Adaptation and Validation of the Tamil (Sri Lanka) Version of the Montreal Cognitive Assessment (MOCA)

The study aimed to develop the Tamil (Sri Lanka) version of the Montreal Cognitive Assessment (MoCA) and investigate its reliability and validity as a brief screening tool for mild cognitive impairment (MCI). Tamil-speaking Sri Lankan older adults with normal cognition and MCI were recruited from a neurology clinic. Adaptation of the English MoCA to the Tamil (Sri Lanka) involved contextspecific content modification and translation. The content validity, reliability, sensitivity, and specificity of the tool were evaluated. Study participants were 184 older adults, comprising 85 with normal cognition and 99 neurologist-diagnosed MCI. The tool had high internal consistency (Cronbach's alpha=0.83). ROC curve analyses showed an area under the curve of 0.87 (95% CI 0.83-0.91) for detecting MCI. The optimal cut-off score for detection of MCI was 23/24, yielded a sensitivity and specificity of 84.7% and 76.4%, respectively. The Tamil (Sri Lankan) version of the MoCA maintains its core diagnostic properties rendering 1 Department of Community and Family Medicine, Faculty of Medicine, University of Jaffna, Sri Lanka, padcoonghe@univ.jfn.ac.lk 2 No. 26 D 1/1, Rosmed Place, Colombo 7, Sri Lanka. 3 Psychiatry Unit, Teaching Hospital, Jaffna, Sri Lanka. 4 Neurology Unit, Teaching Hospital, Jaffna, Sri Lanka. 5 Duke-National University of Singapore (NUS) Medical School No.8, College Road, Singapore 169857. 6 Duke Global Health Institute, No.310, Trent Drive, Durham NC USA, 27710. Date Received: 22 October 2018 Date Accepted: 19 December 2019 KALYĀNĪ: Journal of the University of Kelaniya, ISSN 2012-6859, Volume XXXIII (Issue I/II), 2019 2 it a valid and reliable tool for screening of MCI among Tamil speaking Sri Lankan older adults.


Introduction
Mild cognitive impairment (MCI) refers to an intermediate transitional cognitive phase between cognition of normal aging and mild dementia. Individuals with MCI carry a high risk of deterioration to Alzheimer's disease (AD) and other dementias relative to cognitively normal individuals. In 2005, the Montreal Cognitive Assessment (MoCA) (Nasreddine et al., 2005) was reported to be a better screening test for MCI than the Mini-Mental State Examination (MMSE) (Folstein, Folstein, & McHugh, 1975) among English and Frenchspeaking persons. While the MoCA had a sensitivity and specificity of 90% and 87%, respectively for detecting MCI, the MMSE, which is widely used by primary care physicians to screen for dementia, had a sensitivity of only 18% for MCI (Nasreddine et al., 2005). Consequently, the use of the MoCA for screening for MCI has become pervasive in many countries. At the same time translation and validation studies of the MoCA have confirmed its validity as a screening test for MCI in several countries, including South Korea, China and Sri Lanka (Lee et al., 2008, Yeung et al, 2014, Karunaratne et al, 2011. In Sri Lanka, except for Sinhala language version of the MoCA (Karunaratne et al., 2011) the Tamil language version has not been validated. Sri Lanka has a population of about 21million (Department of Census and Statistics, 2012). Sinhala and Tamil are the major languages spoken in the country with Tamil beins spoken by about 5 million individuals. Globally, Tamil is spoken by 75.8 million people, an official language in three countries (India, Sri Lanka, and Singapore) and is also common in Australia, Canada, Malaysia, Mauritius, and Burma. At the same time, many dialects of the spoken Tamil language, which vary from each other, are used in different geographical regions of the world (Simons & Fennig, 2018). Such variations exist across regions in close geographical proximity; for instance, the vocabulary and grammar used by the

Participants
This was a cross-sectional study of ambulatory, community-dwelling, Tamil

Instrument
The MoCA is a one-page instrument. It measures eight cognitive domains with 10 items, and includes tests on short-term memory recall, visuospatial abilities, multiple aspects of executive functions, phonemic verbal fluency, abstraction, attention, concentration and working memory, language function, and time and place orientation (http://www.mocatest.org). The MoCA can usually be completed in 10 minutes. In the original English and French MoCA version, one point is added for individuals with 12 or fewer years of education. The highest possible score is 30 points, and a higher score is indicative of better cognitive status.
We obtained permission to use the MoCA from its developer (Nasreddine et al., 2005). The original English version of the MoCA was first translated into (Sri Lanka) Tamil by three bilingual Tamil-speaking Sri Lankan medical professionals (Community Physician, Psychiatrist and Neurologist) separately, and the final version was approved with the consensus of all the experts who participated in the translation. Subsequently, this version was back-translated into English by a native Tamil speaker who was unfamiliar with the English version of the MoCA.
Finalizing the Sri Lanka Tamil version of MoCA, the following linguistic and cultural adaptations were made.
(1) Trail making test: The first five letters of the English alphabet were replaced with the first five letters of the Tamil Alphabet.
(2) Naming test: Pictures of a rhinoceros, and a camel were replaced with pictures of an elephant and a cow as the local community is more familiar with the latter animals than the former.
(3) Memory test: While two (face and red) of the five original words were retained, the rest (velvet, church, and daisy) were replaced. 'Velvet' was replaced with the Tamil word for 'Silk' as silk is a commonly used cloth material. 'Church' was replaced by the Tamil word for 'Temple' because most Tamil-speaking Sri Lankans are Hindus. And instead of 'Daisy', 'Jasmine', was selected.

(4) Test of attention for letters:
The English alphabet was replaced with Tamil letters that have a corresponding sound.

(5) Language repetition:
The English version of MoCA has two sentences. The first sentence was translated to retain the same meaning and the same number of words. But the name 'John' was replaced with 'Kannan'. The second sentence was translated to retain the same number of words and also the same meaning without any corrections.

(6) Verbal fluency test:
In the original tool, this test involves naming a maximum number of words beginning with the letter 'F'. The corresponding Tamil 'F' is not used commonly. Therefore, it was replaced with the letter 'P'. The adopted tool and guide were pre tested among ten patents from a medical clinic for chronic diseases at the Teaching Hospital, Jaffna and few corrections were made.

Clinical diagnosis
Older adults attending the Neurology Clinic of Teaching Hospital, Jaffna were subjected to full physical and neurological examination by a neurologist to classify were assessed for test-retest reliability of the MoCA by the same data collector.
We also evaluated interrater reliability by inviting another subgroup of 20 participants (10 with normal cognition and 10 with MCI), who were rated twice by two independent raters with the MoCA-Tamil (Sri Lanka).

Statistical analysis
The Original MoCA tool developers have suggested an additional item be added to persons with 12 years of education or less to minimize errors related to education. Therefore, in this study, an additional item was added to MoCA-Tamil (Sri Lanka) scores for those who had education for 12 years or less (if MoCA-Tamil (Sri Lanka) score < 30). Demographic characteristics across those with normal cognition and MCI were compared using the chi-squared test (for categorical variables) or the student 't' test (for continuous variables). Internal consistency reliability of the MoCA-Tamil (Sri Lanka) was assessed using Cronbach's alpha. Test-retest reliability of the MoCA-Tamil (Sri Lanka) was assessed using intra-class correlation coefficients (ICCs) for baseline and 4 weeks retest scores. ROC curve analysis was performed to determine sensitivity and

Study sample
Study participants were 184 older adults, comprising 85 with "normal" cognition and 99 neurologist-diagnosed MCI. The mean age was 69.7(SD 4.8) years. There was no statistically significant difference in the mean age or sex between normal cognitive and MCI participants but, a significant difference was observed in years of education between the two categories of participants (Table1). Table 2 shows the education-adjusted mean MoCA-Tamil (Sri Lanka) scores of "normal" cognitive and MCI participants. The mean MoCA-Tamil (Sri Lanka) score discriminated the two diagnostic categories of the study participants (p<0.001).

Reliability of MoCA-Tamil (Sri Lanka)
Testretest reliability data were collected from a subsample of 20 participants (Normal cognition and MCI) tested, on average, 28± 1.5 days apart. The mean change in MoCA-Tamil (Sri Lanka) scores from the first to second evaluation was 0.8 ± 1.8 points, and the correlation between the two evaluations was high (correlation coefficient = 0.93, p< 0.001) and suggesting good stability over time.

Internal consistency of MoCA-Tamil (Sri Lanka)
Internal consistency of the scale was assessed using Cronbach's alpha. An alpha value of 0.7-0.9 was considered as evidence to support good internal consistency of the instrument (Streiner, 1993). The internal consistency of the MoCA-Tamil (Sri Lanka) was moderate to high, yielding a Cronbach's alpha of 0.831. This indicated good internal consistency.

Inter-observer reliability
The inter-observer reliability was assessed through the application of the test on the first ten patients in the study by two independent blinded evaluators. A correlation of coefficient and concordance of 0.91 was obtained with a 95% CI of (0.77, 0.99). This correlation and concordance coefficient are considered almost perfect.
According to Table 3. which shows item test statistics, the correlated item-total correlations are basically the correlation between the particular item and a composite score of all the other remaining items. In addition, if the corrected itemtotal correlation is >0.30, it indicates homogeneity between each item and total inventory score. Values <0.30 indicate that a particular item correlates poorly with the overall scale (Abdollahimohammad & Ja'afar, 2014). In this tool, all the items except Naming have higher than expected corrected item-total correlation.
'Cronbach's Alpha, if item removed; is a measure of examining the relationship between the individual item and the total scale. This is the value of Cronbach's alpha for the remaining items if the given item is not included in the scale. So, in this scale, all the subscales' 'Cronbach's Alpha if item removed' are lower than overall scale's Cronbach's alpha (0.831).

Predictive validation
With the use of a cut-off of 26 points (suggested in the literature as the ideal MoCA cut-off score to detect MCI), the MoCA-Tamil (Sri Lanka) detected 90.6% of MCI cases, but specificity was reduced to 44.7% (Table 4) 11 specificity (76.4%). Therefore, 24 points seemed to provide the best balance between sensitivity and specificity (any score of ≤23 was considered to be the abnormal result).

Discussion
The objective of this study was to develop the Tamil (Sri Lanka) version of the MoCA and investigate its reliability and validity as a brief screening tool for MCI among Tamil-speaking Sri Lankan older adults. In Sri Lanka the majority of the population is rapidly ageing. The validation of the MoCA in Tamil (Sri Lanka) will be very useful for the clinicians and especially for the primary care physicians in detecting MCI in order to enhance the provision of appropriate care in time.
The results of this study seem to be in line with previous validation studies using the MoCA. First, the MoCA Tamil (Sri Lanka) mean scores for the diagnostic groups were similar to the ones presented in the original study (Nasreddine et al., 2005 Karunaratne et al., (2011) found that Cronbach's alpha increased when the item naming was removed and they concluded that the contribution of the item 'Naming' to the scale was poor.
Sensitivity and specificity of a tool were determined based on the cutoff point decided with the help of ROC curve. A score which yields the best balance between sensitivity and specificity for the MCI participants was decided as the cutoff score. As described in Table 4 the cutoff score of ≥ 24 discriminate NC from MCI participants with the sensitivity of 84.7% and specificity of 76.4%. This cutoff score provides the positive predictive value (PPV) as 88.9% and negative predictive value (NPV) as 68.4%. When increasing the cut-off value to 26 as recommended by the authors of the original MoCA tool the sensitivity decreased to 68.1% but specificity increased to 97.6%. Because of this reason, it was decided that a score of ≥ 24 was the cut-off value to detect NC from the MCI participants.
The Spanish version of the MoCA validation used scores of ≥23 with the optimal sensitivity (89%) and specificity (79.8%) (Gil et al., 2013). In the Beijing version of the Chinese MoCA validation, the cut-off score for the optimal sensitivity and specificity to detect MCI appeared to be ≥/22 for the MoCA-BJ, at which the sensitivity and specificity were 68.7% and 63.9% respectively (Yu et al., 2012).
Some limitations of this study should be mentioned. This tool cannot be applied to illiterate elders, and therefore they were excluded from the study. Another limitation is the fact that the MCI group was heterogeneous, as different MCI 13 subtypes were included in the sample. In addition, this was not a community study, as the sample was hospital based.

Conclusion
The Validated Tamil (Sri Lanka) MoCA is a reliable and an acceptable tool to assess MCI in the community setting with a cut-off value of ≥ 24. It had 84.7% sensitivity and 76.4% Specificity. The reliability and internal consistency of the tool were higher than the expected level.