Aging Clin Exp Res DOI 10.1007/s40520-014-0224-0
Cognitive reserve in a cross-cultural population: the case of Italian emigrants in Montreal Sara Mondini • Ramona Guarino • Gonia Jarema Eva Kehayia • Vasavan Nair • Massimo Nucci • Daniela Mapelli
Received: 26 December 2013 / Accepted: 8 April 2014 Ó Springer International Publishing Switzerland 2014
Abstract Background Cognitive reserve could be defined as the accumulation of experiences, abilities, knowledge and changes that occur throughout the lifespan. One of the most difficult changes in life is the experience of emigrating to a foreign country. Aims The present investigation aimed to compare the cognitive reserve of two paired groups of elderly: Italians living in Italy and Italians who in adult age (around 20 years) emigrated to Montreal. Both groups attended the same years of school, in Italy.
Methods Cognitive reserve was measured in the two groups by a structured and standardised questionnaire, the cognitive reserve questionnaire. Results Cognitive reserve showed to be significantly higher in the Italian-Canadian individuals (i.e. Italians who emigrated). Conclusions Emigration might act as an environmental factor that enriches people’s lifestyle and reflects itself in the amount of their cognitive reserve.
S. Mondini (&) M. Nucci D. Mapelli Department of General Psychology, University of Padua, Via Venezia 8, 35131 Padua, Italy e-mail: [email protected]
S. Mondini R. Guarino Casa di Cura Figlie di San Camillo, Cremona, via Fabio Filzi 56, Cremona, Italy S. Mondini M. Nucci D. Mapelli Human Inspired Techonology Research Centre-HIT, Padua, Italy G. Jarema De´partement de Linguistique et de Traduction, Universite´ de Montre´al; Research Centre, Institut Universitaire de Ge´riatrie de Montre´al, Montreal, Canada E. Kehayia School of Physical and Occupational Therapy, McGill University; Centre de Recherche Interdisciplinaire en Re´adaptation du Montre´al Me´tropolitain, Montreal, Canada V. Nair Department of Psychiatry, Douglas Institute, McGill University, Montreal, Canada
Keywords Cognitive reserve Multi-cultural context Elderly Emigrants
The concepts of brain reserve and cognitive reserve arise from a wide array of research on age-related cognitive decline and dementia . Cognitive reserve (CR) is hypothesised to modulate manifestation of the clinical signs of deterioration delaying the onset of dementia. Brain, indeed, handles the cognitive damage implementing pre-existing and compensatory networks and cognitive processes. CR is the resilience in withstanding age-related changes and in particular disease-related pathologies thanks to a more efficient and a more adaptive plasticity. Burden conditions as the case of mild cognitive impairment, for example, can be completely compensated by high cognitive reserve. Furthermore, epidemiological data show that high CR reduces the prevalence and incidence and postpones the onset of pathological cognitive decline such as Alzheimer’s disease or Vascular dementia . Recently, this powerful concept has been applied to a wide body of research, ranging from epidemiological to imaging studies .
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CR reflects changes in the brain itself and, in the case of brain injury, it could contribute as a compensatory structure, i.e. countervail defective processing. CR seems to be correlated with education, achievement, intelligence, leisure activities, socially integrated lifestyle and, in general, wealth of life experiences. What is the proxy or the pool of proxies that can best estimate CR? Most studies on CR, even very detailed ones, differ in their consideration of possible proxies and in their description of the evaluation of CR. Meng and D’Arcy’s  recent systematic metaanalysis, for example, shows that most research studies considered education as the single proxy of CR, and even that education was considered in different ways across studies. In some education was measured as the number of years of schooling, in others as the degree of literacy and in others still using a Likert-type or numerical scale. Professional achievement is the second very frequently considered proxy. Several works report occupation as an additional independent source of CR throughout the lifetime [3, 4]. The value of occupation depends on the cognitive load involved (e.g., white collar vs. blue collar). Perceived prestige and/or salary are also common proxies. Experimental and epidemiological evidence has also shown that premorbid engagement in leisure activities  or type of ‘‘social environment’’ and ‘‘social network’’  is sometimes considered among proxies. Nucci, Mapelli and Mondini  proposed a questionnaire (Cognitive Reserve Index questionnaire, CRIq) to measure CR using a single score (Cognitive Reserve Index, CRI) that weighs education, working activity and types of leisure activities. This questionnaire (CRIq) has been recently designed in order to combine these three main proxies taking into account the experiences occurring during an individual’s lifespan. The cultural richness of life experiences and their importance for CR estimated using the CRIq constitutes the core of the present study. The research purpose is to measure the CRI of groups of people with particular social and cultural conditions, such as emigration . Such a status might indeed contribute to increased cognitive reserve since it is open to outside influences, makes people experience new physical environments, new social conditions, new languages and new habits. In order to adapt, complex adjustment is required and wide cognitive recruitment of resources is necessarily involved. First of all, it is accompanied by the knowledge of or exposure to at least another language. Many studies  have supported being bilingual as a factor affecting cognitive reserve. However, the acquisition of a second language is not sufficient, per se. Bilingualism occurs in the great majority of cases in immigrated populations and immigrants may have more drive than non-immigrants . In other words, the fuller the life a person has had in terms of abilities and experiences, the more he/she will be able to cope with difficult cognitive tasks and social events. Such a
cognitive, social, cultural and human capital promotes cognitive reserve. The present study compared the level of CR in a group of Italian immigrants living in Montreal (Quebec, Canada) with an appropriate comparable sample of Italians living in Italy. Assuming that life changes and experiences increase cognitive reserve, it is hypothesised that the Italian-immigrant group would have a higher CR.
Methods Participants This study recruited 65 individuals (27 men) aged 65 or older. They were divided into two different samples according to the country in which they were living; all of them were native speakers of Italian and received formal education in Italy. The first sample came from the Italian community in Montreal (Italian-immigrant group, henceforth called ItalianCanadians). From this community, 34 participants (13 men) participated in the study. All of them had emigrated to Canada at around the age of 20. Only two participants were born out of Italy (one in Belgium and one in the US), but they had lived in Italy throughout their childhood. At the time of the study the Italian-Canadians had lived in Montreal, Quebec, for at least 45 years. All of them were Italian mother tongue speakers; 75 % of them also spoke French, and 50 % of them spoke a third language other than Italian and French (seven participants only spoke basic English or French. However, they managed to cope very well with the most diverse situations in a multi-cultural and multilingual environment). Their mean age was 74.14 years with 8.14 years of formal education. A second sample (Italian group) was composed of 31 individuals (14 men) who had lived in different regions of Italy throughout their life. Their mean age was 77.13 with 6.39 years of formal education. The two groups did not differ in age (t63 = 1.53; p = 0.13) and years of education (t63 = 1.80; p = 0.08). All participants were initially assessed with the Italian version of the MMSE  and the Italian version of the MoCA  in order to exclude people with suspected cognitive decline. Only two participants were excluded from the study because their score at the MMSE was below the cut-off of 24/30. Furthermore, the Italian-Canadian group underwent a detailed language-background questionnaire (the first 50 questions from the Bilingual Aphasia Test  to ensure their well-preserved proficiency of the Italian language. The present study has been approved by the local Ethics committee ‘‘Ethics committee of the Scientific research area of Psychology, School of Psychology University of Padua’’ http://ethos.psy.unipd.it.
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After being informed of the scientific research, but not of its goal or main hypothesis, all participants gave their written consent to be interviewed and tested.
Table 1 Mean values (standard deviation), t test, p values, Cohen’s d of CRIq in the Italian-Canadian and Italian groups on the CRI questionnaire ItalianCanadians
Material and procedures A trained psychologist tested them individually. Their cognitive reserve was quantified through the Italian version of the Cognitive Reserve Index questionnaire (CRIq ). This questionnaire collects information on three different aspects of an individual’s life and gives scores accordingly: one total score (CRI) and three different sub-scores for each section (CRI-Education, CRI-WorkingActivity and CRILeisureTime). The questionnaire includes these three aspects of life as they are the most frequently used proxies according to the literature. CRI-Education refers to years of schooling plus possible training courses (each lasting at least 6 months); the raw score of this section is the sum of these two values. CRI-WorkingActivity registers the professions carried out during adulthood, classified into five different levels of working activities according to the degree of intellectual involvement and personal responsibility: unskilled, manual work (e.g., farmer, car driver, call centre operator); skilled manual work (e.g., craftsman, clerk, hairdresser); skilled non-manual or technical work (e.g., trader, kindergarten teacher, real estate agent); professional occupation (e.g., lawyer, psychologist, physician); highly intellectual occupation (e.g., university professor, judge, top manager). The raw score of this section was the result of the years of working activity multiplied by the cognitive level of occupation. CRI-LeisureTime: cognitively stimulating occupations carried out during leisure time (outside work or school time). The sixteen items were selected using the item response theory , by either excluding redundant, nondiscriminative items or by combining some of them. These activities were related to various intellectual accomplishments (e.g., reading newspapers or books, playing music), social activities (participation in charitable activities, going to a museum, travelling) and physical activities (sports, dancing). The frequency (i.e. never/rare, often/always) and the number of years (how long each activity had been carried out) were recorded. The raw score of this section was the total number of years of activity for which frequency was often/always. A score related to the number of children had, was also included. The normative data of this questionnaire refer to more than 600 Italian participants. The total CRIq score obtained from the normative sample was the average of the three sub-scores, standardised and transposed to a scale with M = 100 and SD = 15. The higher the CRI, the higher the estimated CR. The CRI of a person could be classified according with the norms into five ordered levels: low (\70), medium–low (70–84), medium (85–114), medium–high (115–130) and high (more
* Significance alpha = 0.05
than 130). The questionnaire is available at http://cri.psy. unipd.it in the Italian, English, French, German, and Spanish versions.
Results The cognitive reserve (total CRI and all sub-sections) of the two groups (i.e. 34 Italian-Canadians and 31 Italians) was compared. All statistical analyses were performed on raw scores using R, release 2.15.1. The Italian-Canadian group showed a CRI total score (mean 100.65) significantly higher than the Italian group (mean 91.10). Despite the fact that in all of the three subsections of the questionnaire the Italian-Canadian group had higher scores than the Italians (CRI-Education, 98.9 vs. 93.8, CRI-WorkingActivity, 100.6 vs. 90.0; CRI-LeisureTime, 102.2 vs. 97.1) and although Cohen’s d (see Table 1) is quite high, none of these single differences per se reached statistical significance. This result highlights the importance of considering more than one factor when measuring cognitive reserve. Indeed, cognitive reserve cannot be considered as the result of simply the number of years of schooling and not even the level or number of years of working activity by itself, and neither the types and the number of activities carried out during leisure. Cognitive Reserve is instead something more of all these factors, i.e. the combination of a multitude of activities taken together that characterise the life of a person (as evaluated using the CRIq). Table 1 reports mean values (and standard deviations), t test, p values and Cohen’s d.
Discussion To our knowledge this is the first study that investigates the relationship between cognitive reserve and emigration. The
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main finding of this research is that even if the two groups did not differ in age and education (all participants attended school in Italy), the Italian-Canadians have a significantly higher CR than the Italians. This concept of cognitive reserve is very promising giving a powerful contribution to better understand, diagnose and classify cognitive deficits, taking into account the cultural environment people lived in. The Italian-Canadians emigrated to Canada at the age of twenty, thus the change in their cultural environment occurred in adulthood. It cannot be ruled out the possibility that when they were young, Italians who decided to emigrate to Canada, already had certain cognitive advantages. However, the equivalence in education is the best matching that we can retrospectively consider. A very important difference between the ItalianCanadians and the Italians is the knowledge of a second and third language other than Italian. All Italian-Canadians, indeed, had to learn and use either French or English or both, and were continuously exposed to these languages although their mother tongue was Italian and they continued to speak fluent Italian in the family. The Italians, instead, knew and used only their mother tongue. As repeatedly reported in the literature, bilingualism is one potential factor that enhances CR and modulates the expression of neuropathology associated with AD . These authors recently reported the linear measurement of brain atrophy from the computed tomography scans of two groups of patients with probable Alzheimer’s disease: monolingual AD patients and bilingual AD patients. The two groups showed no difference in degree of clinical severity, cognitive performance and education. However, in areas traditionally recognised as damaged in AD, the bilingual patients showed significantly higher brain atrophy than the monolingual patients. This neuroanatomical difference between monolingual and bilingual individuals showed for the first time a correlation between bilingualism and the neuropathology of AD. The brain protection from dementia provided by bilingualism can be explained by the increased CR of learning a new language. However, the same authors suggest that ‘‘another possibility is that bilingual patients are often immigrants to the country of testing and that people who emigrate may have more drive than those who remain’’. Moreover, it is important to note that in the present study the instrument used to measure CR (i.e. CRIq) did not take into account the knowledge of a second language. Thus, the difference in CR of the two groups cannot be attributed to bilingualism. Rather, bilingualism often accompanies such circumstances, i.e. emigration. To be an immigrant in a new country and to acquire a new language becomes an environmental factor that favours an increased CR.
A recent meta-analysis  has shown that multiculturalism drives people to make new contacts and relationships and has a great impact on individuals’ adjustment. Contributions to cognitive reserve most likely come from multiple sources and CR changes across an individual lifespan depend on exposures and behaviour . Therefore, a comprehensive study of human cognitive neuroscience should explore the mechanisms by which cross-cultural variability creates differences in brain functions. Our study raises an important question: in which period of an individual’s lifespan do cultural changes affect brain plasticity and brain cognition? Recently, ‘‘cultural neuroscience’’  has opened new extraordinary frontiers for understanding how different cultures and changes during the lifespan can shape the brain and its functions. The present research study is novel in that it addresses CR in a cross-cultural investigation. Our study on the individual environmental changes among immigrant adults has opened a new line of research that will need to compare scientific data across different cultures and different people by taking into account the adjustments they have to face across the lifespan. Conflict of interest On behalf of all authors, the corresponding author states that there is no conflict of interest.
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