Assessing memory clinic patients and healthy controls with a low educated, non-Western background on the performance on a neuropsychological test battery
Fatma Gul Karagoz 11447567
Psychobiology, University of Amsterdam
Supervisor: S. Franzen Bachelor Thesis
Abstract
The prevalence of dementia disorders is increasing and this is mostly attributed to the rise of dementia patients with a non-Western background. Despite this increase, neuropsychological test batteries are not always appropriate to these populations due to a lack of research.
This study aimed to examine the diagnostic accuracy of a recently developed
neuropsychological test battery in non-Western immigrants with low levels of education. Fifty-five dementia patients and forty-nine healthy controls were assessed using an
experimental test battery. The test battery covers multiple cognitive domains such as memory, language, attention, executive functioning, and visuospatial functions. The results showed significance in all test instruments that were included in the test battery, except for the naming part in the Recall of the Pictures test and the Coin in the hand test. It can be concluded that evidence has been found for a difference between memory clinic patients and controls without cognitive impairments in the performance on the neuropsychological test battery. This
suggests that the test battery can be used to research non-Western immigrants in a
neuropsychological assessment for dementia. Future research should focus on reducing the administration time of the test battery by examining valid, shorter tests. This can be obtained by shortening test instruments by only using sensitive items.
Keywords: Dementia disorders, non-Western immigrants, education, diagnostic
Introduction
Dementia is a (progressive) condition in which cognitive function degenerates beyond what one might expect from normal aging. It impairs multiple cognitive domains, such as memory, orientation, and language. Additionally, it is often accompanied by a deterioration of social behavior and emotional control (World Health Organization, 2019).
Worldwide, around 50 million people suffer from dementia and it is expected that this number will triple in 2050. This rise can be largely explained by the increasing numbers of people with dementia in developing countries (World Health Organization, 2019). For instance, due to improvements in life expectancy, non-Western populations reach an age where dementia is more frequent. This also applies to non-Western minorities living in Western countries (Franzen et al., 2019). A study, which was conducted in the Netherlands, indicated that the prevalence of dementia in non-Western immigrants, such as Turkish and Moroccan minorities, was three to four times higher compared to native residents in the Netherlands (Parlevliet et al., 2016). This is in line with other studies that have shown that the prevalence of dementia in non-Western immigrants is more than twice as high compared to native citizens in Western countries (Adelman et al., 2011; Fitzpatrick et al., 2004).
The high dementia prevalence numbers in non-Western immigrants can be explained by multiple factors. First, living in rural areas from an early age has been associated with Alzheimer’s disease (AD) (Russ et al., 2012). This can be explained by the exposure to harsh conditions in rural life that can occur, such as malnutrition and harm by pesticides (Parlevliet et al., 2016). Second, migration itself has been indicated with depression which can be caused by racial discrimination and acculturative stress (Aichberger et al., 2010). In addition,
psychiatric illnesses like depression have been associated as a cause of higher dementia prevalence in non-Western immigrants (Bindraban et al., 2008). Moreover, having low or no education and a lower socioeconomic status (SES), and thus little cognitive reserve, could
also be a factor in the higher prevalence of dementia of immigrants (Sattler et al., 2012). Lastly, Uitewaal et al. (2004) indicated that in the Netherlands, cardiovascular diseases, such as type 2 diabetes mellitus, are more prevalent in non-Western residents and also occur at a younger age in comparison to native Dutch residents. Consequently, since these conditions are a major cause for dementia, this may be more frequent and may occur earlier in
immigrants (Gorelick et al., 2011).
The available neuropsychological tests used to evaluate dementia are well-established and fundamental to an accurate diagnosis (Franzen et al., 2019). However, these tests rely heavily on Western linguistic, cultural, and educational elements. As a result, assessing non-Western immigrants will often lead to a misleading or invalid outcome (Nielsen, Andersen, Kastrup, Phung, & Waldemar, 2011). Moreover, this phenomenon is strongly prevalent when examining elderly immigrants, as they are often low-educated or illiterate (Lindesay, 1998; Schellingerhout, 2004). For instance, elderly people who are 60 years and older receive significantly fewer dementia diagnoses compared to native residents. In contrast, people under the age of 60 are often over-diagnosed (Nielsen, Vogel, Phung, Gade, & Waldemar, 2011).
Literacy is an important factor when assessing cognitive tests, as it has been shown that being illiterate significantly affects one’s performance (Ardila et al., 2010). For example, one study showed that literacy affected multiple abilities, such as phonological skills,
visuospatial abilities, and executive functions. As a consequence, illiterate subjects frequently performed worse on tasks, including comprehension, naming, recognition of figures, and comprehension tasks (Manly et al., 1999).
Obtaining a misdiagnosis due to unsuitable neuropsychological tests for ethnically diverse elders can cause unnecessary stress and confusion for people who don’t have the disease but still got diagnosed. The same goes for people who do have the disease but are told
they do not, causing a delay in treatment and care (Goudsmit et al., 2018). Hence, it is of importance that valid cross-cultural tests are used when evaluating dementia.
Concerning Western tests and their accessibility rate to foreigners, multiple studies have been conducted in which cognitive test batteries were evaluated. The Consortium to Establish Registry for Alzheimer’s Disease (CERAD) battery was developed to create global consistency in the assessment methods of Alzheimer’s disease (AD) (Morris, Mohs, Rogers, Fillenbaum, & Heyman, 1989). The battery consists of several instruments, such as the Constructional Praxis test, the Boston Naming test (15 items), and Verbal Fluency (animals). A study that developed a Korean version of the CERAD battery indicated difficulty regarding some of the test instruments. For instance, mental imagery and phonemic similarity were perceived as difficult by some Korean subjects. In addition, a suitable translation was found to be not possible in certain cases (Lee et al., 2002). In contrast to the CERAD battery, Nielsen et al. 2018 developed the Cross-Cultural Neuropsychological Test Battery (CNTB) which had more promising results. Along with the assessment of AD, this battery also evaluates other dementia disorders in multicultural populations. Moreover, instruments such as the Clock reading test, verbal fluency (food and animals), and Rowland Universal Dementia assessment scale (RUDAS) are included. The results of the study indicated that this test battery was suitable for various minority and majority populations in Western Europe and normative data was shown (Nielsen et al., 2018).
Franzen et al. (2019) published a review that provided an insight into various test batteries and instruments and their accessibility to non-Western immigrants and thus
evaluating their cross-cultural potential. While this review gives more clarity on this matter, it also highlights that current studies haven’t included all Western countries and their non-Western residents. This implies that more research is needed as non-non-Western immigrants all over the Western world differ.
This is also evident in the Netherlands, where there has been insufficient research into the (different) cognitive performance of cognitively intact immigrants and immigrants with dementia. As a result, norms for test batteries are lacking, which negatively affects the neuropsychological assessment of non-Western immigrants (Elbulok-Charcape, Rabin, Spadaccini, & Barr, 2014).
This study could therefore give us more insight into the cognitive abilities of non-Western migrants in the Netherlands. Additionally, studying more immigrants with and without cognitive complaints would be a good step in obtaining valid test norms as this will lead to an improvement in evaluating dementia in literate and illiterate immigrants.
This study aims to research how a recently constructed experimental test battery of the TULIPA project will perform when assessing dementia in memory clinic patients. This is of interest since there is no (European) consensus on which test battery is suitable for non-Western immigrants with low levels or no education. Therefore, it is necessary to examine whether there is a difference between memory clinic patients and healthy controls with a low educated, non-Western background in the performance on a neuropsychological test battery. It is hypothesized that healthy controls will perform better on the test battery compared to memory clinic patients.
To investigate this, subjects are asked to complete a neuropsychological test battery. The test battery consists of instruments that cover multiple cognitive domains: (1) language, (2) memory, (3) visuospatial functions, (4) executive functions, (5) global cognitive functions, and (6) attention. Furthermore, it is expected that the group containing cognitively intact controls will obtain a higher score on the tests in the test battery compared to the group with dementia.
Methods Participants
Non-Western individuals without cognitive complaints were assessed using multiple neuropsychological tests from the experimental test battery. Forty-nine subjects were included as the control group, twenty-six of which were previously assessed by another research
student. The other twenty-three controls were added in the current study. The sample
consisted of thirty-three females and sixteen males, both with low or no education levels, and their ages varied between 54 and 83 years. The inclusion criteria for the control group were: (A) age> 53, (B) no self-reported cognitive complaints, (C) a RUDAS score ≥ 22, and (D) a Geriatric Depression Scale (GDS-15) score of <6. Four controls were excluded due to high GDS scores in this study. The remaining forty-nine subjects reported no cognitive complaints and had normal hearing and normal to corrected-to-normal vision. All subjects gave informed consent.
Patient data of the multicultural memory clinic at the Alzheimer Center was used, which were collected in the outpatient multicultural memory clinics of the Erasmus MC University Medical Center, Maasstadziekenhuis, and MC Haaglanden. In total, 55 non-Western immigrant patients were clinically evaluated by a geriatrician or neurologist, using a neuropsychological assessment (test battery), laboratory screening with blood tests, and (in a subset of patients) structural brain imaging (CT or MRI scan). Patients were between 45 and 89 years old and consisted of twenty-six females. Furthermore, patients were diagnosed using the diagnostic research criteria for dementia subtypes (Mckhann et al., 2011; Roman et al., 1993; Albert et al., 2011). Only patients with a dementia diagnosis were included in this study.
Test battery
The test battery consists of several tests of the CNTB, developed by Nielsen et al. (2018), along with other newly developed tests and questionnaires. Table 1 illustrates which test instruments are included in the test battery and which cognitive domains the instruments cover. The Cross-Cultural Dementiascreening (CCD) is a screening test that covers attention, mental speed, and executive functioning and is part of the golden standard. This test
instrument was included in the assessment of the dementia group, but not for the control group and is therefore not mentioned in Table 1.
It is of importance that the various tests meet the following criteria: (1) the tests are cross-cultural, (2) the tests are applicable for assessment of cognitive impairments in various types of dementia, (3) the tests can be used with people with low or no education levels, (4) the tests can be carried out with an interpreter in a straightforward way (Nielsen et al., 2018). Furthermore, the instructions in the test battery were translated into the language the subjects preferred.
Table 1.
Description of the test battery and its instruments.
Item Test instruments Description Cognitive domain(s)
Golden standard 1. Rowland Universal
Dementia Assessment Scale (RUDAS) (Storey et al., 2004). *
2. Fluency (Strauss et al., 2006). *
3. Modified VAT (Franzen et al., 2019).
1. Multi-cultural cognitive screening test
2. Consists of animal and food items
3. Short test that measures anterograde amnesia 1. Visuoconstruction; memory; language; judgment; praxis; visuospatial orientation 2. Language; executive functions 3. Memory
Screening for illiteracy 4. Measures literacy on three
levels: phonological awareness, receptive language, and language production.
4. Basic literacy skills (language)
Battery for illiterate patients 5. Recall of Pictures Test (Nielsen et al., 2012). * 6. Clock Reading Test (Schmidtke & Olbrich, 2007). *
7. Five Digit Test (Sedo, 2007). *
8. Stick Design test (Baiyewu et al., 2005). 9. Corsi-Block Tapping Test (Corsi, 1972). 10. Experimental Cross-Cultural Naming Test (pilot version).
11. Coin-in-the-Hand Test (Kapur, 1994).
5. Learn and remember ten pictures on three learning trials; instant recall after viewing the images, after a ten-minute interval free recall, and lastly recognition after viewing the original and newly added images.
6. Indicate which time it is on pre-printed analog clock faces. 7. Tell how many or which numbers can be seen depending on the instruction
8. Recreate a pre-printed design with four matches.
9. Following and tapping a sequence that occurs on the blocks.
10. Naming images that consist of sixty items.
11. Measuring performance validity by asking in which closed hand the coin is.
5. Memory 6. Visuospatial functions 7. Mental speed; executive functions; attention 8. Visuoconstruction 9. Memory; Attention span 10. Language 11. Attention
Additional tests for literate patients
12. Stroop (Karakas et al., 1999).
12. Naming colors while ignoring the words or naming words while ignoring the colors depending on the item.
12. Mental speed; executive functions; attention
Questionnaires 13. GDS (Sheikh &
Yesavage, 1986). 14. SASH
13. Indicates presence of depression
14. Indicates acculturation level Note. * = part of CNTB.
Procedure
Subjects were asked to complete an approximately 90-minute test battery, which included the tests and questionnaires in Table 1. Figure 1 illustrates how two test instruments are displayed. Moreover, subjects were assessed by a Psychobiology student and an
interpreter in their primary language. The instruments were conducted in the same order, but it had to be taken into account that there had to be 10 minutes between the immediate and delayed recall of the Recall of pictures test, so there would be no interference. This means that some tests between the two items could be shifted to maintain the 10-minute interval.
Moreover, there were two versions of the modified VAT; a long version for subjects under 65 years and a short version for subjects above this age.
Furthermore, the tests were conducted at the hospital (patients), the community center (controls), or in the homes of the participants (controls). In order to maintain the same
conditions at different locations, disruptive factors (i.e. background noise, different lighting) were minimized during testing.
Figure A1. Example of the Clock reading test.
Statistical analysis
The independent variable was the group consisting of dementia patients versus the healthy controls. The dependent variable was the obtained scores on the various tests. The study was a between-subject design as the two different groups are being compared. RStudio version 3.5.3 was used to perform an independent t-test. The nonparametric Mann-Whitney U test was performed as the assumption of normality was violated for all of the variables of the control group and most of the variables in de memory clinic group.
Results
Table 2 indicates that most of the demographic characteristics of the patient group and the control group are not equal as the p-values are significant. However, the time that was spent in the Netherlands was not significant and thus equal in both groups. Because the control group showed significance when using the Shapiro-Wilk test, the assumption of normality was not met. As a result, the Mann-Whitney U test was used. When performing analysis for Gender, Chi-squared test was used as it is a nominal variable. The assumption for normality was also not met case when statistical analysis was performed on the individual test instruments (Table 3). Here, all test instruments showed significance between the patient group and control group, except for the Coin in the Hand Test (W=4, p=0.16) and the naming item in Recall of Pictures Test (W=236, p=0.79).
Table 2.
Demographic characteristics of the memory clinic group (patients) and the control group.
Patients (n=55) Controls (n=49) Statistical test
Age 77.00 (8.00) N= 51 59.00 (8.75) N= 46 W=2255, p<0.01 Education - 0 years of education - 1 year up to prim. Education - >prim. Education 32% 44% 24% 8% 50% 42% W=911, p<0.01 Gender, male % 53% 33% W=1077, p=0.04
Time in the Netherlands in years
46.00 (17.00) 44.00 (9.00) W=1165, p=0.52
Note. Values are displayed as median (IQR) or percentages.
Table 3.
Results of the performance on the test battery.
Patients (n=55) Controls (n=49) Statistical test
Rudas 17.00 (6.50) 28.00 (2.00) W=44.5, p<0.01
Fluency food 9.00 (4.00)a 22.00 (7.00) W=17.5, p<0.01
Fluency animals 7.00 (4.00) 19.00 (7.00) W=39, p<0.01
Modified vat long version - 17.50 (5.00) -
Modified vat short version 2.00 (5.50) 12.00 (1.00) W=9, p<0.01
Screener for illiteracy 10.00 (2.50)b 14.00 (1.00) W=24, p<0.01
Recall of pictures test
- Naming - Incidental - Immediate - Delayed - Recognition 10 (0) 2(3) 4 (1) 1 (3) 6 (3) 10 (0) 9 (4) 9.5 (1.5) 9 (2) 10 (0) W=236, p=0.79 W=24.5, p<0.01 W=337, p=0.04 W=1.5, p<0.01 W=38, p<0.01
Clock reading test 6.5 (4.5) 12 (1) W=4, p<0.01
Five Digits test
- Reading (sec) - Counting (sec) - Choosing (sec) - Shifting (sec) 63 (31) 58 (8) 93 (59.75) 88 (23) 28 (12.5) 29 (10.5) 54 (18.5) 69 (17) W=318, p<0.01 W=307, p<0.01 W=272, p<0.01 W=123.5, p=0.03
Stick design test 11 (1.25) 12 (0) W=40.5, p<0.01
Corsi-block test - Forward - Backward 12 (16)c 4 (0.5)c 35 (16) 24 (15) W=69.5, p<0.01 W=14.5, p<0.01 Naming Test 53 (4)d 58 (3)e W=17.5, p<0.01
Coin in the hand test 10 (1) 10 (0) W=173.5, p=0.16
Stroop test (sec) - 102.5 (36.025) -
Note. Values are displayed as median (IQR). an= 17 patients. bn= 7 patients. cn= 8 patients. dn= 9 patients. en= 23 patients.
Discussion
In this study, the validity of the newly developed test battery of the TULIPA project was investigated. Based on the results, it can be concluded that evidence has been found for a difference between memory clinic patients and healthy controls with a low educated, non-Western background in the performance on the neuropsychological test battery. This corresponds with Nielsen et al. (2018), in which the CNTB was found appropriate for non-Western minority populations living in non-Western Europe. In addition to the CNTB, the significance of the remaining test instruments of the test battery indicates that there is a
difference in performance between both groups. This finding is in line with earlier studies that found that these instruments were appropriate to diverse individuals (Ardila, 2007; Baiyewu et al., 2005; Corsi, 1972; Franzen et al., 2019). Finding evidence concerning the test
instruments suggests that individuals without cognitive complaints can comprehend the test instructions (i.e. no language barriers), and the instruments itself are appropriate as it doesn’t rely on Western properties. This indicates that the test battery can be used as a tool to examine non-Western immigrants in a neuropsychological assessment for dementia.
The Coin in the Hand Test was designed to detect simulation or exaggeration of psychological symptoms among amnestic patients (Kapur, 1994). Not finding a significance in the Coin in the Hand test therefore suggest that no malingering was present in both groups. Second, the naming item of the Recall of Pictures Test also shows insignificance, which implies that there is a ceiling effect in both the control group as the dementia group; almost all subjects obtained the maximum score, which makes it difficult to discriminate between the two groups. Furthermore, the Screener of Literacy shows significance which means that the literacy in both groups is not equal. This could imply that the dementia group may have performed worse on test instruments simply because they are not nearly as literate as the control group. However, their dementia diagnosis may be a prominent factor in their
performance as a study found that dementia patients scored lower on reading and writing in a standard aphasia test battery compared to a control group (Murdoch, Chenery, Wilks, & Boyle, 1987). Concerning the results of the demographic characteristics, the significance can be explained by the relatively young control group compared to the dementia group. In addition to the age gap, younger generations are generally able to pursue more education than older generations in ethnic populations and this difference can be seen in Table 2 regarding the levels of education (Fry & Parker, 2018). As most demographic characteristics are significant among the two groups, hard statements cannot be made to what extent the results correctly align with the hypotheses made in this study. However, due to the current pandemic, finding controls that shared similarity by age and education with the patient group was
limited.
Other limitations that occurred during the study must be also taken into consideration. First, the locations that were used to assess the test battery were not always optimal (i.e. homes of the controls). Although we tried the minimize background noise, the controls sometimes got distracted by their spouses or cell phones, even though we indicated that it had to be completely silent. Second, the administration time of the test battery caused (slight) frustration among some controls. This resulted in less focus during the ends of the test battery, which could have affected their performances. Lastly, data of the Stroop task and the long version of the mVAT were absent in the patient group, so statistical analysis couldn’t be performed. As a result, no indication can be given regarding the accessibility of these tests to non-Western immigrants in this study.
For future research, it would be interesting to examine to what extent the experimental test battery assesses various dementia disorders. Nielsen et al. (2018) found that the
assessment of CNTB resulted in distinct patterns of cognitive impairment in patients with AD and patients with non-AD dementia. Hence, the current test battery may also contribute to this
cognitive distinction. As mentioned earlier, finding a significance in demographic
characteristics can be prevented by simply matching the two groups by age, education, and gender. Thus, the obtained results will have more validity. Lastly, as the test battery lasts about 90 minutes, it is important to research alternative tests that take less time and still ensure a good assessment. In this way, it can be prevented that the subjects, and certainly the elderly, become fatigued (mentally). This can be achieved by shortening the Five Digit Test for example, by only using the most sensitive items. The Five Digit Test consists of multiple items with distinct levels of difficulty and examining which items give the most correct indication of cognitive impairment and thus have high sensitivity should be included in the instrument. Because a cognitive domain is covered by at least two test instruments, shortened tests still can ensure that low performance is solely based on cognitive impairments on a specific cognitive domain and not because of distractions or nervousness.
Gaining knowledge about neuropsychological tests and their accessibility to minorities is of importance to prevent misdiagnoses of dementia disorders. This can prevent unnecessary stress for the patients and their caregivers, and a potential delay in treatment. Also, more research can cause more awareness to health care professionals as they can gain better knowledge in treating non-Western patients, especially if the patients have low levels of education.
Overall, the neuropsychological test battery that is developed in the TULIPA project is appropriate to non-Western immigrants and is valid to evaluate dementia. In addition, more research could strengthen this validity, in which ultimately the neuropsychological battery can be applied all over the Western world and even in the non-Western world.
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