Conversion Between the Montreal Cognitive Assessment and the Mini-Mental Status Examination

Jael S. Fasnacht MSc; Alexandra S. Wueest MSc; Manfred Berres PhD; Alessandra E. Thomann PhD; Sabine Krumm PhD; Klemens Gutbrod PhD; Luzius A. Steiner MD, PhD; Nicolai Goettel MD; Andreas U. Monsch PhD

Disclosures

J Am Geriatr Soc. 2023;71(3):869-879.

Abstract and Introduction

Abstract

Background: Early and accurate detection of cognitive changes using simple tools is essential for an appropriate referral to a more detailed neurocognitive assessment and for the implementation of therapeutic strategies. The Mini-Mental Status Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) are two commonly used psychometric tests for cognitive screening. Both tests have different strengths and weaknesses. Preferences regarding test selection may therefore differ among clinicians. The aim of this retrospective observational cohort study was to define corresponding scores for the MMSE and the MoCA.

Methods: We examined the relationship between the cognitive screening tests in 803 German-speaking Memory Clinic outpatients, encompassing a wide range of neurocognitive disorders. We produced a conversion table using the equipercentile equating method with log-linear smoothing. In addition, we conducted a systematic review of existing MMSE-MoCA conversions to create a table allowing for the conversion of MoCA scores into MMSE scores and vice versa using the weighted mean method.

Results: The Memory Clinic sample showed that the prediction of MMSE to MoCA was overall less accurate compared to the conversion from MoCA to MMSE. The 19 studies included after thorough literature search showed that MoCA scores were consistently lower than MMSE scores. Eleven of 19 conversion studies had addressed the conversion of the MoCA to the MMSE, while two studies converted MMSE to MoCA scores. Another six studies applied bi-directional conversions. We provide an easy-to-use table covering the entire range of scores and taking into account all currently existing conversion formulas.

Conclusion: The comprehensive MMSE-MoCA conversion table enables a direct comparison of cognitive test scores at screening examinations and over the course of disease in patients with neurocognitive disorders.

Introduction

The overall prevalence of dementia is increasing with the global aging of populations,^[1] associated with substantial societal, social, and economic challenges. Early identification of cognitive impairment is crucial to allow for early treatment and appropriate advance care planning.^[2] In order to comprehensively identify, describe, and quantify cognitive deficits, extensive neuropsychological diagnostics must take place.^[3] Usually, brief and reliable screening tests are used as an initial step in the process of assessing cognitive impairment.^[4] Most prominent screening tools are the Mini-Mental Status Examination (MMSE)^[5] and the Montreal Cognitive Assessment (MoCA).^[6] These instruments are widely used instruments screening tools, both in everyday clinical practice and in research. They require little training, are easy to administer, and have demonstrated diagnostic utility^[7] to differentiate patients with dementia from individuals with normal cognition.^[8] The MMSE has been criticized for its low sensitivity in patients with mild dementia or mild cognitive impairment (MCI).^[6] Thus, clinicians migrated to prefer the MoCA over the MMSE.^[9] The MoCA, which was developed to identify patients with MCI, is better suited to detect patients in early stages of neurocognitive disorders (NCD).^[10] However, the MoCA might be too difficult for patients in advanced stages of NCD. Scale conversion may facilitate the comparison and synthesis of cognitive data, enhance collaboration between clinicians, and inform clinical and policy decisions in the context of dementia.^[11] There are well-established methods for scale conversions such as equipercentile equating methods. This method was used in most previous studies^[3,12–24] and enables direct and easy comparison of scores.^[25] Some of these publications provided an MMSE-MoCA conversion table.^[12–16,26] However, these studies were generally small sampled, did not appropriately reflect the heterogeneity of patients encountered in daily clinical practice and, therefore, have limited generalizability. Thus, conversions are needed that reflect the relationship between MoCA and MMSE for a broad range of causes of cognitive impairment as (a) patient populations are usually heterogeneous; (b) the cause of cognitive impairment during screening is unclear; and (c) comorbid diseases and conditions are often present.^[17] Moreover, only a few studies considered a bi-directional score equation.^{[17,23,24,27,28]} In most score conversion studies the uni-directional MoCA to MMSE translation was performed,^{[3,9,12–16,19–21,26]} which leads to gaps and overrepresentations in the MMSE score range, making it difficult to unambiguously assign an equivalent MoCA score.^[18] Specifically, it was found that multiple MMSE scores could correspond to one MoCA score at higher levels of cognitive function, while one MMSE score could correspond to multiple MoCA scores at lower levels of cognitive function. For example, in a previous study,^[3] MMSE scores of 1, 3, 6, 8, 10, 12, 15, and 17 were absent from the conversion table. Additionally, more than one MoCA value corresponded to each of the MMSE scores 20, 22, 24, 26, 27, 28, 29, and 30. Thus, these scores were overrepresented. In order to promote the MoCA in clinical practice as a brief cognitive screening test in different domains and to facilitate interpretation of results, several authors recommend translating the full range of MoCA and MMSE scores in the future to make them comparable.^[3,18] Additionally, the majority of previous studies originated from English-speaking samples,^{[9,12–16,19,22,26,27]} while only a few conversion studies were based on German-speaking participants.^[3,16] At present, no study has attempted to compile a comprehensive bi-directional MoCA-MMSE conversion based on all currently available studies. Thus, we aimed to create tables allowing for the conversion of MoCA scores into MMSE scores and vice versa.

1 2 3 4

Next Section

Abstract and Introduction
Methods
Results
Discussion
References
Sidebar

Table 1. Demographic characteristics, clinical test scores, and diagnoses
Group	NF	Mild NCD	Major NCD	Total
n	118	329	356	803
Age in years	63.1 (13.4)	66.6 (13.8)	77.5 (9.8)	71.0 (13.5)
Range	19–88	19–91	19–92	19–92
Education in years	14.4 (3.0)	12.7 (2.9)	11.9 (2.9)	12.6 (3.0)
Range	8–20	7–20	7–20	7–20
Female %	45.8	51.1	57.6	53.2
MMSE score	29.2 (1.0)	27.6 (2.1)	23.9 (3.6)	26.2 (3.5)
Range	26–30	19–30	6–30	6–30
MoCA score	27.0 (2.1)	23.2 (3.8)	17.7 (4.2)	21.3 (5.2)
Range	20–30	12–30	2–30	2–30
Diagnoses %
Alzheimer's disease	-	16.4	77.8	48.3
Vascular disease	-	6.4	0.6	3.4
Frontotemporal lobar degeneration	-	2.4	2.5	2.5
Lewy Body disease	-	0.3	1.4	0.9
Parkinson's disease	-	1.5	0.6	1.0
Traumatic brain injury	-	0.9	0.6	0.7
Brain tumor	-	0.9	0.6	0.7
Substance and/or medication use	-	1.8	1.1	1.5
Epilepsy	-	1.2	0.6	0.9
Multiple sclerosis	-	4.9	2.0	3.4
Depression	-	8.5	0.6	4.4
Multiple etiologies	-	13.1	5.1	8.9
Other	-	15.2	3.1	8.9
Unspecified	-	26.4	3.7	14.6

Note: Demographic data and clinical test scores are presented as mean (SD). Clinical diagnoses are presented as percentages. Years of education was defined as the total number of years in school plus any professional education (not counting years needed to repeat). The maximum education was set at 20 years. In case of multiple specialized educations, only the longest one was counted.
Abbreviations: MMSE, mini mental status examination; MoCA, montreal cognitive assessment; NCD, neurocognitive disorder; NF, normal findings.

Table 2. Conversion table for MoCA and MMSE scores based on equipercentile equating with log-linear smoothing in 329 mild NCD, 356 major NCD, and 118 NF
MoCA score	Equivalent MMSE	95% CI	MMSE score	Equivalent MoCA	95% CI
0	-	-	0	-	-
1	-	-	1	-	-
2	7	[2, 12]	2	-	-
3	9	[3, 15]	3	-	-
4	10	[5, 16]	4	-	-
5	12	[6, 17]	5	-	-
6	13	[8, 18]	6	2	[−1,4]
7	14	[10, 18]	7	2	[−1,5]
8	15	[12, 18]	8	2	[−1,6]
9	16	[14, 18]	9	3	[−1,7]
10	17	[15, 19]	10	4	[0,8]
11	18	[17, 19]	11	5	[1, 9]
12	19	[18, 20]	12	5	[1, 9]
13	20	[19, 21]	13	6	[3, 10]
14	21	[20, 22]	14	7	[4, 10]
15	22	[21, 23]	15	8	[6, 11]
16	23	[22, 23]	16	9	[7, 11]
17	24	[23, 24]	17	10	[8, 12]
18	25	[24, 25]	18	11	[10, 12]
19	25	[25, 26]	19	12	[11, 13]
20	26	[26]	20	13	[12, 14]
21	27	[26, 27]	21	14	[13, 15]
22	27	[27, 28]	22	15	[14, 16]
23	28	[28]	23	16	[15, 17]
24	28	[28, 29]	24	17	[17, 18]
25	29	[29]	25	19	[18, 19]
26	29	[29]	26	20	[19, 21]
27	30	[29, 30]	27	21	[21, 22]
28	30	[30]	28	23	[23, 24]
29	30	[30]	29	25	[25, 26]
30	30	[30]	30	28	[28, 29]

Note: MoCA was adjusted for the years of education (i.e., +1 point when years of education was ≤12 years).
Abbreviations: CI, confidence interval; MMSE, mini-mental status examination; MoCA, montreal cognitive assessment; NCD, neurocognitive disorder; −, values were not reported.

Table 3. Comprehensive conversion table for each possible MoCA and MMSE scores
Raw MoCA score	Equivalent MMSE score (N = 9425)		Raw MMSE score	Equivalent MoCA score (N = 4262)
Raw MoCA score	Weighted mean score	Range	Raw MMSE score	Weighted mean score	Range
0	5	0–15	0	0	0–1
1	7	2–15	1	0	0–1
2	9	2–16	2	0	0–1
3	10	5–16	3	0	0–1
4	11	6–17	4	0	0–1
5	12	8–17	5	0	0–2
6	13	10–18	6	0	0–3
7	14	11–19	7	1	0–4
8	15	12–19	8	1	0–4
9	16	14–20	9	2	0–5
10	17	15–20	10	3	0–5
11	18	16–21	11	4	0–6
12	19	17–21	12	4	0–7
13	20	18–22	13	5	0–8
14	20	19–22	14	6	0–8
15	21	20–23	15	7	0–9
16	22	21–23	16	8	2–10
17	23	22–24	17	9	4–11
18	24	22–25	18	10	6–12
19	25	23–26	19	11	8–13
20	25	24–26	20	12	10–14
21	26	25–27	21	13	12–17
22	27	26–28	22	14	13–18
23	27	26–29	23	16	15–18
24	28	27–30	24	17	16–19
25	28	28–29	25	19	18–20
26	29	28–30	26	20	20–21
27	29	29–30	27	22	21–23
28	29	29–30	28	23	22–25
29	30	30–30	29	26	23–27
30	30	30–30	30	28	24–29

Abbreviations: MMSE, mini mental status examination; MoCA, montreal cognitive assessment.

Authors and Disclosures

Jael S. Fasnacht MSc¹, Alexandra S. Wueest MSc^1,2, Manfred Berres PhD³, Alessandra E. Thomann PhD^1,2, Sabine Krumm PhD^1,4, Klemens Gutbrod PhD⁵, Luzius A. Steiner MD, PhD^2,6, Nicolai Goettel MD^6,7 and Andreas U. Monsch PhD^1,4,8

¹From the Memory Clinic, University Department of Geriatric Medicine FELIX PLATTER, Basel, Switzerland
²Department of Anesthesiology, Intermediate Care, Prehospital Emergency Medicine and Pain Therapy, University Hospital Basel, Basel, Switzerland
³Department of Mathematics and Technology, University of Applied Sciences Koblenz, Germany
⁴Faculty of Medicine, University of Basel, Basel, Switzerland
⁵Neurozentrum Bern and Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
⁶Department of Clinical Research, University of Basel, Basel, Switzerland
⁷Department of Anesthesiology, University of Florida College of Medicine, Gainesville, Florida, USA
⁸Faculty of Psychology, University of Basel, Basel, Switzerland

Correspondence
Alexandra S. Wueest, From the Memory Clinic, University Department of Geriatric Medicine FELIX PLATTER, Basel, Switzerland. Email: alexandra.wueest@felixplatter.ch

Jael S. Fasnacht and Alexandra S. Wueest contributed equally to this study.

Author Contributions
Jael S. Fasnacht: conception design; acquisition of data; analysis and interpretation of data; drafting the article; revising the article critically for important intellectual content; final approval. Alexandra S. Wueest: acquisition of data; analysis and interpretation of data; drafting the article; revising the article critically for important intellectual content; final approval. Manfred Berres: interpretation of data; statistical analysis; revising the article critically for important intellectual content; final approval. Sabine Krumm: analysis and interpretation of data; revising the article critically for important intellectual content; final approval. Alessandra E. Thomann, Klemens Gutbrod, Luzius A. Steiner, and Nicolai Goettel: revising the article critically for important intellectual content; final approval. Andreas U. Monsch: conception design; revising the article critically for important intellectual content; final approval.

Conflict of Interest
Alessandra E. Thomann is a full-time employee and shareholder of F. Hoffmann-La Roche Ltd., her contribution to the submitted publication is related to work done at a previous employment. Nicolai Goettel has received consultancy fees from PIPRA AG, Zurich, outside the submitted work. The other remaining authors have no conflicts of interest to report.