Dementia in Melton Mowbray--a validation of earlier findings.

In 1981 a survey of elderly persons aged 75 years and over who belonged to a general practice in Melton Mowbray, Leicestershire found a prevalence of moderate cognitive impairment of 4.7%. The criterion which determined the impairment was a score of 7 or under on the CAPE Information/Orientation (IO) sub-test. The prevalence rate has been considered to be much lower than in some key studies, notably the 13% reported in 1970 from Newcastle upon Tyne. Although rates based on cognitive scales are likely to give different results from those based on diagnostic assessment, the suggestion is that the IO sub-test is an insensitive screening instrument for dementia. Using results on the sensitivity and specificity of the CAPE IO sub-test (cut-point 8/9) to detect moderate or severe dementia as defined by clinical diagnosis using the Cambridge Mental Disorders of the Elderly (CAMDEX) schedule, the adjusted prevalence rates of moderate or severe dementia were found to be 3.4% in 1981 and 5.2% in 1988. Both these figures were lower than the observed rates scoring 8 or under on the IO sub-test, confirming that insensitivity of the IO sub-test was not the reason for the supposed low rate in Melton Mowbray in 1981. As the prevalence of dementia in those aged 75 years and over has been reported by other studies to range from 3% to 24%, it is more likely that high rates are due to screening instruments with low specificity.     

Misclassification of dementia by the mini-mental state examination--are education and social class the only factors?

The 1988 Melton Mowbray Study of the Elderly comprised an initial screen with the Mini-Mental State Examination (MMSE) followed by a detailed clinical assessment using the Cambridge Mental Disorders of the Elderly Examination (CAMDEX) for all those scoring 21 and under on the MMSE, a one in two sample of those scoring 22 or 23 and a one in ten of the remainder. A total of 1579 subjects completed the initial screen with 438 subjects undergoing the CAMDEX assessment. Analysis of those subjects who were found to be free of dementia at the clinical assessment (n = 155) demonstrated that the very elderly, those from the manual social classes and subjects with visual impairments had an increased chance of being misclassified as demented by the MMSE. Low educational level and various measures of physical disability also showed a tendency to result in misclassification as falsely positive by the MMSE when viewed alone but these effects appeared to be due solely to their association with extreme age and/or manual social class.     

The Mini-Mental State Examination: identifying the most efficient variables for detecting cognitive impairment in the elderly.

OBJECTIVES: To study how well the scoring on each item of the MMSE relates to the sum-score when the purpose is to identify persons with cognitive impairment, and to identify an equally effective subset of MMSE items for predicting cognitive impairment. DESIGN: Retrospective survey of MMSE data for 850 elderly. SETTING: A variety of clinical settings. PARTICIPANTS: Mean age 82 years (range 54 to 99), 74% women. The subjects were of three different categories: geriatric in-patients, patients living under supervision, and elderly people living independently at home. RESULTS: Five of the binomial ("State," "Town," "Name a pencil," "Name a watch," "Read and obey") and one of the polychotomous MMSE variables ("Learn three words and repeat immediately") had low sensitivity and gave high percentages of misclassifications versus the sumscore dichotomized at the cut-point 23/24. Univariate logistic regression indicated that the three remaining polychotomous variables ("Spell backwards," "Recall three words," and "Three-stage command") can be scored binomially. Two factors were identified on factor analysis. Logistic regression analysis showed that 12 of the original 20 items predicted the sumscore dichotomized at 23/24 with only 3% misclassifications. Validation against the psychogeriatrician's diagnosis showed that this 12-items MMSE derivative performs as well as the full MMSE. CONCLUSIONS: Six of the 20 MMSE variables perform poorly regarding sensitivity and misclassifications versus the sumscore at cut-point 23/24. Two additional items did not contribute to the prediction of a low/high sumscore. The remaining 12 MMSE items can all be scored binomially and produce a sumscore which is equally as effective as the sumscore of the full MMSE when the purpose is to identify elderly patients with cognitive impairment.     

Effect of education on the mini-mental state examination as a screening test for dementia

We studied whether Mini-Mental State Examination (MMSE) norms for detecting dementia in elderly outpatients vary according to educational attainment. Subjects were 109 elderly outpatients with Alzheimer's dementia and 100 non-demented outpatient controls. Receiver operating characteristics (ROC) of the MMSE were examined among three strata of educational attainment: middle school, high school, and college/graduate school. MMSE ROC curve areas were .95-.96 in the three educational strata. Assuming a dementia prevalence of 10%-30%, the most accurate lower limits of normal for MMSE scores and their attendant sensitivities and specificities were 21 for middle school (.82/.94), 23 for high school (.79/.97), and 24 for college/graduate school (.83/1.00) attainment. These norms accurately classified over 90% of subjects in all three educational strata. We conclude that education-specific norms optimize performance of the MMSE as a screening test for Alzheimer's dementia in elderly outpatients.     

The Montreal Cognitive Assessment, MoCA: a brief screening tool for mild cognitive impairment

OBJECTIVES: To develop a 10-minute cognitive screening tool (Montreal Cognitive Assessment, MoCA) to assist first-line physicians in detection of mild cognitive impairment (MCI), a clinical state that often progresses to dementia. DESIGN: Validation study. SETTING: A community clinic and an academic center. PARTICIPANTS: Ninety-four patients meeting MCI clinical criteria supported by psychometric measures, 93 patients with mild Alzheimer's disease (AD) (Mini-Mental State Examination (MMSE) score > or =17), and 90 healthy elderly controls (NC). MEASUREMENTS: The MoCA and MMSE were administered to all participants, and sensitivity and specificity of both measures were assessed for detection of MCI and mild AD. RESULTS: Using a cutoff score 26, the MMSE had a sensitivity of 18% to detect MCI, whereas the MoCA detected 90% of MCI subjects. In the mild AD group, the MMSE had a sensitivity of 78%, whereas the MoCA detected 100%. Specificity was excellent for both MMSE and MoCA (100% and 87%, respectively). CONCLUSION: MCI as an entity is evolving and somewhat controversial. The MoCA is a brief cognitive screening tool with high sensitivity and specificity for detecting MCI as currently conceptualized in patients performing in the normal range on the MMSE.     

The Human Figure Drawing test as a screen for dementia in the elderly: a community-based study

The Human Figure Drawing (HFD) test is a non-verbal test, mainly based on visuo-spatial and constructional abilities. In screening for dementia, the HFD test can be hypothesised as a good complement to Mini-Mental State Examination (MMSE), which is inherently limited by its verbal nature. In order to test this hypothesis, both MMSE and HFD tests were administered to 461 individuals recruited from a community-based study of the elderly (the Kungsholmen project). According to the Third Revised Diagnostic and Statistical Manual of Mental Disorders, 95 subjects were affected by dementia and 366 were non-demented. We calculated the sensitivity and specificity of MMSE, the HFD test, and the combination of the two. Results showed that MMSE mean scores were significantly reduced between the non-demented group and groups with different severities of dementia. The mean scores of a short version of 29 HFD body details (HFD29) and seven HFD essential body details (HFDess) showed similar, but weaker trends than MMSE. However, the sensitivity increased by 4.2% when HFD29 and HFDess were added to MMSE, compared to the MMSE test alone. This increase partially derived from the portion of questionable and mild demented subjects. Unfortunately, a high drop-out rate was present in the HFD test. We conclude that the use of HFD test has limitations in this well-educated population, due to a high number of refusals and only a small improvement in detecting mild demented cases. The application of this test in lower educated populations requires further investigation.     

Comprehensive geriatric assessment in female elderly patients with Alzheimer disease and other types of dementia

The most visible manifestation of dementia is the progressive inability to activities of daily living (ADL) and to instrumental activities of daily living (IADL). The comprehensive geriatric assessment (CGA) is the validated and recommended instrument to a correct evaluation and decision making in elderly patients. To judge if the decline in cognitive functions is associated with a worsening in functional, emotional and clinical status measured by CGA, we also compared CGA in the same patients stratified for mild, moderate and severe dementia. From September 2004 to November 2005 we studied 47 institutionalized female patients with Alzheimer's disease (AD) and other types of dementia. Mean age was 83.70+/-0.88 years (range 70-101). Their multidimensional evaluation was performed by the CGA. We evaluated geriatric syndromes (AGS, 2004), polypharmacy, frailty, hemoglobin (Hb), serum creatinine (CR) and white blood cells (WBC). We stratified the population in 3 groups for the mini mental state examination (MMSE): severe (MMSE 0-9; 5 patients), moderate (MMSE 10-29; 23 patients) and mild dementia group (MMSE 20-30; 19 patients), and searched for statistical differences in the parameters of CGA. MMSE was significantly related to dependence in ADL (mean=x=1.85), IADL (x=0.57), cumulative illness rating scale-geriatrics (CIRS-G) (x=9.55), geriatric depression scale (GDS) (x=8.71), geriatric syndromes (x=2.49), Hb, CR, WBC and number of drugs (x=6.51, range 2-15) (p=0.001). MMSE low score was also correlated with a worse mini nutritional assessment (MNA) (x=19.5; p=0.003). Frail patients were 61.7%. We found a statistically significant difference in the prevalence of geriatric syndromes between mild vs. moderate dementia group (p=0.02). Mild vs. moderate group, and moderate vs severe group were significantly different concerning Hb levels (p=0.009 and 0.002, respectively). Patients with severe cognitive impairment are more likely to be dependent at ADL and IADL; to present a larger number of comorbidity and geriatric syndromes; to have lower !evels of Hb and higher levels of CR; to be in a worse nutritional status and to take a larger number of drugs. Polypharmacy maybe related to high comorbidity but the risk of irrational drug use should be evaluated. We suggest single testing with CGA as an effective tool providing a comprehensive assessment of elderly, and able to detect unaddressed corrigible problems.     

Instrumental activities of daily living as a screening tool for cognitive impairment and dementia in elderly community dwellers.

OBJECTIVE: To identify which Instrumental Activities of Daily Living (IADL) are related to cognitive impairment, independent of age, sex, and education; to assess the performance of an IADL score using these items in screening for cognitive impairment and dementia in elderly community dwellers. DESIGN: Survey based on the baseline interview of the PAQUID study on functional and cerebral aging. SETTING: Community survey in 37 randomly selected parishes in Gironde, France. SUBJECTS: Random sample of 2,792 community dwellers aged 65 and over (participation rate: 69%). MEASUREMENTS: Two-phase screening: (1) functional assessment, Mini-Mental State Examination (MMSE) and DSM-III criteria for dementia; (2) in DSM-III-positive patients, NINCDS-ADRDA criteria applied by a neurologist. Functional assessment: IADL scale of Lawton and Brody. Criterion standards: cognitive impairment: MMSE score lower than 24; dementia: DSM-III and NINCDS-ADRDA criteria. RESULTS: Four IADL items are correlated with cognitive impairment independent of age, sex, and education: telephone use, use of means of transportation, responsibility for medication intake, and handling finances. A score adding the number of IADL dependencies has a sensitivity of 0.62 and a specificity of 0.80 at the lowest cut-off point (score > 0) for the diagnosis of cognitive impairment. The same score at the same cut-off has a sensitivity of 0.94 and a specificity of 0.71 for the diagnosis of dementia. The prevalence of dementia (2.4%) is reduced by a factor of 12 in subjects independent for the four IADL. CONCLUSION: The four IADL score could be incorporated into the screening procedure for dementia in elderly community dwellers.     

Identification of dementia in epidemiological research: a study on the usefulness of various data sources

BACKGROUND AND AIMS: Prevalence and incidence ratios of dementia in epidemiological studies vary according to the data source used. Medical records, cognitive tests, and registry information are sources frequently used to differentiate dementia from normal aging. The aim of the present study was to compare the identification of dementia from these different sources with that from consensus diagnosis.METHODS: 498 elderly people (age range 70-81 at baseline) enrolled in a Swedish population-based longitudinal twin study (Gender) were evaluated on physical and mental health and interviewed for their socio-demographic background three times during an eight-year period. Reviews of medical records and the Swedish Discharge Registry (DR) were conducted. The 10th percentile was used to differentiate between dementia and non-dementia in all cognitive tests. Scores of 24 or below on the Mini-Mental State Examination (MMSE) (range 1-30) indicated dementia. A consensus conference diagnosed dementia on the basis of total information. The consensus diagnosis was used as the gold standard. RESULTS: MMSE scores (sensitivity 64%, specificity 96%, kappa 0.65) and the review of medical records (sensitivity 57%, specificity 99%, kappa 0.65) were good sources for dementia identification. The precision of medical records increased when recordings of cognitive impairment were included (sensitivity 83%, specificity 98%, kappa 0.84). The discharge registry had low sensitivity (26%) and kappa coefficient (0.31). CONCLUSIONS: The present study shows that both review of medical records and MMSE scores are good although not perfect identifiers of dementia. The discharge registry is an uncertain source of dementia identification.     

Intersecting pentagon copying and clock drawing test in mild and moderate Alzheimer's disease

BackgroundIn Alzheimer's disease (AD) drawing and constructional abilities are impaired and worsen as the disease progresses.PurposeTo examine the feasibility of and develop a method for screening, diagnosis, and staging of dementia that can be quickly administered and interpreted in the clinical setting.MethodsThe study aims to describe a scoring mechanism of the intersecting pentagon copying (IPC) task based on the degree of drawing failure and pitted against the Mini-Mental State Examination (MMSE) and the clock drawing test (CDT), which is probably its most likely competitor for a small measure. This is a prospective cohort study of 91 probable dementia patients of the Alzheimer type referred to the geriatrician over a period of 3 years where the suitability of prescribing acetyl cholinesterase inhibitor is investigated. The patients were categorized as follows: 18 (20%) normal, 31 (34%) mild dementia, and 42 (46%) moderate dementia. The copying of the pentagon was part of the MMSE and these drawings were further scrutinized and a 10-point scoring method developed. Each IPC and CDT was blindly and independently rated by two geriatricians.ResultsThe MMSE and Clinical Dementia Rating were found to have very similar staging results. The IPC had some commonality with these measures for patients defined as normal in that most score 10/10 for the IPC. However, both mild and moderate dementia patients according to other measures have an overlapping range of scores on the IPC scoring method developed. The highest association for the IPC with the CDT was 0.68. IPC had a stronger correlation with the total MMSE than with the two shorter versions.ConclusionThe IPC seems to operate more as a screening tool rather than a dementia staging instrument and assists in identifying normal patients.     

Instruments for screening for depression and dementia in a long-term care facility

The high prevalence of mental disorders such as depression and dementia in institutionalized elderly patients warrants screening for psychiatric diagnosis in patients newly admitted to long-term care facilities. The diagnostic accuracy of the Mini-Mental State Examination (MMSE) and the Geriatric Depression Scale (GDS) was evaluated against a standardized psychiatric interview. The MMSE was found to be 81% sensitive and 83% specific in screening for dementia using a previously established cutpoint of less than 24/30 points. Adjusting MMSE scores for physical disabilities precluding completion of specific tasks on the MMSE did not significantly change the diagnostic accuracy of the test. The GDS was 47% sensitive and 75% specific in screening for depression using the suggested cutpoint of greater than 13/30 points. The MMSE was significantly correlated with functional status (r = 0.48, P = .0001), but not with the scores on the GDS or the clinical diagnosis of depression. The GDS did not correlate with functional status. In summary, the MMSE is a good screening test for dementia in institutionalized elderly, but the GDS is not sensitive for depression in this population.     

Prevalence of dementia in the 'oldest old' of a Dutch community

OBJECTIVE: To estimate the prevalence rate of dementia in subjects 85 years of age and over. DESIGN: A two-phase design with the Mini-Mental State Examination (MMSE) in the screening phase and the Geriatric Mental State Schedule (GMS) in the diagnostic phase. SETTING: Community survey including subjects in residential care. SUBJECTS: All (n = 1,259) inhabitants of Leiden, The Netherlands, aged 85 years and over on December 1, 1986. First phase participation rate was 71% (17% dropout due to death); second phase participation rate was 82%. MAIN OUTCOME MEASURE: DSM-III diagnosis of dementia without further specification of the etiology of the dementia. RESULTS: An overall prevalence rate of 23% (95% C.I.: 19%-26%) was found. This included 12% mild dementia, 7% moderate and 4% severe dementia. The prevalence rate was higher among women (24%) than among men (18%). It increased with age from 19% (95% C.I.: 16%-22%) in the group of 85-89 years to 32% (95% C.I.: 26%-39%) in the group of 90-94 years to 41% (95% C.I.: 25%-58%) in the 95+ group. CONCLUSION: A fifth of the 85+ and a third of the 90+ population suffer from dementia with an indication that half of the 95+ population is affected. With the expected steep rise in the number of the oldest old, dementia will stay a major health problem in the near future.     

Prevalence of Alcohol‐Related Problems in an Elderly Population and Their Association With Cognitive Impairment and Dementia

Background: Studies investigating the association between alcohol use and cognitive disorders in the elderly population have produced divergent results. Moreover, the role of alcohol in cognitive dysfunction is not clear. The aims of this study were to estimate the prevalence of alcohol‐related problems in an elderly population from Brazil and to investigate their association with cognitive and functional impairment (CFI) and dementia. Methods: A community‐based cross‐sectional study was performed. A sample of 1,145 elderly people was examined in 2 phases. Several instruments were utilized in the first phase: the CAGE questionnaire was used to identify potential cases of alcohol‐related problems, and a screening test for dementia was used to estimate CFI. The CAMDEX interview (Cambridge Examination) and DSM‐IV (Diagnostic and Statistical Manual of Mental Disorders, 4th edition) criteria were used for the clinical diagnosis of dementia in the second phase. Results: “Heavy alcohol use” (CAGE ≥ 2) was found in 92 subjects (prevalence: 8.2%). It was associated with gender (males, p < 0.001), low education (only in females, p = 0.002), and low socioeconomic level (p = 0.001, in females; p = 0.002, in males). The Mini Mental State Examination exhibited a nonlinear relationship with alcohol‐related problems in females; “mild–moderate alcohol use” (CAGE < 2) presented the highest score. A significant association between alcohol‐related problems and cognitive dysfunction was found only in females. “Heavy alcohol use” was associated with higher CFI and dementia rates compared to “mild–moderate alcohol use” (p = 0.003 and p < 0.001, respectively). “Mild–moderate alcohol use” had a tendency of association with lower CFI and dementia rates when compared to “no alcohol use” (p = 0.063 and 0.050, respectively). Conclusion: Our findings suggest that alcohol use does not have a linear relationship with cognitive decline.     

The CAMDEX: a standardized instrument for the diagnosis of mental disorder in the elderly: a replication with a US sample

The Cambridge Mental Disorders of the Elderly Examination (CAMDEX) was developed by Roth, et al (1986) to assist in the early diagnosis and measurement of dementia in the elderly. In this study the CAMDEX was administered to a mixed group of independently diagnosed elderly psychiatric patients and control subjects in the United States. The CAMDEX was found to have a high interrater reliability with a mixed group of clinicians of varying backgrounds. The diagnostic scales and the cognitive section of the CAMDEX demonstrated considerable promise in distinguishing between independently diagnosed populations of depressed, demented, and normal subjects. The results suggest comparability between samples of subjects in England and the US, and that the CAMDEX is a promising instrument for use in both research and clinical settings.     

Is Mini‐Mental Score Examination Scoring a New Predictor of Uncontrolled Hypertension?

Essential hypertension is an important risk factor for target organ damage. The brain is among the target organs infrequently visited. The authors evaluated whether an abnormal Mini‐Mental Score Examination (MMSE) score predicts uncontrolled hypertension even if office blood pressure is normal. Seventy‐seven hypertensive patients were included. The cognitive function of each patient was assessed using MMSE and a customized brain magnetic resonance imaging study. Patients were classified into normal cognitive function group and mild, moderate, and severe cognitive impairment groups. A significance level of P=.05 was used. There was a higher percentage of uncontrolled BP in every cognitive impairment class. In patients older than 65 years, MMSE score had a sensitivity and specificity of 94% and 83%, respectively, in the prediction of uncontrolled hypertension. MMSE is a simple test to run in the clinic to predict whether patients have well‐controlled blood pressure.     

Impact of aging on the relationships between impairment of "Orientation" and "Recall" items of MMSE and mild to moderate mood disorders

The association of depression and dementia is far more common than the masking of depression by dementia, i.e., pseudodementia. The impact of aging was investigated on the relationships between mood disorders, evaluated by means of Hamilton Depression Rating Scale (HDRS) and early cognitive impairments, measured by using the Mini Mental State Examination (MMSE) in 100 aged subjects (age range 60-84 years). In our population of mildly to moderately depressed elderly people, the aging was associated with a loss of MMSE item "Orientation" and a loss of MMSE item "Recall"; this could be explained by an association of cognitive impairment and mild to moderate depressive disorders which are worsening with aging.     

Clinical backgrounds and morbidity of cognitive impairment in elderly diabetic patients

Despite numerous reports that have linked diabetes with cognitive impairment (CI), there are few studies that have attempted to clarify the morbidity of CI among elderly diabetic patients. The Mini-Mental State Examination (MMSE) was performed on 240 diabetic patients aged 65 years or older who had no diagnosis of dementia. The MMSE scores were 28-30 (normal range) in 151 patients (63%), 24-27 (suspected CI) in 77 (32%), and ≤ 23 (definite CI) in 12 (5%). Eight of the 12 patients with MMSE scores ≤ 23 underwent further detailed examination: the final diagnosis was Alzheimer's disease (AD) (N = 5), vascular dementia (N = 2), and mixed dementia (N = 1). Among 24 of the 77 patients with MMSE scores of 24-27 who were referred for further detailed examination, the final diagnosis was early AD (N = 5), cerebrovascular disease (CVD) (N = 10), and mild CI (N = 7). Only 2 of the patients were judged as being normal. The percentage of patients with a history of CVD, the rate of diuretic use, and the serum levels of non-high-density lipoprotein cholesterol were higher, and the percentage of patients with a history of habitual alcohol consumption was lower in the low MMSE score group than in the normal MMSE score group. Among elderly diabetic patients aged 65 years or older, 5% had evident CI and 32% had suspected CI. Medical staff involved in the care of diabetic patients should be highly aware of possible CI in this patient population.     

Prevalence rates of dementia in an ageing population: are low rates due to the use of insensitive instruments?

The varying prevalence rates of dementia reported in elderly populations may be partly due to the use of different diagnostic measures. In a recent study in which diagnosis was based on the CAPE, a 12-item questionnaire, the prevalence rate for severe cognitive impairment for the age group 75 years or over was lower than previously reported. In the present study, the performance of the CAPE was examined in an elderly general-practice sample with a higher than usual risk of dementia. The study diagnosis was based on a combination of the diagnosis made by the computer program AGECAT and a clinical diagnosis made by the interviewing psychiatrist. Forty-five per cent of patients with definite or probable dementia, as defined, and 100% of those with possible dementia had scores above the cut-point on the CAPE. The sensitivity of the CAPE was low compared with that of other rating scales. It is concluded that the low reported rate with the CAPE is probably due to only the more severe cases being identified. For comparative purposes it is important to know the level of dementia that the instruments used are detecting.     

Evaluation of a Japanese version of the Mini‐Mental State Examination in elderly persons

Aim: This study aimed to examine the validity and item‐response characteristics of the Mini‐Mental State Examination (MMSE), which is used for assessing cognitive function, in Japanese older adults. Methods: Factor analysis and item response analysis were carried out for MMSE responses (n = 1971) from older adults living in the community (n = 1339) or in a nursing home (n = 632), including Alzheimer‐type dementia (n = 330), vascular dementia (n = 36), frontotemporal dementia (n = 7), mixed Alzheimer‐type and frontotemporal type dementia (n = 27), and age‐related cognitive decline (n = 29). When choosing the cut‐off score of 23 points for the MMSE, sensitivity and specificity for each item were calculated. Results: A three‐factor solution was found to be most appropriate by factor analysis: complex processing, simple processing and working memory. The item characteristics curves showed unidimensionality with high reproducibility. We identified a simplified scale comprising 10 items in all participants: “naming”, “three‐step command”, “registration”, “repeat a sentence”, “write a complete sentence”, “copies drawing of two polygons”, “orientation to place”, “delayed recall”, “orientation to time” and “serial sevens” tasks. Sensitivity and specificity for both “year” task and “day” task were more than 90% (“year”: sensitivity 92.5%, specificity 96.3%; “day”: sensitivity 92.4%, specificity 91.7%). For the Alzheimer‐type dementia patients, the five‐factor solution was suggested by factor analysis and the MMSE also had unidimensionality in terms of level of difficulty. Conclusions: We found that the MMSE had multiple cognitive areas. We showed that the MMSE could be used as an essentially unidimensional measure of cognitive ability and the question about orientation to time might be useful in the simplest assessment to identify cognitive dysfunction. Geriatr Gerontol Int 2012; 12: 310–316.     

The Mini-Cog as a screen for dementia: validation in a population-based sample

OBJECTIVES: To test the Mini-Cog, a brief cognitive screening test, in an epidemiological study of dementia in older Americans. DESIGN: A population-based post hoc examination of the sensitivity and specificity of the Mini-Cog for detecting dementia in an existing data set. SETTING: The Monongahela Valley in Western Pennsylvania. PARTICIPANTS: A random sample of 1,119 older adults enrolled in the Monongahela Valley Independent Elders Survey (MoVIES). MEASUREMENTS: The effectiveness of the Mini-Cog in detecting independently diagnosed dementia was compared with that of the Mini-Mental State Examination (MMSE) and a standardized neuropsychological battery. RESULTS: The Mini-Cog, scored by an algorithm as "possibly impaired" or "probably normal," and the MMSE, at a cutpoint of 25, had similar sensitivity (76% vs 79%) and specificity (89% vs 88%) for dementia, comparable with that achieved using a conventional neuropsychological battery (75% sensitivity, 90% specificity). CONCLUSION: When applied post hoc to an existing population, the Mini-Cog was as effective in detecting dementia as longer screening and assessment instruments. Its brevity is a distinct advantage when the goal is to improve identification of older adults in a population who may be cognitively impaired. Prior evidence of good performance in a multiethnic community-based sample further supports its validity in the ethnolinguistically diverse populations of the United States in which widely used cognitive screens often fail.