ORIGINAL ARTICLE Year : 2022  |  Volume : 27  |  Issue : 6  |  Page : 531-537

The correlation and agreement of montreal cognitive assessment, mini-mental state examination and abbreviated mental test in assessing the cognitive status of elderly people undergoing hemodialysis

Maryam Rahmani1, Azar Darvishpour2, Parand Pourghane1
1 Department of Nursing, Zeynab (P.B.U.H) School of Nursing and Midwifery, Guilan University of Medical Sciences, Rasht, Iran
2 Department of Nursing, Zeynab (P.B.U.H) School of Nursing and Midwifery, Guilan University of Medical Sciences; Social Determinants of Health Research Center, Guilan University of Medical Sciences, Rasht, Iran

Date of Submission31-Mar-2021Date of Decision13-Jun-2021Date of Acceptance23-May-2022Date of Web Publication18-Nov-2022

Correspondence Address:
Azar Darvishpour
Zeynab (P.B.U.H) School of Nursing and Midwifery, Martyr Yaghoub Sheikhi St. Leyla Kooh, Langeroud, Guilan
Iran

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/ijnmr.ijnmr_56_21

Background: Cognitive disorders are one of the most common disorders in elderly people with chronic renal failure. This study aimed to investigate the correlation and agreement of Montreal Cognitive Assessment (MoCA), Abbreviated Mental Test Score (AMTS), and Mini-Mental State Examination (MMSE) tests in assessing the cognitive status of elderly patients undergoing hemodialysis at Guilan University of Medical Sciences in north of Iran. Materials and Methods: This cross-sectional study was conducted on 84 elderly people undergoing hemodialysis. Inclusion criteria was having an age of 60 years old and older, hemodialysis treatment for at least 6 months, and having reading and writing skills. The Pearson correlation test, Intraclass Correlation Coefficient (ICC) test, and Bland–Altman plot were used for data analysis. Results: The majority of samples were in the age group of 60–65 years (28.57%) and the majority of them were male (66.66%). The results showed a significant positive correlation between MoCA and MMSE (r = 0.69, p = 0.001), between MMSE and AMTS (r = 0.64, p = 0.001), and between MoCA and AMTS tests (r = 0.62, p = 0.001). The results also showed a weak agreement between MoCA and MMSE tests (ICC = −0.11, p = 0.633), between MMSE and AMTS tests (ICC = −0.007, p = 0.369), and between MoCA and AMTS tests (ICC = −0.001, p = 0.780). Conclusions: Based on the results, these tools seem to complement each other. The inconsistency between cognitive tests indicates a serious need to develop appropriate instruments for detecting cognitive disorders in elderly.

Keywords: Aged, kidney failure, Mental Status and Dementia Tests, cognitive dysfunction, hemodialysis

How to cite this article:
Rahmani M, Darvishpour A, Pourghane P. The correlation and agreement of montreal cognitive assessment, mini-mental state examination and abbreviated mental test in assessing the cognitive status of elderly people undergoing hemodialysis. Iranian J Nursing Midwifery Res 2022;27:531-7
How to cite this URL:
Rahmani M, Darvishpour A, Pourghane P. The correlation and agreement of montreal cognitive assessment, mini-mental state examination and abbreviated mental test in assessing the cognitive status of elderly people undergoing hemodialysis. Iranian J Nursing Midwifery Res [serial online] 2022 [cited 2022 Nov 23];27:531-7. Available from: https://www.ijnmrjournal.net/text.asp?2022/27/6/531/361483   Introduction 

Ageing is a natural process. In the broader sense, ageing reflects all the changes taking place over the course of life.[1] Aging is a progressive functional decline characterized by a gradual deterioration in physiological function and behavior.[2] As the population ages, the risk of chronic diseases increases and the need for more care increases.[3],[4] The prevalence of Chronic Kidney Disease (CKD) as a serious public health problem is growing in the elderly.[5] Over the past two centuries, the number of elderly patients with chronic renal failure has increased in most countries.[6] This trend poses an increasing burden on dialysis centers.[7] On the other hand, the relationship between cognitive impairment and chronic renal failure has been reported in various studies.[8],[9],[10],[11] Based on the evidence, with age, predictable and reproducible changes in natural cognition occur.[12] Contributing to the high cost of CKD is the remarkably high prevalence of cognitive impairment or overt dementia that ranges from 20% to 50% in older patients with moderate CKD and may reach as high as 70% in severe CKD/dialysis.[13]

Patients with CKD are at increased risk for cognitive decline.[14] Cognitive decline is one of the behavioral manifestations of brain damage in CKD.[15] Cognitive impairment in patients with chronic renal failure shows increasing prevalence,[16] so that the prevalence of moderate to severe cognitive impairment among hemodialysis or peritoneal dialysis patients was >2.5 times higher than that found in healthy controls.[17] In evaluating the relationship between chronic renal disease and cognitive impairments, researchers have shown that renal functioning decline is associated with a decline in cognitive functioning, especially in the areas of general cognitive ability, abstract reasoning, and verbal memory.[7] Cognitive impairment impacts patients negatively by contributing to functional dependence and behavioral symptoms that result in poor outcomes and decreased medication and medical care compliance.[13] Cognitive changes affect patients' quality of life[12] and may even interfere with their social and work performance.[18] Additionally, it more than doubles mortality risk and increases days spent in the hospital, contributing to the tremendous individual, societal, and economical burden of CKD.[13] Thus, the diagnosis of cognitive impairments associated with chronic renal disease is crucial for both the patients and their families, and cognitive status screening can help identify at-risk patients, and awareness of the predictability of cognitive impairment in functional disability can improve the level of care for the elderly.[19] Also, when it is possible to prevent or delay the complications of an underlying disease by therapeutic interventions, screening for the disease in the early stages of the disease seems to be reasonable.[20] Cognitive status screening by health staff and physicians can help identify at-risk elderly people and to develop and implement programs to delay the onset or progression of cognitive impairment in this group.[19] As well, the diagnosis of Mild Cognitive Impairment (MCI) in elderly people can prevent dementia.[21] In this regard, having a confirmatory instrument to ensure the diagnosis of MCI can be helpful for clinical professionals. One of the instruments that has always been used by professionals and researchers is the Mini-Mental State Exam (MMSE), which was first developed by Folstein et al., in 1975.[22] However, to complete the various aspects of MCI diagnosis, newer instruments in this field are needed. Hence, another instrument, called the Montreal Cognitive Assessment (MoCA) test was introduced in this area. Nasreddine et al. (2004)[23] designed this instrument. This test assesses a wider range of cognitive domains compared to the MMSE.

The abbreviated cognitive test (i.e., abbreviated mental test score, AMTS) is also an instrument used to assess cognitive status. It is less dependent on the subject's education compared to similar questionnaires, such as MMSE.[24] This instrument was first developed by Hodkinson in 1972.[25] Then Qureshi and Hodkinson, during a study in 1974, determined its sensitivity and specificity.[26] Diagnosis of cognitive impairments (including MCI and dementia) is difficult for clinical professionals.[27] International guidelines recommend that older people should be assessed in terms of cognitive impairment. The use of cognitive screening instruments is still controversial. There is not an agreement on the best method of its assessment and various screening strategies, including the use of one test, two tests, or a combination of tests that have been reported.[28] Therefore, there is a great need to identify instruments that can easily diagnose suspected disorders.[29] In this regard, various studies have investigated the consistency of cognitive status assessment instruments. In the study of Emery et al. (2020),[30] the AMTS was identified as highly specific for cognitive impairment but relatively insensitive and a quarter of those with normal AMTS had moderate/severe impairment on the MoCA test. The results of the study conducted by Chehrehnegar et al. (2011)[29] showed inconsistency between the results of MoCA and MMSE tests. The results of the study conducted by Lazo-Porras et al. (2016)[28] to evaluate the association among MoCA, MMSE, and LCT (Leganes cognitive test) tests, showed that there were significant differences among three common screening tests in terms of assessing cognitive impairments. Despite recent studies conducted on cognitive functioning assessment tests, no study has yet been conducted to examine the correlation among common cognitive instruments (MoCA, MMSE, and AMT). Therefore, given the diversity of cognitive status assessment instruments and because screening and early identification of at-risk elderly people can be a major step in preventing cognitive impairments and disabilities in this high-risk group, this study aimed to investigate the correlation and agreement of MoCA, AMTS, and MMSE tests in assessing the cognitive status of elderly patients undergoing hemodialysis.

  Materials and Methods 

The present study was a cross-sectional study. The sample included 84 elderly patients undergoing hemodialysis at Guilan University of Medical Sciences in the north of Iran in 2019. Sample size based on the study by Olson et al. (2008)[31] with p1 = 0.30 (prevalence of cognitive impairment with MMSE tool) and p2 = 0.80 (prevalence of cognitive impairment with MoCA instrument), and a significance level of 0.05, 50 sample were calculated and in order to increase the accuracy and calculation of sample attrition, 84 people were finally determined. Inclusion criteria was having an age of 60 years old and older, hemodialysis treatment (at least 6 months), and having reading and writing skills in Persian. Noninclusion criteria included severe visual, hearing, and speech impairments, inability to communicate, having muscular weakness in the dominant hand (to draw and write questionnaires), mental retardation, use of psychotropic drugs in the last year, and a history of drug addiction. Multistage cluster sampling was used in this study. Accordingly, 13 public health centers of Guilan in the north of Iran with the hemodialysis department were divided into three clusters of center, west, and east of Guilan province. Then, two centers were selected from west and east clusters. In the center cluster, only one hospital (Razi Hospital) was equipped with dialysis and that center was selected. Afterward, according to the share of each treatment center in the required sample size, the samples were randomly selected based on the list of patients undergoing dialysis.

For sampling, the researcher, after obtaining permission from the ethics committee of the university's vice chancellor and also the dean of the faculty of Nursing and Midwifery, referred to the selected medical centers to conduct research. After selecting the subjects and introducing herself to them and providing sufficient explanations about the purpose of the research and obtaining their written consent, the researcher completed the questionnaires during the interview with them. Research instruments included demographic characteristics and MoCA, MMSE, and AMT questionnaires, which are described below.

MMSE is a 30-question screening test that quantitatively examines the severity of cognitive impairments and cognitive changes over time in six domains, including time and space orientation, three-word recording, attention and calculation, three-word recall, language and its skills, and visual structure skills.[32] This test is a short mini-test that can be performed in 10 min or less.[33] The MMSE is a paper-based test with a maximum score of 30. The lower scores indicate more severe cognitive problems. The scoring in this test is done in this way: 0–10 (severe cognitive impairment), 11–20 (moderate cognitive impairment), 21–26 (MCI), and 27–30 (normal cognition).[34] Various studies have been conducted to investigate the psychometric properties of the MMSE. For example, Folstein et al.,[22] in 1975, calculated its reliability at 0.88. In the study of Khodamoradi et al. (2020),[35] the total Cronbach's alpha value for all domains of MMSE was >0.7. The reliability of this tool in the present study based on Cronbach's alpha coefficient was 0.80.

MoCA questionnaire is a cognitive screening questionnaire designed by Nasreddine et al., in 2005.[23] This one-page test has a maximum score of 30 and lasts <15 min.[36] The questionnaire assesses more cognitive domains and comprises more complex skills than MMSE, making it more sensitive to MCI diagnosis. The test assesses eight cognitive domains through various skills, including short-term memory (delayed recall), visual-spatial skills (drawing cube and clock), executive functions (following numbers and letters, speech and abstraction), attention, concentration, working memory (deletion, subtraction, counting capacity), language (naming, repetition of sentence), and awareness of time and place.[37] The scoring on this test is as followed: ≥26 (natural status) and <26 (MCI).[29] The results of a study conducted by Nasreddine et al.,[23] in 2005, showed that the reliability of the test using Cronbach's alpha coefficient was 0.92. Also, the reliability of this test in a study conducted by Duro et al.[32] in 2010 was reported at 0.90 using Cronbach's alpha. In the study by Rashedi et al. (2021),[38] the Cronbach α of the MoCA was 0.86. The reliability of this scale in the present study based on Cronbach's alpha coefficient was 0.87.

The AMT is a 10-item instrument designed by Hodgkinson in 1972 to assess the cognitive status.[25] It is one of the most widely used cognitive status screening methods in the world.[39] The implementation of AMT takes only 3 min. The test assesses orientation, concentration/attention, short-term and long-term memory, and is used to screen cognitive impairments in the elderly. In this questionnaire, a score of 10 is given for each correct answer. The lower the total score, the more severe the cognitive impairment.[36] A score of 0–3 indicates severe cognitive impairment, a score of 4–6 indicates moderate cognitive impairment and a score of 7–10 indicates normal cognitive status.[26] The reliability and validity of this test have been evaluated in different countries. For example, the Spanish version of the AMT was tested in the Spanish rural community and its sensitivity was reported at 100% and its specificity was reported at 53% with a cut-off point of 7–8.[40] In Iran, the validity and reliability of AMT in a group of Iranian elderly people living in a nursing home were also assessed in a study conducted by Foroughan et al in 2017. The internal consistency of AMT was also estimated at 0.90 using Cronbach's alpha method.[39] The reliability of this tool in the present study based on Cronbach's alpha coefficient was 0.78.

The Pearson correlation test was used to evaluate the correlation of the questionnaires presented in this study. Intraclass Correlation Coefficient (ICC) and the Bland–Altman plot were used to examine the consistency between the instruments. The obtained data were analyzed by the Statistical Package for the Social Sciences (SPSS) version 20 software (IBM Corp. Armonk, New York).

Ethical considerations

Ethical considerations of the research included approval of the research plan, obtaining the permission from the Ethics Committee of Guilan University of Medical Sciences (Ethics code No: IR.GUMS.REC.1397.266), obtaining patients' consent and cooperation, assuring confidentiality, and allowing the subjects to withdraw from the study.

  Results 

The results of the present study showed that the majority of subjects were in the age group of 60–65 years (28.57%) and the majority of them were male (66.66%). The results of the demographic characteristics of elderly people undergoing hemodialysis at Guilan University of Medical Sciences are presented in [Table 1].

Table 1: Demographic characteristics of the elderly people undergoing hemodialysis at Guilan University of Medical Sciences (n=84)

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The results of the correlation between the Montreal Cognitive Test (MoCA) and the Mini-Mental State Examination (MMSE) in assessing the cognitive status of elderly people undergoing hemodialysis indicated a positive and significant relationship between the two tests (p = 0.001, r = 0.69). Intraclass correlation results showed weak agreement between the two tests (p = 0.633, ICC = −0.11) to determine the correlation between the MoCA and MMSE tests [Table 2]. The Bland–Altman plot in [Figure 1] indicates this issue.

Table 2: Correlation and agreement between MoCA* and MMSE** tests (n=84)

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The results of the correlation between the MoCA and the AMTS tests also showed a positive and significant relationship between the two tests (r = 0.64, p = 0.001). Intraclass correlation results also showed disagreement or partial agreement between the two tests of MoCA and AMTS (p = 0.36, ICC = −0.007) [Table 3]. The Bland–Altman plot in [Figure 2] also illustrates this issue.

Table 3: Correlation and agreement between the MoCA* and AMTS** tests (n=84)

Click here to view

The results of the correlation between MMSE and AMTS tests also showed a significant positive relationship between these two tests (r = 0.62, P = 0.001). Intraclass correlation results also showed disagreement or partial agreement between MMSE and AMTS tests (p = 0.780, ICC = −0.001) [Table 4]. The Bland–Altman plot in [Figure 3] also illustrates this issue.

Table 4: Correlation and agreement between MMSE* and AMTS** tests (n=84)

Click here to view

  Discussion 

The present study aimed to investigate the correlation and agreement of common cognitive tests (MoCA, MMSE, and AMT) in elderly patients undergoing hemodialysis at Guilan University of Medical Sciences. The results of the correlation between MoCA and MMSE tests in assessing cognitive status of elderly people undergoing hemodialysis showed that there was a positive and significant correlation between these tests. This indicates that both tests are valid for assessing the cognitive status. Consistent with the present study, the results of the study conducted by Tiffin-Richards et al. (2014)[41] showed a positive and moderate correlation between total MoCA and MMSE scores. In line with the results of the present study, the results of the study conducted by Trzepacz et al.[42] also showed that there was a significant correlation between the scores of these two tests. Also, the results of the present study are consistent with those of the studies conducted by Rambe et al. (2017) and[43] Roalf et al. (2017).[44] However, the results of the study conducted by Rademeyer et al.[45] showed that there was a significant difference between the mean scores of these two tests in assessing patients' cognitive functioning, which indicates that the findings of the present study are not consistent with it. The reason for this difference may also be due to the difference of the study population in the two studies. Because the above study was conducted on schizophrenia patients, and the present study was conducted on elderly patients undergoing hemodialysis.

The results of the agreement of the MoCA and MMSE tests in assessing the cognitive status of elderly people undergoing hemodialysis showed that these tests were not consistent in agreement with each other. The results of the study conducted by Chehrehnegar et al.[29] also showed that there was no agreement between these two tests, which is consistent with the results of the present study. In the study conducted by Lazo-Porras et al. (2016),[28] the agreement between MoCA and MMSE tests was obtained at 63.3%. In the study conducted by Olson et al. (2008),[31] MoCA and MMSE tests did not have an agreement in assessing cognitive status in 50% of patients. Luis et al. (2009)[46] reported that MoCA is more sensitive than MMSE. In the study conducted by Lee et al. (2018),[47] MoCA was reported as a more sensitive instrument than MMSE in the diagnosis of cognitive impairment in patients undergoing hemodialysis. The results of the study conducted by Tiffin-Richards et al.[41] (2014) showed that although MMSE can detect cognitive impairment in patients undergoing hemodialysis, it is less suitable for early detection of MCI. Finally, in their study, the researchers reported that MoCA was an appropriate cognitive screening instrument for hemodialysis patients.

The results of the present study on the correlation between the MoCA and AMTS tests in assessing the cognitive status of elderly people undergoing hemodialysis showed that there was a positive and significant correlation between these tests. This indicates that both tests are valid for assessing cognitive status. The results of the study carried out by Chehrehnegar et al.[29] are also in line with the results of the present study. In the study conducted by Pendlebury et al.,[48] the correlation between the AMTS and MoCA tests was also reported at a high level, which is in line with the results of the present study.

The results of this study conducted to examine the agreement of the MoCA test with the AMTS test in assessing the cognitive status of elderly people undergoing hemodialysis showed that these tests were not in agreement. There was no similar study to discuss and interpret the results in this case. Considering the inconsistency of the two instruments, despite correlating with each other, it should be noted that the correlation does not show agreement, and only the alignment can be deduced from it. In other words, there may be a strong correlation between the two measurements, but the two measurements do not agree.[49]

The results of this study on the correlation between MMSE and AMTS tests in assessing the cognitive status of elderly people undergoing hemodialysis showed that there was a positive and significant correlation between these tests. This result is in line with the result of the study conducted by Foroughan et al.[39] on the presence of correlation between these two instruments. The results of the study conducted by Pendlebury et al.[48] are also in line with the results of the present study.

The results of this study on the agreement of the MMSE and AMTS tests in assessing the cognitive state of elderly people undergoing hemodialysis showed that these tests were not in agreement. Concerning the discussion and interpretation of the results, in this case, no similar study was found in the review of the existing studies. Although it makes it difficult to compare this study with other studies to strengthen, and it is considered as a limitation of the study, it can also be considered as strength of this study as it provides new information in this regard.

However, cognitive impairment influences quality of life, employment rates, treatment adherence, hospital admissions, health care costs, morbidity, and mortality.[10] The association of the elderly with this disease increases its negative effects. While the MMSE has a long history of use in clinical and research settings for the assessment and monitoring of acute neurocognitive impairments, it has limited utility in detecting subtle changes in cognition that may signal pending impairment in at-risk individuals and has a relatively poor accuracy in identifying patients with MCI.[44] MoCA is a simple screening tool that is valid for a patient's initial study and clinical practice in outpatient clinics, although it may have a lack in the specificity that can be assessed the patient's cognitive status by more accurate neurophysiological tests.[10] Comparisons of these two measures find that the MoCA has better sensitivity and specificity in MCI. Thus, the MoCA may be most informative when attempting to differentiate mild forms of dementia from typical age-related decline. However, one of the most significant limitations of the MoCA is the 10–15 min administration time.[44] Abbreviated cognitive test (AMTS) is one of the most widely used methods of screening the cognitive status of the elderly in the world, due to its shortness, speed of execution, need for brief training, simplicity, reproducibility, and possibility to follow the elderly in different periods of health before the onset of dementia, no dependence on literacy and also, low communication in language and culture, method sounds plausible.[30]

Early and accurate detection of cognitive impairment in older adults that indicate transition to dementia can enhance clinical management as well as lead to better understanding of individual differences in disease progression.[44] However, the appropriate tools for screening cognitive status in primary care, in addition to being concise and taking little time to complete, should be reliable and easy to use, and these should be considered in addition to saving time. Accordingly, the AMTS test seems to be a more appropriate tool in terms of saving time in clinics and emergency centers, but in hospitals and nursing homes where there is more opportunity to assess the cognitive status of the elderly, the use of MOCA and MMSE tools is recommended. One of the limitations of this study is that this study was performed on the elderly undergoing hemodialysis in Guilan province and, therefore, cannot be generalized to the elderly with other diseases. The multiplicity of questionnaires is another limitation of this research which was out of the researcher's control due to the main purpose of the research. However, in order to prevent the clients' fatigue, an attempt was made to complete the questionnaires during dialysis and at intervals.

  Conclusion 

The results of correlation and agreement of the MoCA, MMSE, and AMTS tests showed that despite the positive and significant correlation, these tests were not in agreement. These instruments seem to complement each other and should be used together for proper screening. However, given the importance of the subject, studies on other demographic groups seem to be necessary. Due to the importance of screening the cognitive status of the elderly undergoing hemodialysis to prevent the progression of mild cognitive disorders to severe cognitive disorders, dementia, and Alzheimer's and the lack of studies to support the findings in the present study, further studies are suggested.

Acknowledgements

The authors would like to thank ethics Committee of Guilan University of Medical Sciences in Rasht, Iran for approving the project. Hereby, we would like to thank the chief and the personnel of hemodialysis wards at Guilan University of Medical Sciences' hospitals who helped us through the research process and the patients who participated in our study.

Financial support and sponsorship

Guilan University of Medical Sciences, Rasht, Iran

Conflicts of interest

Nothing to declare.

 

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