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PSYCHOGERIATRICS 2015; 15: 186–190

doi:10.1111/psyg.12093

ORIGINAL ARTICLE

Evaluating the relationship between education level and cognitive impairment with the Montreal Cognitive Assessment Test Esra YANCAR DEMIR1 and Tuba ÖZCAN2

Departments of 1Psychiatry and 2Neurology, School of Medicine, Ordu University, Ordu, Turkey Correspondence: Dr Tuba Özcan MD, Department of Neurology, School of Medicine, Ordu University, Ordu Üniversitesi Tıp Fakültesi, Nöroloji AD, Ordu 52200, Turkey. Email: [email protected] yahoo.com Received 4 July 2014; revision received 20 October 2014; accepted 28 October 2014.

Key words: cognitive impairment, education level, MoCA test.

Abstract Background: Mild cognitive impairment (MCI) is defined as ‘a cognitive decline greater than that expected for an individual’s age and education level but that does not interfere notably with activities of daily life’. The Montreal Cognitive Assessment (MoCA) is a screening test for MCI. Methods: We investigated the performance of the Turkish version of the MoCA in detecting MCI among elderly persons in a rural area, the majority of whom have a low level of education. We evaluated 50 consecutive men referred from an outpatient clinic. Educational level was divided into three categories: group 1, less than primary (5 years). We evaluated the effect of education on MoCA scores and compared subjects’ test performance among the different categories of education level. Results: A total of 50 male patients with MCI (mean age: 70.74 1 7.87) met the inclusion criteria. There were no differences in the total scores based on education or in the subscores for visuospatial/executive function, naming, attention, abstraction and delayed recall. Language was the only domain that showed significant differences between the groups. In post-hoc analysis, differences were found between groups 1 and 3 and between groups 1 and 2. Group 1 had significantly lower scores for language. The repeat subscore for language was significantly lower in group 1 than in group 2. In fluency, there were significant differences between groups 2 and 3 and between group 1 and 3. Conclusion: To our knowledge, this is the first study to analyze the applicability of the Turkish version of MoCA in populations with little education. Our results emphasize the need to adapt the language sections of this test, so it can be easily used in populations with low education levels.

INTRODUCTION Although two-thirds of all dementia cases involve patients with a low education level, most tests used to measure cognitive function were developed for people with several years of education, and performance on the tests requires the ability to read and write.1 It has been suggested that education provides a cognitive reserve through neuronal changes. The reserve hypothesis proposes that education may affect the clinical expression of Alzheimer’s disease. The cognitive reserve theory is supposed to account 186

for the disjunction between the degree of brain damage and the clinical manifestations.2 Mild cognitive impairment (MCI) is a diagnostic entity defined as ‘a cognitive decline greater than that expected for an individual’s age and education level but that does not interfere notably with activities of daily life’.3 The Montreal Cognitive Assessment (MoCA) is a screening test for MCI. The MoCA has substantial sensitivity (90%) and specificity (87%), and its subsections include tests on short-term memory recall © 2014 The Authors Psychogeriatrics © 2014 Japanese Psychogeriatric Society

Education, cognition, MoCA

(five items), visuospatial/executive function, attention, concentration, working memory, language, and orientation to time and place.4,5 The MoCA has been translated in many languages.6–8 The Japanese MoCA uses a cut-off point of 25/26 and has demonstrated a sensitivity of 93.0% and specificity of 87.0%.7 In the Korean version, a cut-off score of 22/23 was used because of the elderly’s lower education level.9 Selekler et al. used 21 as the cut-off in the Turkish version of MoCA and demonstrated that it has a sensitivity of 81.08% and specificity of 77.78%.10 We investigated the performance of the Turkish version of MoCA in detecting MCI among elderly persons in a rural area, the majority of whom have a low level of education. We evaluated the effect of education on MoCA scores and compared test performance among those with less than primary education, primary and more than primary education. The aim of this study is to evaluate the Turkish version of MoCA’s ability to assess cognitive impairment across education levels.

MATERIALS AND METHODS We evaluated 50 consecutive men referred from the Neurology and Psychiatry Outpatient Clinic at Ordu University Training and Research Hospital who fulfilled the following inclusion criteria: were aged 60 and older; had subjective complaints of mild memory impairment; and had no impairment in daily functioning. Clinical diagnostic interviews were conducted by a psychiatrist. The diagnostic criteria for MCI were defined as follows: global cognitive function was consistent with normal cognition; the patient complained of memory deterioration, or his relatives and doctors thought he had memory impairment; the duration of the memory impairment symptoms was less than 3 months; activities of daily living and social function were declining; and Diagnostic and Statistical Manual of Mental Disorder, fourth edition, criteria for the diagnosis of dementia were not met.3 Patients with other neurodegenerative

diseases, depression, metabolic disorders, endocrine disorders, cerebrovascular diseases, epilepsy, and hepatic, renal, or hematopoietic diseases were also excluded. This study was approved by the local ethics committee of Ordu University. Educational level was divided into three categories: group 1, less than primary (5 years). Statistical analyses were performed using SPSS version 20.0 (IBM, Istanbul, Turkey). Continuous variables were expressed as mean 1 SD, and categorical variables were expressed as frequencies. ANOVA and Kruskal–Wallis tests were used to evaluate differences in patients’ characteristics. Statistical significance was considered for P-values less than 0.05.

RESULTS A total of 50 patients with MCI (mean age: 70.74 1 7.87) met the inclusion criteria. Age differences between the three education levels are shown in Table 1. There were no illiterate subjects. Group 1 (less than primary (5 years)) had 15 subject (30%). Overall MoCA total scores and subscores are shown in Table 2, and total scores and subscores according to education level are shown in Table 3. The mean MoCA score in the total population was 18.2 1 4.02. Mean scores were 17.16 1 3.78, 18.0 1 4.50, and 19.73 1 3.56 for groups 1, 2, and group 3, respectively. There were no differences in the total scores based on education or in the subscores for visuospatial/ executive function, naming, attention, abstraction and delayed recall. Language was the only domain that showed significant differences between groups. In post-hoc analysis, differences were found between groups 1 and 3 and between group 1 and 2. Group 1 had significantly lower scores for language. The repeat subscore of language was significantly lower in group 1 than in group 2. In fluency, there were significant differences between groups 2 and 3 and

Table 1 Characteristics of the study sample (n = 50)

Mean age (years) MCI

Less than primary (n = 19 (38%))

Primary (n = 16 (32%))

More than primary (n = 15 (30%))

P-value

69.89 1 8.33 15 (30%)

69.75 1 8.20 11 (22%)

70.74 1 7.87 7 (14%)

0.466 0.137

MCI, mild cognitive impairment.

© 2014 The Authors Psychogeriatrics © 2014 Japanese Psychogeriatric Society

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between groups 1 and 3. Delayed recall was very poor in all education groups: 0.68 1 1.25 words out of five words were recalled in group 1, 0.88 1 1.15 in group 2, and 0.92 1 1.21 in group 3.

DISCUSSION In this study, we analyzed the ability of the MoCA to assess cognition. Based on the MoCA, the prevalence of MCI was high, with more than half of subjects (66%) screening positive for MCI. Our main finding is that the Turkish version of MoCA is not associated with education level except with regard to language. To understand the reality of cognitive reserve theory, we used MoCA to investigate educational difTable 2 MoCA total score and subscores of all patients (n = 50) All patients MoCA total score Visiospatial/executive Trail making Cube Clock drawing Naming Attention Digits Letters Serial subtraction Language Repeat Fluency Abstraction Delayed recall

18.2 2.32 0.30 0.56 1.46 2.70 4.1 1.62 0.80 1.66 1.30 1.00 0.30 1.18 0.92

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

4.02 1.56 0.46 0.50 1.07 0.54 1.69 0.56 0.40 1.20 0.74 0.60 0.46 0.82 1.21

ferences in patients with MCI and without systemic diseases, cerebrovascular disease, hypertension, or other vascular risk factors. MoCA test scores were not influenced by education. This is in contrast to another study that indicated that the MoCA’s educational bias needs to be resolved if the test is to be used in populations with low education levels.11,12 Rossetti et al. recommended caution when applying cut-off points based on normative data from populations that differ from the one for which the MoCA was developed because of the high failure rate of specific items in the test.12 In addition, Bernstein et al. showed that the recommended 1-point education correction correlates negatively with the total score and, as a consequence, impairs reliability.11 Results of previous studies examining the relationship between education level and cognition have not been consistent. In a prospective community survey in old subjects, education was found to be associated with level of cognitive function but not with the rate of cognitive decline.13 Fujiwara et al. reported that the Mini-Trail Making Test B and digit span were significantly correlated with school years among normal controls.7 In the present study, language scores significantly differed between the groups, indicating that scores were influenced by education. This suggests that an increase in educational level reduced the effectiveness of MoCA’s language domain, especially fluency. Partly similar to our study, an earlier large cohort study showed that education was strongly

MoCA, Montreal Cognitive Assessment.

Table 3 MoCA total score and subsections by education (n = 50)

MoCA total score Visiospatial/executive Trail making Cube Clock drawing Naming Attention Digits Letters Serial subtraction Language Repeat Fluency Abstraction Delayed recall Orientation

Less than primary (n = 19 (38%))

Primary (n = 16 (32%))

More than primary (n = 15 (30%))

P-value

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

18.0 1 4.50 2.19 1 1.18 0.31 1 0.48 0.63 1 0.050 1.25 1 1.00 2.62 1 0.50 3.94 1 1.57 1.50 1 0.63 0.88 1 0.34 1.56 1 1.21 1.38 1 0.72 1.25 1 0.68 0.13 1 0.34 1.19 1 0.91 0.88 1 1.15 5.50 1 1.03

19.73 1 3.56 2.20 1 1.66 0.20 1 0.41 0.47 1 0.52 1.53 1 1.13 2.67 1 0.62 4.67 1 1.72 1.80 1 0.41 0.87 1 0.35 2.0 1 1.25 1.80 1 0.68 1.07 1 0.46 0.73 1 0.46 1.18 1 0.83 0.92 1 1.21 5.87 1 0.35

0.176 0.771 0.579 0.674 0.642 0.655 0.297 0.319 0.289 0.425 0.000ab 0.036b 0.000ac 0.381 0.380 0.395

17.16 2.53 0.37 0.58 1.58 2.79 3.79 1.58 0.68 1.47 0.84 0.74 0.11 1.00 0.68 5.53

3.78 1.68 0.49 0.51 1.12 0.54 1.75 0.61 0.48 1.17 0.50 0.56 0.32 0.75 1.25 0.90

a Significant difference between groups 1 and 3. bSignificant difference between groups 1 and 2. cSignificant difference between groups 2 and 3. MoCA, Montreal Cognitive Assessment.

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© 2014 The Authors Psychogeriatrics © 2014 Japanese Psychogeriatric Society

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related to cognitive level in all domains, particularly verbal fluency.14 Karrasch and Laine reported that the naming, verbal fluency, and verbal memory tests were affected by education.15 Lièvre et al. concluded that the development of cognitive impairment was highly affected by education.16 It is not clear which mechanisms are linked to the association between education and cognitive functions. Previous studies have shown that a low education level is a risk factor for cognitive impairment in older age,17–19 and it has been noted that MoCA cognitive domains reflect an educational gradient, including some form of language that might be primarily developed through schooling.9 Several mechanisms have been suggested to explain the relationship between education and cognition. It has been suggested that education may be a marker of other factors associated with cognition. Also, lower brain reserve may be related to low education.18 Snowdon et al. found a relationship between early life linguistic ability and density of neurofibrillary tangles.20 Some studies have found that education level does not directly affect the Alzheimer’s disease pathology and instead can postpone the onset of the symptoms.21,22 Some authors have suggested that better task performance related with higher education might be masking the clinical expression of the degree of neurodegeneration.22–24 Garibotto et al. showed an association between higher education and a lower regional cerebral metabolic rate of glucose consumption in the posterior temporoparietal cortex and precuneus in Alzheimer’s disease and MCI.25 Our findings provide information on the relationship between education and performance on MoCA with regard to assessing cognition in populations with low education levels. Our study had several limitations. The sample size was small so the findings from this study cannot be generalized to the whole population of Turkey. To our knowledge, this is the first study to analyze the applicability of the Turkish version of MoCA in populations with little education. Our results emphasize the need to adapt the language sections of this test, so it can be easily used in populations with low education levels.

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© 2014 The Authors Psychogeriatrics © 2014 Japanese Psychogeriatric Society

2 Stern Y. Cognitive reserve. Neuropsychologia 2009; 47: 2015– 2028. 3 Gauthier S, Reisberg B, Zaudig M et al. Mild cognitive impairment. Lancet 2006; 367: 1262–1270. 4 Nasreddine ZS, Phillips NA, Bedirian V et al. The Montreal Cognitive Assessment, MoCA: a brief screening tool for mild cognitive impairment. J Am Geriatr Soc 2005; 53: 695–699. 5 Damian AM, Jacobson SA, Hentz JG et al. The Montreal Cognitive Assessment and the mini-mental state examination as screening instruments for cognitive impairment: item analyses and threshold scores. Dement Geriatr Cogn Disord 2011; 31: 126–131. 6 Rahman TT, El Gaafary MM. Montreal Cognitive Assessment Arabic version: reliability and validity prevalence of mild cognitive impairment among elderly attending geriatric clubs in Cairo. Geriatr Gerontol Int 2009; 9: 54–61. 7 Fujiwara Y, Suzuki H, Yasunaga M et al. Brief screening tool for mild cognitive impairment in older Japanese: validation of the Japanese version of the Montreal Cognitive Assessment. Geriatr Gerontol Int 2010; 10: 225–232. 8 Tsai CF, Lee WJ, Wang SJ et al. Psychometrics of the Montreal Cognitive Assessment (MoCA) and its subscales: validation of the Taiwanese version of the MoCA and an item response theory analysis. Int Psychogeriatr 2012; 24: 651–658. 9 Lee JY, Lee DW, Cho SJ et al. Brief screening for mild cognitive impairment in elderly outpatient clinic: validation of the Korean version of the Montreal Cognitive Assessment. J Geriatr Psychiatry Neurol 2008; 21: 104–110. 10 Selekler K, Cangöz B, Uluç S. Montreal Bilis¸sel Deg˘erlendirme Ölçeg˘i (MOBI˙D)’nin hafif bilis¸sel bozukluk ve Alzheimer hastalarını ayırt edebilme gücünün incelenmesi. Turk J Geriatr 2010; 13: 166–171. 11 Bernstein IH, Lacritz L, Barlow CE, Weiner MF, Defina LF. Psychometric evaluation of the Montreal Cognitive Assessment (MoCA) in three diverse samples. Clin Neuropsychol 2011; 25: 119–126. 12 Rossetti HC, Lacritz LH, Cullum CM, Weiner MF. Normative data for the Montreal Cognitive Assessment (MoCA) in a population-based sample. Neurology 2011; 77: 1272–1275. 13 Tasha S, Nadia G, Clive H. The Montreal Cognitive Assessment: validity and utility in a memory clinic setting. Can J Psychiatry 2007; 52: 329–332. 14 Zahodne LB, Glymour MM, Sparks C et al. Education does not slow cognitive decline with aging: 12-year evidence from the Victoria Longitudinal Study. J Int Neuropsychol Soc 2011; 17: 1039–1046. 15 Karrasch M, Laine M. Age, education and test performance on the Finnish CERAD. Acta Neurol Scand 2003; 108: 97–101. 16 Lièvre A, Alley D, Crimmins EM. Educational differentials in life expectancy with cognitive impairment among the elderly in the United States. J Aging Health 2008; 20: 456–477. 17 Seeman TE, Huang MH, Bretsky P et al. Education and APOE-e4 in longitudinal cognitive decline: MacArthur Studies of Successful Aging. J Gerontol B Psychol Sci Soc Sci 2005; 60: 74–83. 18 Fratiglioni L, Wang HX. Brain reserve hypothesis in dementia. J Alzheimers Dis 2007; 12: 11–22. 19 Barnes DE, Yaffe K. The projected effect of risk factor reduction on Alzheimer’s disease prevalence. Lancet Neurol 2011; 10: 819–828. 20 Snowdon D, Kemper S, Mortimer JA et al. Linguistic ability in early life and cognitive function and Alzheimer’s disease in late life. JAMA 1996; 275: 528–532.

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© 2014 The Authors Psychogeriatrics © 2014 Japanese Psychogeriatric Society

Evaluating the relationship between education level and cognitive impairment with the Montreal Cognitive Assessment Test.

Mild cognitive impairment (MCI) is defined as 'a cognitive decline greater than that expected for an individual's age and education level but that doe...
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