRS: Pontifícia Universidade Católica do Rio Grande do Sul)H-Index: 13
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Cognitive reserve enables individuals to preserve their cognition, despite a possible underlying brain pathology. The objective was to verify which components contribute to an indirect measurement ...
Evaluation of the cognitive level of older adults, including decisions about meeting clinical thresholds for dementia, is typically based on behavioral levels of performance. However, individuals with high cognitive reserve will outperform the levels typically associated with their brain structure, providing inaccurate assessments of their status. We define cognitive reserve as the relation between brain integrity and cognitive level, and use the case of bilingualism as a source of cognitive res...
Last. Qing Cai(ECNU: East China Normal University)H-Index: 12
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Abstract A large body of research has indicated that bilingualism may impact cognitive functions, as well as relevant aspects of brain function and structure, through continual practice in language control. The present review aimed to bring together relevant findings on the relationship between bilingualism and domain-general cognitive functions from a neural perspective. The final sample included 210 studies, covering findings regarding neural responses to bilingual language control and/or doma...
Abstract Neuroimaging evidence has suggested that Chinese-language processing differs from that of its alphabetic-language counterparts. However, the underlying white matter pathway correlations between semantic and phonological fluency in Chinese-language processing remain unknown. Thus, we investigated the differences between two verbal fluency tests on 50 participants with amnestic mild cognitive impairment (aMCI) and 36 healthy controls (HC) with respect to five groups (ventral and dorsal st...
Last. Luis A. Vega(CSUB: California State University, Bakersfield)H-Index: 3
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We first provide a critical review of the existing findings on bilingualism as a contributor to cognitive reserve from moderator-mediator warranting cause-effect research conclusions. We next address the question of direct or indirect effects between bilingualism and neurocognitive protective factors influencing the associated age-related mental deficits. The existing findings support bilingualism as a predictor and as a moderator. Third, we propose cognitive reserve models of bilingualism descr...
Research on the effects of bi-/multilingualism on brain structure has so far yielded variable patterns. Although it cannot be disputed that learning and using additional languages restructures grey (cortical, subcortical and cerebellar) and white matter in the brain, both increases and reductions in regional volume and diffusivity have been reported. This paper revisits the available evidence from simultaneous and sequential bilinguals, multilinguals, interpreters, bimodal bilinguals, children, ...