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Menon AJ, Malo PK, Jain S, Gandhi S, Sundarakumar JS, Rai P, Issac TG. Association between multilingualism and cognitive performance among older adults in rural southern India. J Neurosci Rural Pract 2024; 15:81-85. [PMID: 38476421 PMCID: PMC10927057 DOI: 10.25259/jnrp_376_2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 08/30/2023] [Indexed: 03/14/2024] Open
Abstract
Objectives Recent studies have shown that multilingualism may play an important role in enhancing cognitive health. The process of language acquisition constitutes a form of natural brain training, which in turn is hypothesized to increase neuroplasticity and hence, maintains the cognitive reserve. The study aimed to analyze the relationship between the number of languages known to an individual and its effect on cognitive functioning in both healthy and cognitively impaired study participants. Materials and Methods This study utilized cross-sectional (baseline) data from Srinivasapura Aging, Neuro Senescence and COGnition study, which is an ongoing community-based, longitudinal aging cohort study conducted in a rural setting in southern India. A total of 3725 participants were considered for the study. The participants were separated into two groups, namely, monolinguals (participants knowing one language) and multilingual (participants knowing more than one language). The cognitive performance of the participants was assessed using the Clinical Dementia Rating (CDR) Scale. In addition, bivariate analyses and binary logistic regression analyses were carried out. Results The result of CDR scores with respect to language category shows that, among the monolingual participants, 86.5% were healthy individuals and 13.5% were with mild cognitive impairment (MCI). Similarly, among the multilingual, 94.3% were healthy and 5.7% were with MCI. The odds ratio value derived from logistic regression (0.69 95% CI (0.5-0.9)) that an individual has a higher chance of developing cognitive impairment if he/she is a monolingual. Conclusion This study highlights that knowing more than one language might have a profound positive impact on cognitive health, thereby reducing the likelihood of developing cognitive decline.
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Affiliation(s)
| | - Palash Kumar Malo
- Centre for Brain Research, Indian Institute of Science, Bengaluru, Karnataka, India
| | - Shubham Jain
- Centre for Brain Research, Indian Institute of Science, Bengaluru, Karnataka, India
| | - Sandhya Gandhi
- Centre for Brain Research, Indian Institute of Science, Bengaluru, Karnataka, India
| | | | - Pooja Rai
- Centre for Brain Research, Indian Institute of Science, Bengaluru, Karnataka, India
| | - Thomas Gregor Issac
- Centre for Brain Research, Indian Institute of Science, Bengaluru, Karnataka, India
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2
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Mendez MF. Can Speaking More Than One Language Help Prevent Alzheimer's Disease? J Alzheimers Dis 2023; 95:363-377. [PMID: 37545240 DOI: 10.3233/jad-230285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Alzheimer's disease (AD) is an age-related neurocognitive disorder that is epidemic in the elderly population. Currently, there are limited pharmacological interventions, and this has heightened the urgency to identify potential preventable or modifiable risk factors that promote resilience to the neuropathological effects of AD. The regular use of two or more languages is one such factor that may increases cognitive reserve through the long-standing executive control involved in managing multiple languages in the brain. There is also evidence that bilingualism is associated with increased brain reserve or maintenance, particularly in frontal-executive structures and networks. This review examines the current, sometimes conflicting literature on bi/multilingualism and AD. These studies have confounding variations in the assessment of age of second language onset, language proficiency, language usage, and whether determining incidence of AD or age of symptom onset. Despite these limitations, most publications support the presence of increased frontal-executive reserve that compensates for the development of AD neuropathology and, thereby, delays the emergence of clinical symptoms of dementia by about 4-5 years. Although regularly speaking more than one language does not protect against AD neuropathology, the delay in its clinical expression has a potentially significant impact on the lifelong morbidity from this age-related disease. Learning other languages may be an important modifiable factor for delaying the clinical expression of AD in later life.
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Affiliation(s)
- Mario F Mendez
- Departments of Neurology and Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, and Neurology Service, Neurobehavior Unit, U.S. Department of Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
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Liu H, Wu L. Lifelong Bilingualism Functions as an Alternative Intervention for Cognitive Reserve Against Alzheimer's Disease. Front Psychiatry 2021; 12:696015. [PMID: 34366926 PMCID: PMC8339371 DOI: 10.3389/fpsyt.2021.696015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/04/2021] [Indexed: 11/13/2022] Open
Abstract
Bilingualism has been reported to significantly delay the onset of dementia and plays an important role in the management of Alzheimer's disease (AD), a condition inducing impairment in the brain network and cognitive decline. Cognitive reserve is associated with the adaptive maintenance of neural functions by protecting against neuropathology. Bilingualism acts as a beneficial environmental factor contributing to cognitive reserve, although some potential confounding variables still need further elucidation. In this article, the relationship between bilingualism and cognitive reserve is discussed, interpreting the advantage of bilingualism in protecting against cognitive decline. In addition, the possible brain and biochemical mechanisms, supporting the advantageous effects of bilingualism in delaying the onset of dementia, involved in bilingualism are reviewed. Effectively, bilingualism can be considered as a pharmacological intervention with no side effects. However, the investigation of the pharmacological parameters of bilingualism is still at an early stage.
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Affiliation(s)
- Haiqing Liu
- Department of Foreign Languages, School of Humanities and Social Sciences, Gannan Medical University, Ganzhou, China
| | - Longhuo Wu
- Department of Pharmacy, Gannan Medical University, Ganzhou, China
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Heredia RR, Blackburn AM, Vega LA. Moderation-Mediation Effects in Bilingualism and Cognitive Reserve. Front Psychol 2020; 11:572555. [PMID: 33101142 PMCID: PMC7554512 DOI: 10.3389/fpsyg.2020.572555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 09/09/2020] [Indexed: 01/01/2023] Open
Abstract
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 describing analytical approaches that allow testing of these models and hypotheses related to path strength and causal relationships between predictors, moderators, and mediators. Lastly and most importantly, we suggest using large datasets available via open repositories. This can aid in the testing of theoretical models, clarifying the roles of moderators and mediators, and assessing the research viability of multi-causal paths that can influence cognitive reserve. Creating collaborative datasets to test these models would greatly advance our field and identify critical variables in the study of the bilingual aging brain.
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Affiliation(s)
- Roberto R Heredia
- Department of Psychology and Communication, Texas A&M International University, Laredo, TX, United States
| | - Angélique M Blackburn
- Department of Psychology and Communication, Texas A&M International University, Laredo, TX, United States
| | - Luis A Vega
- Department of Psychology, California State University-Bakersfield, Bakersfield, CA, United States
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Hack EE, Dubin JA, Fernandes MA, Costa SM, Tyas SL. Multilingualism and Dementia Risk: Longitudinal Analysis of the Nun Study. J Alzheimers Dis 2020; 71:201-212. [PMID: 31322560 DOI: 10.3233/jad-181302] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND Multilingualism is associated with enhanced executive function and may thus prevent cognitive decline and reduce the risk of dementia. OBJECTIVE To determine whether multilingualism is associated with delayed onset or reduced risk of dementia. METHODS Dementia was diagnosed in the Nun Study, a longitudinal study of religious sisters aged 75+ years. Multilingualism was self-reported. Dementia likelihood was determined in 325 participants using discrete-time survival analysis; sensitivity analyses (n = 106) incorporated additional linguistic measures (idea density and grammatical complexity). RESULTS Multilingualism did not delay the onset of dementia. However, participants speaking four or more languages (but not two or three) were significantly less likely to develop dementia than monolinguals (OR = 0.13; 95% CI = 0.01, 0.65, adjusted for age, apolipoprotein E, and transition period). This significant protective effect of speaking four or more languages weakened (OR = 0.53; 95% CI = 0.06, 4.91) in the presence of idea density in models adjusted for education and apolipoprotein E. CONCLUSION Linguistic ability broadly was a significant predictor of dementia, although it was written linguistic ability (specifically idea density) rather than multilingualism that was the strongest predictor. The impact of language on dementia may extend beyond number of languages spoken to encompass other indicators of linguistic ability. Further research to identify the characteristics of multilingualism most salient for risk of dementia could clarify the value, target audience, and design of interventions to promote multilingualism and other linguistic training as a strategy to reduce the risk of dementia and its individual and societal impacts.
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Affiliation(s)
- Erica E Hack
- School of Public Health and Health Systems, University of Waterloo, Waterloo, ON, Canada
| | - Joel A Dubin
- Department of Statistics and Actuarial Science, and School of Public Health and Health Systems, University of Waterloo, Waterloo, ON, Canada
| | - Myra A Fernandes
- Department of Psychology, University of Waterloo, Waterloo, ON, Canada
| | - Sanduni M Costa
- School of Public Health and Health Systems, University of Waterloo, Waterloo, ON, Canada
| | - Suzanne L Tyas
- School of Public Health and Health Systems, University of Waterloo, Waterloo, ON, Canada
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Mendez MF. Bilingualism and Dementia: Cognitive Reserve to Linguistic Competency. J Alzheimers Dis 2019; 71:377-388. [DOI: 10.3233/jad-190397] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Mario F. Mendez
- V.A. Greater Los Angeles Healthcare System, Los Angeles, CA, USA
- Departments of Neurology and Psychiatry & Biobehavioral Sciences, Los Angeles, CA, USA
- David Geffen School of Medicine, University of California at Los Angeles, CA, USA
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van den Noort M, Vermeire K, Bosch P, Staudte H, Krajenbrink T, Jaswetz L, Struys E, Yeo S, Barisch P, Perriard B, Lee SH, Lim S. A Systematic Review on the Possible Relationship Between Bilingualism, Cognitive Decline, and the Onset of Dementia. Behav Sci (Basel) 2019; 9:E81. [PMID: 31340609 PMCID: PMC6680432 DOI: 10.3390/bs9070081] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 07/17/2019] [Accepted: 07/18/2019] [Indexed: 12/20/2022] Open
Abstract
A systematic review was conducted to investigate whether bilingualism has a protective effect against cognitive decline in aging and can protect against dementia. We searched the Medline, ScienceDirect, Scopus, and ERIC databases with a cut-off date of 31 March, 2019, thereby following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) protocol. Our search resulted in 34 eligible studies. Mixed results were found with respect to the protective effect of bilingualism against cognitive decline. Several studies showed a protective effect whereas other studies failed to find it. Moreover, evidence for a delay of the onset of dementia of between 4 and 5.5 years in bilingual individuals compared to monolinguals was found in several studies, but not in all. Methodological differences in the set-up of the studies seem to explain these mixed results. Lifelong bilingualism is a complex individual process, and many factors seem to influence this and need to be further investigated. This can be best achieved through large longitudinal studies with objective behavioral and neuroimaging measurements. In conclusion, although some evidence was found for a cognitive reserve-enhancing effect of lifelong bilingualism and protection against dementia, to date, no firm conclusions can be drawn.
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Affiliation(s)
- Maurits van den Noort
- Research Group of Pain and Neuroscience, Kyung Hee University, Seoul 130-701, Korea.
- Brussels Institute for Applied Linguistics, Vrije Universiteit Brussel, Brussels 1050, Belgium.
| | - Katrien Vermeire
- Department of Communication Sciences and Disorders, Long Island University (LIU) Brooklyn, Brooklyn, NY 11201, USA
| | - Peggy Bosch
- Psychiatric Research Group, LVR-Klinik Bedburg-Hau, 47511 Bedburg-Hau, Germany
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University, 6525 Nijmegen, The Netherlands
| | - Heike Staudte
- Psychiatric Research Group, LVR-Klinik Bedburg-Hau, 47511 Bedburg-Hau, Germany
| | - Trudy Krajenbrink
- Department of Medicine, Neurology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Lars Jaswetz
- Behavioural Science Institute, Radboud University, 6525 Nijmegen, The Netherlands
| | - Esli Struys
- Brussels Institute for Applied Linguistics, Vrije Universiteit Brussel, Brussels 1050, Belgium
| | - Sujung Yeo
- College of Oriental Medicine, Sang Ji University, Wonju 26339, Korea
| | - Pia Barisch
- Department of Psychology, Ruhr University Bochum, 44801 Bochum, Germany
| | - Benoît Perriard
- Department of Medicine, Neurology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Sook-Hyun Lee
- Research Group of Pain and Neuroscience, Kyung Hee University, Seoul 130-701, Korea
| | - Sabina Lim
- Research Group of Pain and Neuroscience, Kyung Hee University, Seoul 130-701, Korea.
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Nickels L, Hameau S, Nair VKK, Barr P, Biedermann B. Ageing with bilingualism: benefits and challenges. SPEECH, LANGUAGE AND HEARING 2019. [DOI: 10.1080/2050571x.2018.1555988] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Lyndsey Nickels
- Department of Cognitive Science, Macquarie University, Sydney, Australia
- ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, Sydney, Australia
| | - Solène Hameau
- Department of Cognitive Science, Macquarie University, Sydney, Australia
- ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, Sydney, Australia
| | - Vishnu K. K. Nair
- ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, Sydney, Australia
- Department of Communicative Sciences and Disorders, New York University, New York, NY, USA
| | - Polly Barr
- ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, Sydney, Australia
- The Brain and Mind Centre, University of Sydney, Sydney, Australia
| | - Britta Biedermann
- ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, Sydney, Australia
- School of Occupational Therapy, Social Work and Speech Pathology, Curtin University, Perth, Australia
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Mendez MF, Chavez D, Akhlaghipour G. Bilingualism Delays Expression of Alzheimer's Clinical Syndrome. Dement Geriatr Cogn Disord 2019; 48:281-289. [PMID: 32045913 PMCID: PMC7195235 DOI: 10.1159/000505872] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/10/2020] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVE To evaluate the effects of bilingualism on the emergence of Alzheimer's clinical syndrome. BACKGROUND Studies have proposed an increase in cognitive and neural reserve from the management and control of two languages, with a consequent delayed expression of dementia. METHODS In a clinic with a large immigrant population, we identified 253 patients with probable Alzheimer's disease (AD) with intermediate or high evidence of AD pathophysiological process. These patients were reviewed for demographic variables, native language (L1) other than English, ages of onset and presentation, Mini-Mental State Examination (MMSE), digit spans, word fluencies, naming, and memory. RESULTS Among these patients, 74 (29.2%) were bilinguals with various L1s (Farsi, Spanish, Chinese, Tagalog, Arabic, others). When compared to the 179 monolingual AD patients, those who were bilingual had significant delays in ages of onset and presentation of approximately 4 years (p = 0.003). These delays persisted despite bilinguals having worse MMSE scores on presentation. There were no significant group differences on other variables except for worse naming in English among bilinguals versus monolinguals. Caregiver/informants reported that 66 (89.2%) of the 74 bilingual AD patients had gradually regressed to the predominant use of their L1. CONCLUSIONS In line with published reports worldwide, we found that bilingualism delays the expression of Alzheimer's clinical syndrome. We also found frequent reversion to the first learned language. These findings suggest that, among bilinguals, the availability of an L1 "back-up" either facilitates compensation or masks emergence of the early symptoms of dementia.
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Affiliation(s)
- Mario F. Mendez
- V.A. Greater Los Angeles Healthcare System, Los Angeles, CA, USA,Departments of Neurology, David Geffen School of Medicine, University of California at Los Angeles, CA, USA,Psychiatry & Biobehavioral Sciences, and Medicine, David Geffen School of Medicine, University of California at Los Angeles, CA, USA
| | - Diana Chavez
- Departments of Neurology, David Geffen School of Medicine, University of California at Los Angeles, CA, USA
| | - Golnoush Akhlaghipour
- Departments of Neurology, David Geffen School of Medicine, University of California at Los Angeles, CA, USA
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Mukadam N, Green D, Livingston G. Response to commentary on "The relationship of bilingualism to cognitive decline: The Australian Longitudinal Study of Ageing". Int J Geriatr Psychiatry 2018; 33:1411. [PMID: 30024059 DOI: 10.1002/gps.4954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 06/17/2018] [Indexed: 11/07/2022]
Affiliation(s)
| | - David Green
- Division of Psychology and Language Sciences, UCL, London, UK
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Toh WX, Hartanto A, Tan QYJ, Yang H. An integrative approach to investigating bilingual advantages in cognitive decline: The Australian Longitudinal Study of Ageing. Int J Geriatr Psychiatry 2018; 33:1412-1414. [PMID: 30240510 DOI: 10.1002/gps.4920] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 04/17/2018] [Indexed: 11/08/2022]
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