ArticlePDF Available

Does Bilingualism Delay the Development of Dementia?



It has been suggested that bilingualism (where individuals speak two languages) may delay the devel- opment of dementia. However, much of the research is inconclusive. Some researchers have reported that bilingualism delays the onset and diagnosis of dementia, whilst other studies have found weak or even detrimental e ects. This paper reviews a series of nine empirical studies, published up until March 2016, which investigated whether bilingualism signi cantly delays the onset of dementia. The article also explores whether the inconsistent ndings can be attributed to di erences in study designs or the de nitions of bilingualism used between studies. Based on current evidence, it appears that lifelong bilin- gualism, where individuals frequently use both languages, may be protective against dementia. However, becoming bilingual in adulthood or using the second language infrequently is unlikely to substantially delay onset of the disease.
School of Psychology, University of Leeds, Leeds, UK
Atkinson, A. L. (2016). Does Bilingualism Delay the Development
of Dementia?
Journal of European Psychology Students,
43–50, DOI:
journal of european
psychology students
Does Bilingualism Delay the Development of Dementia?
Amy L Atkinson
It has been suggested that bilingualism (where individuals speak two languages) may delay the devel-
opment of dementia. However, much of the research is inconclusive. Some researchers have reported
that bilingualism delays the onset and diagnosis of dementia, whilst other studies have found weak or
even detrimental eects. This paper reviews a series of nine empirical studies, published up until March
2016, which investigated whether bilingualism signicantly delays the onset of dementia. The article
also explores whether the inconsistent ndings can be attributed to dierences in study designs or the
denitions of bilingualism used between studies. Based on current evidence, it appears that lifelong bilin-
gualism, where individuals frequently use both languages, may be protective against dementia. However,
becoming bilingual in adulthood or using the second language infrequently is unlikely to substantially delay
onset of the disease.
Keywords: bilingualism; dementia; degree of bilingualism; language prociency; age of acquisition
Dementia is a neurodegenerative disorder that results
in cognitive decline and a marked deterioration in the
capacity to function independently (American Psychiatric
Association [APA], 2013). Patients experience memory
problems, such as difficulty recognising familiar faces or
places (APA, 2013). In addition, individuals also frequently
present with impairments in other cognitive domains,
such as language or attention (APA, 2013). The most com-
mon type of dementia is Alzheimer’s disease (AD; Ott et al.,
1995; World Health Organization, 2015), where proteins
gradually build in the brain to form plaques and tangles
(Alzheimer’s Society, 2014a; Price & Morris, 1999). This
eventually leads to the death of cells and loss of brain tis-
sue, which causes cognitive decline (Alzheimer’s Society,
2014a). Other types of dementia include vascular demen-
tia, which is caused by cell death resulting from reduced
blood flow to the brain (Alzheimer’s Society, 2014b), and
frontotemporal dementia, which occurs due to cell death
in the frontal and temporal regions of the brain and the
pathways connecting them (Alzheimer’s Society, 2013).
Dementia is the largest cause of dependency and disa-
bility in older adults, affecting approximately 47.5 million
people worldwide (WHO, 2015). It also produces large eco-
nomic burdens, almost matching those caused by cancer,
heart disease and stroke combined (Wimo, Jönsson, Bond,
Prince, & Winblad, 2013). These individual and societal
costs are set to rise rapidly in coming years with cases of
dementia predicted to triple by 2050 due to population
ageing (Roberts & Petersen, 2014; WHO, 2015). As current
treatments for dementia are poor, research has recently
shifted, with an aim of discovering methods to delay or
prevent the onset of the illness (Gold, 2015).
Although controversial, some research has demon-
strated that higher workplace complexity and educational
attainment is associated with a delayed onset of demen-
tia (Andel et al., 2005; Bennett et al., 2003; Sattler, Toro,
Schönknecht, & Schröder, 2012; Valenzuela, & Sachdev,
2006). This is thought to occur due to an increase in
cognitive reserve, which refers to an enhanced ability to
adaptively use resources to mitigate damage to the brain
(Guzmán-Vélez & Tranel, 2015; Meng & D’Arcy, 2012;
Nithianantharajah & Hannan, 2009; Stern, 2002; Stern,
2009). This enhanced cognitive reserve is proposed to
delay the clinical manifestations of dementia, thus allow-
ing individuals to function independently for longer
(Gold, 2015). Recently, it has been suggested that bilin-
gualism, which refers to the ability to speak two languages,
may also delay the development of dementia. Substantial
evidence has been found to suggest that speaking two lan-
guages alters the brain, resulting in enhanced executive
control and cognitive functioning (Abutalebi, Canini, Della
Rosa, Green, & Weekes, 2015; Bialystok, 2011; but see Paap
& Greenberg, 2013). Based on this, it has been suggested
that bilingualism may also enhance cognitive reserve, pro-
viding protection against neurological damage and thus
delaying the onset of dementia (Abutalebi, Guidi, et al.,
2015; Bialystok, 2011).
However, inconsistent findings have been reported. This
paper will therefore review studies which have investigated
whether bilingualism delays the onset of dementia. It will
also consider whether differences in study designs and
the definitions of bilingualism used between studies can
explain the inconsistent findings reported. This review
Atkinson: Does Bilingualism Delay the Development of Dementia?44
will not provide an in-depth discussion of the mechanisms
thought to link bilingualism with a delayed onset of
dementia, but interested readers should refer to Gold
(2015) or Perani and Abutalebi (2015). Several reviews
have previously been conducted in this area (Bialystok,
Craik, & Luk, 2012; Gold, 2015; Perani & Abutalebi, 2015),
but these are either out of date given the high number
of recent publications, or do not specifically investigate
whether bilingualism delays the development of demen-
tia and the factors which may affect the relationship.
Search Strategy
PsycINFO and Google Scholar were searched for relevant
articles in English published up until March 2016. The
following search strings were used: ‘bilingualism AND
cognitive reserve’ and ‘bilingualism AND dementia’. Only
original studies were included. Studies which investi-
gated associations between bilingualism and the develop-
ment or progression of other health conditions, such as
strokes, were excluded. Studies that investigated whether
bilingualism is associated with slowed progression of
dementia were also excluded, as this review was primarily
interested in exploring whether bilingualism delays onset
of the disease. Nine studies were found which met the
criteria. These are outlined in Table 1 below.
Data synthesis
The first of these studies was conducted by Bialystok
et al. in 2007. They used medical notes and interviews
to investigate whether the onset age of dementia and
the first appointment to a memory clinic in Canada sig-
nificantly differed between monolinguals and bilinguals.
Individuals were defined as bilingual if they had “spent
the majority of their lives, at least since early adulthood,
regularly using at least two languages” (Bialystok et al.,
2007, p. 460). Bilinguals were diagnosed with the disorder
and experienced symptom onset significantly later than
monolinguals. These associations were present despite
heterogeneous factors between groups which should have
benefitted the monolinguals. The monolingual group
had on average received a higher level of formal educa-
tion (12.4 years, compared to 10.8 years in the bilingual
group), a factor which has been suggested to increase cog-
nitive reserve and potentially delay the onset of dementia
(Bennett et al., 2003; Meng & D’Arcy, 2012; Sattler et al.,
2012). In addition, a much higher number of the bilingual
group were immigrants (87%, compared to 14% of the
monolinguals). As many of these immigrants arrived from
Europe after World War II, it is likely they were exposed to
more stressful life events than the non-immigrants, which
is a known risk factor for dementia (Chertkow et al., 2010;
Gollan, Salmon, Montoya, & Galasko, 2011; Guzmán-
Vélez & Tranel, 2015; Machado et al., 2014). Nevertheless,
despite these factors, a significant difference was present
between groups, leading the authors to conclude that
bilingualism markedly delays the development of demen-
tia (Bialystok et al., 2007).
Critics, however, argue that the higher levels of immi-
grants within the bilingual group may have actually
favoured the bilinguals (Craik, Bialystok, & Freedman,
2010; Guzmán-Vélez & Tranel, 2015). Although stressful,
migration requires learning and adaption to a new envi-
ronment, an experience which is cognitively stimulating
(Guzmán-Vélez & Tranel, 2015). Migration may therefore
positively impact upon cognitive functioning, potentially
increasing cognitive reserve and delaying the develop-
ment of dementia (Guzmán-Vélez & Tranel, 2015). Given
the significantly higher percentage of immigrants in the
bilingual group, it has been suggested that the beneficial
effect of migration on cognitive reserve may at least par-
tially account for the differences observed between the
monolinguals and bilinguals by Bialystok and colleagues
(Guzmán-Vélez & Tranel, 2015).
Nevertheless, bilingualism has been reported to delay
dementia even after potentially confounding variables
such as immigration and education status have been con-
trolled for (Alladi et al., 2013; Craik et al., 2010). Craik and
colleagues (2010) compared the age of symptom onset
and diagnosis in monolinguals and bilinguals diagnosed
with Probable AD in Canada. Individuals in the bilingual
group were, on average, diagnosed with dementia 4.3
years later than individuals in the monolingual group,
whilst also reporting onset of symptoms 5.1 years later.
Groups did not differ in occupation and cognitive level,
and the monolingual group had received more formal
education, leading the authors to conclude that the dif-
ferences observed between groups could be attributed to
The results were corroborated by Alladi et al. (2013),
who compared retrospective reports of symptom onset
for all types of dementia in monolinguals and bilinguals
who were all born and raised in India. Significant differ-
ences between groups were observed for several types of
dementia, including AD, frontotemporal dementia and
vascular dementia. Across all dementia types, bilinguals
were, on average, 4.5 years older at the age of onset of
dementia compared to monolinguals. These associations
were found independent of potentially confounding vari-
ables such as education status, occupation, and gender.
However, inconsistencies are present within the literature,
with some studies reporting no significant difference in the
age of symptom onset and the age of diagnosis between
monolinguals and bilinguals (Chertkow et al., 2010; Lawton,
Gasquioine, & Weimer, 2015; Yeung, St. John, Menec, &
Tyas, 2014; Zahodne, Schofield, Farrell, Stern, & Manly,
2014). Zahodne and colleagues (2014) conducted a 23-year
prospective study, following Hispanics living in the USA.
Participants were all fluent in Spanish, and were defined as
bilingual if they reported speaking English “very well”, “well”
or “not well.” They were defined as monolingual if they
reported not speaking English at all. Although bilingual-
ism was associated with initial higher scores on measures of
memory and executive function, no significant differences
were observed in the rate of cognitive decline or the propor-
tion of participants diagnosed with dementia (after control-
ling for potentially confounding variables such as education
level, gender, and age of enrollment). Similar results were
also found by Yeung et al. (2014) and Lawton et al. (2015)
who reported no significant association between bilingual-
ism and the risk of dementia development.
Atkinson: Does Bilingualism Delay the Development of Dementia? 45
Paper Method Relevant ndings
Bialystok, Craik, &
Freedman (2007)
132 with probable AD; 52 with other dementias. Recruited in Canada.
Denition of bilingualism:
Bilinguals had “spent the majority of their lives, at least since early adulthood,
regularly using at least two languages”. Monolinguals spoke only English, whilst
bilinguals spoke English and at least one other language (e.g., Polish).
Symptom onset significantly later in bilinguals, even after controlling for
demographics. First appointment at memory clinic was also significantly
later in bilinguals.
Craik, Bialystok, &
Freedman (2010).
211 participants with probable AD. Recruited in Canada.
Denition of bilingualism:
Same definition as Bialystok et al. (2007). Monolinguals spoke English. Bilinguals
spoke English and at least one other language (e.g., Yiddish).
Age of symptom onset and diagnosis significantly later in bilinguals.
No significant effect of immigration status. No interaction between immi-
gration status and language group on age of onset of symptoms or age of
diagnosis. This suggests bilingualism delays onset and diagnosis regard-
less of immigration status.
Chertkow et al. (2010). Participants:
632 participants with probable AD. Recruited in Canada.
Denition of bilingualism:
Participants were monolingual (spoke one language), bilingual (spoke two lan-
guages), or multilingual (spoke three or more languages). Definition for bilingual-
ism taken from Bialystok et al. (2007).
Multilinguals had later age of diagnosis and symptom onset than mono-
linguals. No significant differences between bilinguals and monolinguals.
In non-immigrants, English-French bilinguals diagnosed significantly
earlier than monolinguals. However, non-immigrant multilinguals diag-
nosed significantly later than non-immigrant monolinguals.
In immigrants, bilinguals diagnosed significantly later than monolin-
Gollan, Salmon,
Montoya, &
Galasko (2011).
44 bilinguals with probable AD. Recruited in the USA.
Denition of bilingualism:
Participants spoke both Spanish and English. Degree of bilingualism assessed
using the Boston Naming Test (BNT) and self-report.
Overall, higher degree of bilingualism (assessed by BNT) was associated
with a later diagnosis of AD.
Participants separated into low and high education group. Higher degree
of bilingualism only protected against dementia in low education group.
Alladi et al. (2013). Participants:
648 records of patients with dementia recruited in India. All participants were
born and raised in India. Included individuals who were illiterate.
Denition of bilingualism:
Participants were classified as monolingual (spoke one language) or bilingual
(spoke two or more languages). Bilinguals were defined as individuals “with an
ability to meet the communicative demands of the self, and the society in their
normal functioning in two or more languages in their interaction with the other
speakers of any or all of these languages” (Mohanty, 1994). Participants spoke a
variety of languages, including Telugu, Hindi, and English.
Bilinguals developed dementia significantly later than monolinguals,
even after controlling for demographic factors. No additional benefit of
speaking more than two languages.
Illiterate bilinguals developed dementia significantly later than illiterate
monolinguals, suggesting effects are not due to education.
Atkinson: Does Bilingualism Delay the Development of Dementia?46
Paper Method Relevant ndings
Zahodne, Schoeld,
Farrell, Stern &
Manly (2014).
1,067 Hispanic immigrants recruited in the USA. Records of 228 participants who
developed dementia analysed.
Denition of bilingualism:
Monolinguals spoke Spanish and bilinguals spoke Spanish and English. Partici-
pants were asked how well they speak English. If they answered “not at all”, they
were classed as monolingual. If they answered “not well”, “well” or “very well”, they
were classed as bilingual. A subset of participants completed the English-language
Wide Range Achievement Test Version 3 (WRAT-3) to ensure self-report was valid.
Higher self-reported bilingualism associated with lower chance of
dementia diagnosis, but no significant associations after controlling for
demographic factors.
Similarly, performance on the WRAT-3 did not independently predict
rates of dementia diagnosis after demographic variables controlled for.
Lawton, Gasquoine, &
Weimer (2015).
1,789 Hispanic-Americans recruited in the USA. Case records of 55 diagnosed with
probable AD and 26 with vascular dementia examined.
Denition of bilingualism:
Participants spoke Spanish and/or English. To assess language status, participants
were asked “Do you speak Spanish?” and “Do you speak English”. If participants
answered “not at all” or “not very often” about one of the languages, they were
classified as being monolingual. If they answered “very often” or “almost always” to
both, they were classified as being bilingual.
Proportion of monolinguals and bilinguals diagnosed with AD and vascu-
lar dementia did not significantly differ.
Bilinguals diagnosed later than monolinguals, though difference non-
significant. Difference remained non-significant when immigrants and
non-immigrants examined separately.
Woumans et al. (2015). Participants:
134 participants with probable AD recruited in Belgium. All native Belgians.
Denition of bilingualism:
Participants were asked how many languages they had experience using. They
were then asked how proficient they were in each language and how often they
used it. Participants were categorised as being bilingual if they estimated that they
had good proficiency in speaking, reading, writing and listening in two or more
languages, and used them both at least weekly. Monolinguals spoke Dutch or
French. Bilinguals spoke a variety of languages, including Dutch, French, Spanish,
German, and English.
Bilinguals experienced first symptoms significantly later and diagnosed
significantly later, after controlling for demographics.
Yeung, St John,
Menec & Tyas (2014)
1,616 older adults recruited in Canada.
Denition of bilingualism:
Self-report. Individuals were classified as a monolingual English speaker, a
bilingual with English as a first language, or a bilingual with English as a second
language. All participants spoke English. Bilinguals spoke English and another
language (e.g., Ukrainian, German, or French).
No significant association between speaking more than one language and
risk of dementia diagnosis.
Table 1: A Summary of Studies which Met the Inclusion Criteria.
Atkinson: Does Bilingualism Delay the Development of Dementia? 47
Further refuting the relationship, Chertkow et al. (2010)
found no significant differences in the age of symptom
onset or dementia diagnosis in monolinguals and bilin-
guals. However, protective effects of multilingualism
were reported, with individuals speaking three or more
languages diagnosed with dementia significantly later
than monolinguals. A significant interaction between
bilingualism and immigration status was also reported.
In immigrants, bilingualism was protective, delaying
dementia diagnosis by almost five years. However, in
non-immigrants, speaking two languages was actually
burdensome, with bilinguals diagnosed with dementia,
on average, 2.6 years earlier than monolinguals.
Thus, based on the aforementioned studies, the rela-
tionship between bilingualism and the development of
dementia is inconclusive. Although some studies have
reported that bilingualism is protective, others have
found no significant differences between groups or even
a detrimental effect. Caution should therefore be taken
when making recommendations on whether bilingualism
delays the onset of dementia.
However, there have been large differences in the
definitions of bilingualism used between studies (e.g.,
language proficiency required and the age of acquisition
of the second language), which may potentially explain
some of the inconsistent findings yielded. Furthermore,
studies have employed different study designs, which may
have also impacted the results found. The next section
will therefore evaluate whether these factors are likely to
be important, and whether they could potentially explain
some of the inconsistent findings reported in this research
area thus far.
Denition of bilingualism used in studies
Language prociency
An important factor which may influence the relationship
between bilingualism and the development of demen-
tia is the level of proficiency in the second language
( Antoniou, Gunasekera, & Wong, 2013; Gollan et al., 2011;
Kavé, Eyal, Shorek, & Cohen-Mansfield, 2008; Kaushans-
kaya & Prior, 2015; Zied et al., 2004). For instance, Zied
and colleagues (2004) reported that balanced bilinguals
(who use both languages proficiently) performed sig-
nificantly better on a Stroop task, measuring executive
function, than unbalanced bilinguals (who were less pro-
ficient in one language). As increased levels of executive
control may mediate the relationship between bilingual-
ism and delayed dementia development, it would follow
that the levels of language proficiency are likely to impact
on whether bilingualism delays the onset of dementia
(Abutalebi, Guidi, et al., 2015; Bialystok, 2011).
The level of proficiency required for participants to be
classified as bilingual has varied substantially between
studies, which may explain some of the inconsistent
findings reported within the research area. Indeed, in
studies which have required participants to be highly pro-
ficient in their second language, bilingualism has been
associated with delayed onset of symptoms and diagno-
sis (Bialystok et al., 2007; Craik et al., 2010; Woumans
et al., 2015). However, in studies which have used more
liberal definitions, non-significant differences have been
reported (Zahodne et al., 2014). Taken together, these
studies suggest that bilingualism may only be protec-
tive if individuals are highly proficient in both languages.
However, this suggestion is speculative and based on a
limited number of studies. Furthermore, some studies
which have used strict proficiency criteria (e.g., Chertkow
et al., 2010) have not found significant difference between
monolingual and bilingual groups, suggesting that lan-
guage proficiency cannot be the only factor responsible
for the inconsistent findings reported.
Age of acquisition of the second language
Another factor proposed to impact upon whether
bilingualism delays onset of dementia is the age of acqui-
sition of the second language (Zahodne et al., 2014).
Given that studies have used differing age of acquisition
criteria, this may potentially explain some of the incon-
sistent findings reported. In many studies reporting that
bilingualism delays the onset and diagnosis of dementia,
participants have been lifelong bilinguals (Bialystok et al.,
2007; Craik et al., 2010). Conversely, in studies where
more liberal definitions of bilingualism have been used,
no significant differences have been reported (Lawton
et al., 2015; Zahodne et al., 2014). In the study conducted
by Zahodne et al. (2014), most participants acquired
their second language during adulthood, whilst in the
study conducted by Lawton et al. (2015), no data on age
of acquisition was collected. Nevertheless, some studies
which have recruited lifelong bilinguals have found no
significant differences between groups (Chertkow et al.,
2010), suggesting that age of acquisition alone cannot
fully account for differences in findings reported between
Study design
Prospective studies which have followed healthy,
community-dwelling adults for a number of years have
typically found that bilingualism is not associated with
delayed onset or diagnosis of dementia (Lawton et al.,
2015; Yeung et al., 2014; Zahodne et al., 2014). Conversely,
retrospective studies which have investigated age of onset
or diagnosis in individuals already diagnosed with the dis-
ease have typically reported that bilingualism delays the
development of dementia (Alladi et al., 2013; Bialystok
et al., 2007; Craik et al., 2010; Gollan et al., 2011; Wou-
mans et al., 2015). Generally, prospective studies are pre-
ferred to retrospective studies as they are less affected by
potential confounds such as recall bias, where individuals
recall details incorrectly (Guzmán-Vélez & Tranel, 2015).
However, as Bialystok et al. suggested (2007), there is no
reason why bilinguals would be more likely to recall infor-
mation differently to monolinguals. Furthermore, age of
diagnosis was determined by medical records in these
studies (Alladi et al., 2013; Bialystok et al., 2007; Craik
et al., 2010; Gollan et al., 2011; Woumans et al., 2015),
which are unlikely to contain false information. Neverthe-
less, further research is needed to explore why strikingly
different findings have been reported using prospective
and retrospective studies.
Atkinson: Does Bilingualism Delay the Development of Dementia?48
Conclusions and Recommendations for Further
In conclusion, research investigating the relationship
between bilingualism and the onset of dementia has
yielded inconsistent findings. Some studies have suggested
that bilingualism protects against dementia, whilst others
have suggested that there is likely to be no benefit or
even a detrimental effect of speaking two or more lan-
guages. To some extent, these inconsistent findings can
be resolved by taking into account the sample of partici-
pants recruited and the study design used. Retrospective
studies which have used a strict definition of bilingualism
have generally found significant results, whilst prospec-
tive studies using more liberal definitions have not. Based
on the available evidence, it can therefore be concluded
that lifelong bilingualism, where both languages are used
frequently, may be protective against dementia. Delays
in the development of dementia are unlikely to occur if
participants become bilingual during adulthood or infre-
quently use their second language. As such, it should not
be recommended that individuals learn a second language
as a method for delaying or preventing the development
of dementia.
The inconsistent findings between studies could not,
however, be fully attributed to differences in the defini-
tions of bilingualism used, as some studies which have
employed strict criteria have found no protective effect of
bilingualism (Chertkow et al., 2010). Additional research
is therefore required to investigate whether bilingualism
significantly delays the development of dementia. This
research should control for potentially confounding fac-
tors such as demographic variables, whilst also carefully
controlling for language factors that may affect the rela-
tionship (such as age of acquisition of the second language
and language proficiency). Where possible, this research
should use prospective study designs, which are gener-
ally preferred to retrospective designs ( Guzmán-Vélez &
Tranel, 2015).
To conclude, lifelong bilingualism where individuals fre-
quently use both languages appears to significantly delay
dementia, though benefits are unlikely to emerge if indi-
viduals become bilingual later in life or use their second
language infrequently.
The author would like to thank Dr Jelena Havelka for
useful discussion.
Competing Interests
The author declares that they have no competing interests.
Abutalebi, J., Canini, M., Della Rosa, P. A., Green, D. W., &
Weekes, B. S. (2015). The neuroprotective effects
of bilingualism upon the inferior parietal lobule:
a structural neuroimaging study in aging Chinese
bilinguals. Journal of Neurolinguistics, 33, 3–13. DOI:
Abutalebi, J., Guidi, L., Borsa, V., Canini, M.,
Della Rosa, P. A., Parris, B. A., & Weekes, B. S.
(2015). Bilingualism provides a neural reserve for aging
populations. Neuropsychologia, 69, 201–210. DOI: http://
Alladi, S., Bak, T. H., Duggirala, V., Surampudi, B.,
Shailaja, M., Shukla, A. K., ... & Kaul, S. (2013).
Bilingualism delays age at onset of dementia,
independent of education and immigration sta-
tus. Neurology, 81(22), 1938–1944. DOI: http://dx.doi.
Alzheimer’s Society. (2013). What is fronto-
temporal dementia? Retrieved from https://
Alzheimer’s Society. (2014a). What is Alzheimer’s disease?
Retrieved from
Alzheimer’s Society. (2014b). What is vascular dementia?
Retrieved from
American Psychiatric Association. (2013). Diagnostic
and Statistical Manual of Mental Disorders (5th ed.).
Washington, DC.: American Psychiatric Publishing.
Andel, R., Crowe, M., Pedersen, N. L., Mortimer, J.,
Crimmins, E., Johansson, B., & Gatz, M. (2005).
Complexity of work and risk of Alzheimer’s disease: a
population-based study of Swedish twins. The Journals
of Gerontology Series B: Psychological Sciences and
Social Sciences, 60(5), 251–258. DOI: http://dx.doi.
Antoniou, M., Gunasekera, G. M., & Wong, P. C. (2013).
Foreign language training as cognitive therapy for
age-related cognitive decline: A hypothesis for future
research. Neuroscience & Biobehavioral Reviews, 37(10),
2689–2698. DOI:
Bennett, D. A., Wilson, R. S., Schneider, J. A.,
Evans, D. A., De Leon, C. M., Arnold, S. E., ... &
Bienias, J. L. (2003). Education modifies the relation
of AD pathology to level of cognitive function in older
persons. Neurology, 60(12), 1909–1915. DOI: http://
Bialystok, E. (2011). Reshaping the mind: the benefits
of bilingualism. Canadian Journal of Experimental
Psychology, 65(4), 229–235. DOI: http://dx.doi.
Bialystok, E., Craik, F. I., & Freedman, M. (2007).
Bilingualism as a protection against the onset of
symptoms of dementia. Neuropsychologia, 45(2),
459–464. DOI:
Bialystok, E., Craik, F. I., & Luk, G. (2012). Bilingual-
ism: consequences for mind and brain. Trends in Cog-
nitive Sciences, 16(4), 240–250. DOI: http://dx.doi.
Chertkow, H., Whitehead, V., Phillips, N.,
Wolfson, C., Atherton, J., & Bergman, H. (2010).
Multilingualism (but not always bilingualism) delays
the onset of Alzheimer disease: evidence from a
bilingual community. Alzheimer Disease & Associated
Atkinson: Does Bilingualism Delay the Development of Dementia? 49
Disorders, 24(2), 118–125. DOI: http://dx.doi.
Craik, F. I., Bialystok, E., & Freedman, M. (2010). Delaying
the onset of Alzheimer disease Bilingualism as a form of
cognitive reserve. Neurology, 75(19), 1726–1729. DOI:
Gold, B. T. (2015). Lifelong bilingualism and neural
reserve against Alzheimer’s disease: A review of
findings and potential mechanisms. Behavioural Brain
Research, 281, 9–15. DOI:
Gollan, T. H., Salmon, D. P., Montoya, R. I., &
Galasko, D. R. (2011). Degree of bilingualism pre-
dicts age of diagnosis of Alzheimer’s disease in
low-education but not in highly educated Hispan-
ics. Neuropsychologia, 49(14), 3826–3830. DOI: http://
Guzmán-Vélez, E., & Tranel, D. (2015). Does bilingual-
ism contribute to cognitive reserve? Cognitive and
neural perspectives. Neuropsychology, 29(1), 139–150.
Kaushanskaya, M., & Prior, A. (2015). Variability in the
effects of bilingualism on cognition: It is not just about
cognition, it is also about bilingualism. Bilingualism:
Language and Cognition, 18(1), 27–28. DOI: http://
Kavé, G., Eyal, N., Shorek, A., & Cohen-Manseld, J.
(2008). Multilingualism and cognitive state in the oldest
old. Psychology and aging, 23(1), 70–78. DOI: http://
Lawton, D. M., Gasquoine, P. G., & Weimer, A. A. (2015).
Age of dementia diagnosis in community dwell-
ing bilingual and monolingual Hispanic Americans.
Cortex, 66, 141–145. DOI:
Machado, A., Herrera, A. J., de Pablos, R. M.,
Espinosa-Oliva, A. M., Sarmiento, M., Ayala, A., ... &
Cano, J. (2014). Chronic stress as a risk factor for Alz-
heimer’s disease. Reviews in the Neurosciences, 25(6),
785–804. DOI:
Meng, X., & D’Arcy, C. (2012). Education and dementia
in the context of the cognitive reserve hypothesis: a
systematic review with meta-analyses and qualitative
analyses. PLoS One, 7(6), e38268. DOI: http://dx.doi.
Mohanty, A. K. (1994). Bilingualism in Multilingual
Society: Psychosocial and Pedagogical Implications.
Mysore, India: Central Institute of Indian Languages.
Nithianantharajah, J., & Hannan, A. J. (2009). The
neurobiology of brain and cognitive reserve: mental
and physical activity as modulators of brain disor-
ders. Progress in Neurobiology, 89(4), 369–382. DOI:
Ott, A., Breteler, M. M., Van Harskamp, F., Claus, J. J.,
Van Der Cammen, T. J., Grobbee, D. E., & Hofman, A.
(1995). Prevalence of Alzheimer’s disease and vascular
dementia: association with education. The Rotterdam
study. Bmj, 310(6985), 970–973. DOI: http://dx.doi.
Paap, K. R., & Greenberg, Z. I. (2013). There is no coherent
evidence for a bilingual advantage in executive pro-
cessing. Cognitive Psychology, 66(2), 232–258. DOI:
Perani, D., & Abutalebi, J. (2015). Bilingualism, demen-
tia, cognitive and neural reserve. Current Opinion
in Neurology, 28(6), 618–625. DOI: http://dx.doi.
Price, J. L., & Morris, J. C. (1999). Tangles and
plaques in nondemented aging and “preclinical”
Alzheimer’s disease. Annals of Neurology, 45(3),
358–368. DOI:
Roberts, R. O., & Petersen, R. C. (2014). Predictors of early-
onset cognitive impairment. Brain, 137(5), 1280–1281.
Sattler, C., Toro, P., Schönknecht, P., & Schröder, J. (2012).
Cognitive activity, education and socioeconomic status
as preventive factors for mild cognitive impairment and
Alzheimer‘s disease. Psychiatry Research, 196(1), 90–95.
Stern, Y. (2002). What is cognitive reserve? Theory and
research application of the reserve concept. Journal of the
International Neuropsychological Society, 8(03), 448–460.
Stern, Y. (2009). Cognitive reserve. Neuropsycho-
logia, 47(10), 2015–2028. DOI: http://dx.doi.
Valenzuela, M. J., & Sachdev, P. (2006). Brain reserve
and dementia: a systematic review. Psychological
Medicine, 36(04), 441–454. DOI: http://dx.doi.
Wimo, A., Jönsson, L., Bond, J., Prince, M., & Winblad, B.
(2013). The worldwide economic impact of dementia
2010. Alzheimer’s & Dementia, 9(1), 1–11. DOI: http://
World Health Organization. (2015). Dementia.
Retrieved from
Woumans, E., Santens, P., Sieben, A., Versijpt, J.,
Stevens, M., & Duyck, W. (2015). Bilingualism delays
clinical manifestation of Alzheimer’s disease. Bilin-
gualism: Language and Cognition, 18(03), 568–574.
Yeung, C. M., St John, P. D., Menec, V., & Tyas, S. L.
(2014). Is bilingualism associated with a lower risk of
dementia in community-living older adults? Cross-
sectional and prospective analyses. Alzheimer Disease
& Associated Disorders, 28(4), 326–332. DOI: http://
Zahodne, L. B., Schoeld, P. W., Farrell, M. T., Stern, Y., &
Manly, J. J. (2014). Bilingualism does not alter cogni-
tive decline or dementia risk among Spanish-speaking
immigrants. Neuropsychology, 28(2), 238–246. DOI:
Zied, K. M., Phillipe, A., Karine, P., Valerie, H. T.,
Ghislaine, A., & Arnaud, R. (2004). Bilingualism and
adult differences in inhibitory mechanisms: Evidence from
a bilingual Stroop task. Brain and Cognition, 54(3), 254–
256. DOI:
Atkinson: Does Bilingualism Delay the Development of Dementia?50
How to cite this article: Atkinson, A. L. (2016). Does Bilingualism Delay the Development of Dementia?
Journal of
European Psychology Students
, 7(1), 43–50, DOI:
Published: 31 August 2016
Copyright: © 2016 The Author(s). This is an open-access article distributed under the terms of the Creative Commons
Attribution 4.0 Unported License (CC-BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium,
provided the original author and source are credited. See
Journal of European Psychology Students
is a peer-reviewed open access journal published
by Ubiquity Press.
... Nitekim gelişimsel olarak farklılıkları olan bazı çocuklar için, ana dili edinmek dahi normal gelişim gösteren çocuklara göre çok daha zorlu bir görev olabilmektedir. Örneğin, bilişsel gerilikler, otizm, çeşitli dil bozuklukları dil edinme mekanizmaları üzerinde özel olumsuz sonuçlara sahiptir (Rice, 2016;Atkinson, 2016;Genesee, 2015). Bu çocuklar için, dili kullanım (pragmatik), içerik (anlambilim) ve / veya form (sözdizimi, morfoloji, fonoloji) ile ilgili kurallar özellikle zordur bu da önemli dil gecikmeleri ve dil sapmalarına yol açmaktadır. ...
z Amaç İki dilde eğitim, yaklaşık 50 yılı aşkın bir süredir birçok ülkede eğitimsel bir seçenek olarak uygulanmaktadır. Literatür incelendiğinde alanda yapılan çalışmaların genellikle derleme özellikte oldukları dikkat çekmektedir. Son yıllarda ülkemizde de giderek yaygınlaşan iki dilde okul öncesi eğitim ile ilgili planlanan bu çalışmanın amacı, erken yıllarda iki dilde eğitim alan 2-6 yaş aralığındaki çocukların iki dilli sürece adaptasyonu, geçirdikleri aşamalar ve verilen tepkilerin öğretmenlerinin gözünden incelenmesidir. Gereç ve Yöntem: Araştırmada uygun veriler elde edilebilmek için araştırma tekniklerinden nitel teknik kullanılıştır. Bu kapsamda Ankara ilinde iki dilde eğitim veren bir okul öncesi eğitim kurumundaki okul öncesi öğretmenleri ve İngilizce öğretmenleri ile yarı yapılandırılmış bireysel görüşmeler yapılmıştır. Verilerin analizinde betimsel analiz tekniği kullanılmıştır. Bulgular, Sonuç: Bu araştırmanın sonucunda, öğretmenlerin cevaplarından elde edilen bulgular çocukların genel gelişimsel özellikleri ve iki dilli eğitim sürecine etkisi, iki dilli eğitime uyum süreci, iki dilli eğitimin çocuklara etkileri, iki dilli eğitim sürecinde aile tepkileri, iki dilli eğitim ile ilgili öneriler ana temaları ile ilişkilendirilmiş, bulgular direk alıntılar şeklinde sunulmuştur. Bu çalışmanın sonuçlarının, bu alanda çalışan uzmanlara, ailelere ve iki dilde eğitim alan çocuklara olumlu çıktıları olacağı düşünülmektedir.
... However, some studies suggest that the relationship between bilingualism and the onset of dementia relies on a specific type of bilingualism. For instance, Atkinson (2016) reported that bilingualism acquired during childhood may protect against dementia, while bilingualism acquired during adulthood does not seem to have any such effect. ...
... These studies demonstrated that bilingualism is a complex phenomenon that happens in various regions in the brain not necessarily within an individual's awareness, even in infants in a stage yet to start using language as a form of communication. Also, the results showed several benefits of bilingualism in relation to personality enrichment, better cognitive functioning, 7 multitasking, positive effects on the brain, especially in older age and may have positive effects in delaying the on-set of dementia, as well as diagnosing it early on (Atkinson, 2016). ...
Language forms a significant part of human interaction. It is a phenomenon that exists across all the countries and all the cultures, and we encounter its verbal or non-verbal forms since we are born. This study was conducted in order to explore the experiences of people who speak and understand more than one language-bilinguals. Eight bilingual individuals from Europe and Africa, living in the UK, offered their perspectives and shared their experiences through semi-structured interviews. This study focused on the meaning of bilingualism to each individual, its representations, and the everyday experience of bilingualism in different contexts. Thematic analysis of the interviews revealed patterns that were identified as themes and subthemes. Main conclusions from this study are that the participants' experience of bilingualism tends to blend with their identity, and impacts their world view, and they are inclined to use the second language as their inner speech. Also expressing one's positive emotions in a second language is perceived to be easier than expressing the negative ones. Participants also reported experiencing "brain doesn't work" bilingual moments, and there were found patterns in coping strategies of dealing with such situations across the data. These understandings of bilingual experiences may involve implications for further linguistic, social and cultural, and cognitive research on bilingualism.
... As discussed above, retrospective studies addressing the relationship of bilingualism and dementia have tended to use stricter definitions of bilingualism and have more commonly observed a bilingual advantage in dementia incidence; prospective studies have employed more liberal definitions and have been less likely to find evidence of a bilingual advantage. Cross-study reviews by Atkinson (2016), Gold (2015Gold ( , 2017, and Perani & Abutalebi (2015) all arrived at this conclusion, too, and all suggested that the evidence is in favor of bilingualism delaying dementia incidence, with inconsistencies between studies arising due to study design or definitions of bilingualism. By contrast, a recent meta-analysis concluded that bilingualism offers no protection against cognitive decline (Mukadam et al. 2017), and that retrospective studies supporting the bilingual protective effect against dementia are marred by methodological confounds. ...
Full-text available
Bilingualism was once thought to result in cognitive disadvantages, but research in recent decades has demonstrated that experience with two (or more) languages confers a bilingual advantage in executive functions and may delay the incidence of Alzheimer's disease. However, conflicting evidence has emerged leading to questions concerning the robustness of the bilingual advantage for both executive functions and dementia incidence. Some investigators have failed to find evidence of a bilingual advantage; others have suggested that bilingual advantages may be entirely spurious, while proponents of the advantage case have continued to defend it. A heated debate has ensued, and the field has now reached an impasse. This review critically examines evidence for and against the bilingual advantage in executive functions, cognitive aging, and brain plasticity, before outlining how future research could shed light on this debate and advance knowledge of how experience with multiple languages affects cognition and the brain.
... A statistically analysis of data indicating benefit of bilingualism and importance of acquiring "mother linguae" in minority population group and how this influence further cognitive functions, capability for further learning including lower incidence of cognitive disorders [6,9,10]. ...
Full-text available
Abstract Objective: Studying the Arvanites a bilingual population in Greece that speak Arvanitika a dialect of Albanian language still spoken in vast areas of Greece is classified as minority language and in risk of extinction as endangered. The study aim to show the possible benefit in cognitive and cognitive related dysfunction of native speakers of Arvanitika from bilingualism . Method: This is a population cohort study including bilingual speakers without exclusion criteria, sampling in the areas where Arvanite population traditionally lived achieving a sample number statistically important of 400 responders between 2018-2022 in a population unofficially ranging from 200000-16000000 or 15% of population and the comparable the same number of monolingual Greek speaker with similar background. Conclusion: A statistically analysis of data indicating benefit of bilingualism and importance of acquiring “mother linguae” in minority population group and how this influence further cognitive functions, capability for further learning including lower incidence of cognitive disorders. Keywords: Cognition; Dementia; Speech brain processing; Albanian language; Arvanitika; Minorities; Greek language Open Access J Neurol Neurosurg 7(5): OAJNN.MS.ID.555722 (2018)
... A statistically analysis of data indicating the possible benefits of bilingualism and importance of acquiring "mother language " in this minority population group and how this would influence further cognitive functions, capability for further learning including lower incidence of cognitive disorders [5,9,10]. The TEA is the only test of attention that gives a broad overview by breaking attention down into theoretically distinct factors, which can then be used as the basis of a detailed analysis of an individual's cognitive resources. ...
... Further, a similar study by Alladi et al. (2016) comparing monolingual and bilingual stroke patients found that bilinguals had a significantly lower frequency of poststroke dementia and mild cognitive impairment but the same frequency of post-stroke aphasia. Moreover, Atkinson (2016) reviewed nine papers and concluded that frequent use of two languages over a lifetime may be protective against dementia, and that inconsistencies arise due to study design or definitions of bilingualism. This evidence supports the protective effect of bilingualism against the symptoms of dementia , as well as the later onset of symptoms of mild cognitive impairment compared to monolinguals . ...
Full-text available
One of the great challenges facing humankind in the 21st century is preserving healthy brain function in our aging population. Individuals over 60 are the fastest growing age group in the world, and by 2050, it is estimated that the number of people over the age of 60 will triple. The typical aging process involves cognitive decline related to brain atrophy, especially in frontal brain areas and regions that subserve declarative memory, loss of synaptic connections, and the emergence of neuropathological symptoms associated with dementia. The disease-state of this age-related cognitive decline is Alzheimer’s disease and other dementias, which may cause older adults to lose their independence and rely on others to live safely, burdening family members and health care systems in the process. However, there are two lines of research that offer hope to those seeking to promote healthy cognitive aging. First, it has been observed that lifestyle variables such as cognitive leisure activities can moderate the risk of Alzheimer’s disease, which has led to the development of plasticity-based interventions for older adults designed to protect against the adverse effects of cognitive decline. Second, there is evidence that lifelong bilingualism acts as a safeguard in preserving healthy brain function, possibly delaying the incidence of dementia by several years. In previous work, we have suggested that foreign language learning programs aimed at older populations are an optimal solution for building cognitive reserve because language learning engages an extensive brain network that is known to overlap with the regions negatively affected by the aging process. Here, we will outline potential future lines of research that may uncover the mechanism responsible for the emergence of language learning related brain advantages, such as language typology, bi- vs. multi-lingualism, age of acquisition, and the elements that are likely to result in the largest gains.
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.
Despite the large number of elderly bilinguals at risk for Alzheimer's disease (AD) and dementia worldwide, significant questions remain about the relationship between speaking more than one language and later cognitive decline. Bilingualism may impact on cognitive and neural reserve, time of onset of dementia symptoms and neuropathology, and linguistic competency in dementia. This review indicates increased cognitive reserve from executive (monitoring, selecting, inhibiting) control of two languages and increased neural reserve involving left frontal and related areas for language control. Many, but not all, studies indicate a delay in dementia symptom onset but worse hippocampal and mesiotemporal atrophy among bilinguals versus monolinguals with AD. In contrast, bilinguals do worse on language measures, and bilinguals with AD or dementia have difficulty maintaining and monitoring their second language. Together, these studies suggest that early-acquired and proficient bilingualism increases reserve through frontal-predominant executive control, and these executive abilities compensate for early dementia symptoms, delaying their onset but not the neuropathology of their disease. Finally, as executive control decreases further with advancing dementia, there is increasing difficulty inhibiting the dominant first language and staying in the second language. These conclusions must be interpreted with caution, given the problems inherent in this type of research; however, they do recommend more work on the pre-dementia neuroprotective effects and the dementia-related language impairments of bilingualism.
Full-text available
The current study investigated the effects of bilingualism on the clinical manifestation of Alzheimer's disease (AD) in a European sample of patients. We assessed all incoming AD patients in two university hospitals within a specified timeframe. Sixty-nine monolinguals and 65 bilinguals diagnosed with probable AD were compared for time of clinical AD manifestation and diagnosis. The influence of other potentially interacting variables was also examined. Results indicated a significant delay for bilinguals of 4.6 years in manifestation and 4.8 years in diagnosis. Our study therefore strengthens the claim that bilingualism contributes to cognitive reserve and postpones the symptoms of dementia.
Full-text available
Valian (2014) suggests that the messy state of the literature examining the effects of bilingualism on executive functioning (EF) stems from lack of clarity in how EFs are defined and measured, and from lack of control over other factors that can modulate EF. We argue that the lack of clarity in how bilingualism is defined and measured is no less problematic. We focus our commentary on two related issues.
Full-text available
It is a timely issue to understand the impact of bilingualism upon brain structure in healthy aging and upon cognitive decline given evidence of its neuroprotective effects. Plastic changes induced by bilingualism were reported in young adults in the left inferior parietal lobule (LIPL) and its right counterpart (RIPL) (Mechelli et al., 2004). Moreover, both age of second language (L2) acquisition and L2 proficiency correlated with increased grey matter (GM) in the LIPL/RIPL. However it is unknown whether such findings replicate in older bilinguals. We examined this question in an aging bilingual population from Hong Kong. Results from our Voxel Based Morphometry study show that elderly bilinguals relative to a matched monolingual control group also have increased GM volumes in the inferior parietal lobules underlining the neuroprotective effect of bilingualism. However, unlike younger adults, age of L2 acquisition did not predict GM volumes. Instead, LIPL and RIPL appear differentially sensitive to the effects of L2 proficiency and L2 exposure with LIPL more sensitive to the former and RIPL more sensitive to the latter. Our data also intimate that such differences may be more prominent for speakers of languages that are linguistically closer such as in Cantonese-Mandarin bilinguals as compared to Cantonese-English bilinguals.
Full-text available
Abstract This review aims to point out that chronic stress is able to accelerate the appearance of Alzheimer's disease (AD), proposing the former as a risk factor for the latter. Firstly, in the introduction we describe some human epidemiological studies pointing out the possibility that chronic stress could increase the incidence, or the rate of appearance of AD. Afterwards, we try to justify these epidemiological results with some experimental data. We have reviewed the experiments studying the effect of various stressors on different features in AD animal models. Moreover, we also point out the data obtained on the effect of chronic stress on some processes that are known to be involved in AD, such as inflammation and glucose metabolism. Later, we relate some of the processes known to be involved in aging and AD, such as accumulation of β-amyloid, TAU hyperphosphorylation, oxidative stress and impairement of mitochondrial function, emphasizing how they are affected by chronic stress/glucocorticoids and comparing with the description made for these processes in AD. All these data support the idea that chronic stress could be considered a risk factor for AD.
Purpose of review: We discuss the role of bilingualism as a source of cognitive reserve and we propose the putative neural mechanisms through which lifelong bilingualism leads to a neural reserve that delays the onset of dementia. Recent findings: Recent findings highlight that the use of more than one language affects the human brain in terms of anatomo-structural changes. It is noteworthy that recent evidence from different places and cultures throughout the world points to a significant delay of dementia onset in bilingual/multilingual individuals. This delay has been reported not only for Alzheimer's dementia and its prodromal mild cognitive impairment phase, but also for other dementias such as vascular and fronto-temporal dementia, and was found to be independent of literacy, education and immigrant status. Summary: Lifelong bilingualism represents a powerful cognitive reserve delaying the onset of dementia by approximately 4 years. As to the causal mechanism, because speaking more than one language heavily relies upon executive control and attention, brain systems handling these functions are more developed in bilinguals resulting in increases of gray and white matter densities that may help protect from dementia onset. These neurocognitive benefits are even more prominent when second language proficiency and exposure are kept high throughout life.
Bilingualism has been reported to delay the age of retrospective report of first symptom in dementia. This study determined if the age of clinically diagnosed Alzheimer's disease and vascular dementia occurred later for bilingual than monolingual, immigrant and U.S. born, Hispanic Americans. It involved a secondary analysis of the subset of 81 bi/monolingual dementia cases identified at yearly follow-up (1998 through 2008) using neuropsychological test results and objective diagnostic criteria from the Sacramento Area Latino Study on Aging that involved a random sampling of community dwelling Hispanic Americans (N = 1789). Age of dementia diagnosis was analyzed in a 2 × 2 (bi/monolingualism × immigrant/U.S. born) ANOVA that space revealed both main effects and the interaction were non-significant. Mean age of dementia diagnosis was descriptively (but not significantly) higher in the monolingual (M = 81.10 years) than the bilingual (M = 79.31) group. Overall, bilingual dementia cases were significantly better educated than monolinguals, but U.S. born bilinguals and monolinguals did not differ significantly in education. Delays in dementia symptomatology pertaining to bilingualism are less likely to be found in studies: (a) that use age of clinical diagnosis vs. retrospective report of first dementia symptom as the dependent variable; and (b) involve clinical cases derived from community samples rather than referrals to specialist memory clinics. Copyright © 2014 Elsevier Ltd. All rights reserved.
Objective: Cognitive reserve refers to how individuals actively utilize neural resources to cope with neuropathology to maintain cognitive functioning. The present review aims to critically examine the literature addressing the relationship between bilingualism and cognitive reserve to elucidate whether bilingualism delays the onset of cognitive and behavioral manifestations of dementia. Potential neural mechanisms behind this relationship are discussed. Method: PubMed and PsycINFO databases were searched (through January 2014) for original research articles in English or Spanish languages. The following search strings were used as keywords for study retrieval: "bilingual AND reserve," "reserve AND neural mechanisms," and "reserve AND multilingualism." Results: Growing scientific evidence suggests that lifelong bilingualism contributes to cognitive reserve and delays the onset of Alzheimer's disease symptoms, allowing bilingual individuals affected by Alzheimer's disease to live an independent and richer life for a longer time than their monolingual counterparts. Lifelong bilingualism is related to more efficient use of brain resources that help individuals maintain cognitive functioning in the presence of neuropathology. We propose multiple putative neural mechanisms through which lifelong bilinguals cope with neuropathology. The roles of immigration status, education, age of onset, proficiency, and frequency of language use on the relationship between cognitive reserve and bilingualism are considered. Conclusions: Implications of these results for preventive practices and future research are discussed.