Screening for Alzheimer's disease among illiterate elderly: accuracy analysis for multiple instruments

One of the challenges in screening for dementia in developing countries is related to performance differences due to educational and cultural factors. This study evaluated the accuracy of single screening tests as well as combined protocols including the Mini-Mental State Examination (MMSE), Verbal Fluency animal category (VF), Clock Drawing test (CDT), and Pfeffer Functional Activities Questionnaire (PFAQ) to discriminate illiterate elderly with and without Alzheimer's disease (AD) in a clinical sample. Cross-sectional study with 66 illiterate outpatients diagnosed with mild and moderate AD and 40 illiterate normal controls. Diagnosis of AD was based on NINCDS-ADRDA. All patients were submitted to a diagnostic protocol including a clinical interview based on the CAMDEX sections. ROC curves area analyses were carried out to compare sensitivity and specificity for the cognitive tests to differentiate the two groups (each test separately and in two by two combinations). Scores for all cognitive (MMSE, CDT, VF) and functional assessments (PFAQ) were significantly different between the two groups (p < 0.001). The best screening instruments for this sample of illiterate elderly were the MMSE and the PFAQ. The cut-off scores for the MMSE, VF, CDT, and PFAQ were 17.5, 7.5, 2.5, and 11.5, respectively. The most sensitive combination came from the MMSE and PFAQ (94.1%), and the best specificity was observed with the combination of the MMSE and CDT (89%). Illiterate patients can be successfully screened for AD using well-known screening instruments, especially in combined protocols.     

Improvement of Screening Accuracy of Mini-Mental State Examination for Mild Cognitive Impairment and Non-Alzheimer's Disease Dementia by Supplementation of Verbal Fluency Performance

Objective

This study aimed to investigate whether the supplementation of Verbal Fluency: Animal category test (VF) performance can improve the screening ability of Mini-Mental State Examination (MMSE) for mild cognitive impairment (MCI), dementia and their major subtypes.

Methods

Six hundred fifty-five cognitively normal (CN), 366 MCI [282 amnestic MCI (aMCI); 84 non-amnestic MCI (naMCI)] and 494 dementia [346 Alzheimer''s disease (AD); and 148 non-Alzheimer''s disease dementia (NAD)] individuals living in the community were included (all aged 50 years and older) in the study.

Results

The VF-supplemented MMSE (MMSE+VF) score had a significantly better screening ability for MCI, dementia and overall cognitive impairment (MCI plus dementia) than the MMSE raw score alone. MMSE+VF showed a significantly better ability than MMSE for both MCI subtypes, i.e., aMCI and naMCI. In the case of dementia subtypes, MMSE+VF was better than the MMSE alone for NAD screening, but not for AD screening.

Conclusion

The results support the usefulness of VF-supplementation to improve the screening performance of MMSE for MCI and NAD.     

认知功能筛查量表在MCI和轻度AD患者中的应用

目的:探讨认知功能筛查量表在轻度认知功能损害(Mild Cognitive Impairment,MCI)和轻度阿尔茨海默病(Alzhei mer disease,AD)患者中的应用。方法:对61例MCI患者和47例轻度AD患者进行系列神经心理学测验,同时选择41例正常老年人做对照。结果:MCI组和正常老年人比较,MGR、MMSE的短时记忆亚项、FOM、LM、DR、CDT均有统计学差异。轻度AD组和MCI组比较,MMSE的即刻记忆亚项、RVR、DS、ADL、IADL、POD均有统计学差异。CES-D在三组间无统计学差异。结论:MGR量表可用来鉴别正常人和认知功能损害人群,但不宜用来鉴别MCI和轻度AD患者。RVR和DS量表可以用于鉴别MCI和轻度AD患者。ADL量表在轻度AD患者显示损害,提示AD患者存在日常生活行为能力的损害。     

Detecting cognitive impairment in primary care: performance assessment of three screening instruments

Early detection of Alzheimer's disease and related disorders (ADRD) is important, especially in primary care settings. We compared performances of two common screening tests, the Mini-Mental State Exam (MMSE) and Clock Drawing Test (CDT), with that of the MCI Screen ({MCIS}) in 254 patients over 65. None had previous diagnosis of ADRD, and 81% were asymptomatic by Functional Assessment Staging Test ({FAST}) (FAST=1). 215 patients completed all screening tests - 141 had >or= 1 abnormal result, 121/141 completed standardized diagnostic assessment, and the remaining 74/215 (34%) screened entirely normally and weren't further evaluated. Potential bias due to unevaluated cases was statistically adjusted. Among diagnosed cases: AD=43%, cerebrovascular disease=36%, other causes=21%. Bias-adjusted MCI prevalence for FAST stages 1 and 1-3 were 13.9-20.3% and 23.0-28.3%. Bias-adjusted results for the CDT, MMSE and MCIS were: clinical diagnosis validity (kappa statistic)={-0.02 (p=0.61), 0.06 (p=0.23), 0.92 (p< 0.0001)}; sensitivity={59%, 71%, 94%}; specificity={39%, 36%, 97%}; overall accuracy={54%, 62%, 96%}; positive predictive value={16%, 17%, 86%}; and negative predictive value={83%, 87%, 96%}. The MMSE and CDT were not valid for early detection, while the MCIS had high validity and accuracy in the primary care cohort.     

Japanese version of the Test Your Memory as a screening test in a Japanese memory clinic

A self-administered cognitive test (Test Your Memory, TYM) is designed as a screening test for the detection of Alzheimer disease (AD). We compared the diagnostic utility of the Japanese version of the TYM (TYM-J) in AD and mild cognitive impairment (MCI) with that of the Mini-Mental State Examination (MMSE) and Alzheimer's Disease Assessment Scale—Cognitive Subscale Japanese version (ADAS-Jcog). We studied 79 patients with mild AD, 46 with MCI and 34 normal controls. The sensitivity and specificity of each test in the diagnosis of AD and MCI were compared. The average total TYM-J scores were 45.7 in controls, 41.7 in MCI, and 35.7 in AD. The TYM-J scores showed good correlations with other neuropsychological tests. The receiver operating characteristic analysis demonstrated that the TYM-J could better discriminate AD from controls and MCI from controls than the other tests. With each optimal cut-off score of the TYM-J, the sensitivity and specificity were 96% and 91% for diagnosing AD, and 76% and 74% for diagnosing MCI, respectively. The TYM-J is useful for the diagnosis of AD and MCI, and can be applied as a screening test in a Japanese memory clinic.     

Screening for mild cognitive impairment (MCI) utilizing combined mini-mental-cognitive capacity examinations for identifying dementia prodromes

OBJECTIVE: To test correctness of results when combining Mini-Mental State Examination (MMSE) and Cognitive Capacity Screening Examination (CCSE) for identifying mild cognitive impairment (MCI) among non-demented elderly subjects at risk for developing dementia. METHODS: A retrospective study was conducted among consecutively referred volunteers with memory complaints to a research out-patient clinic. Two cognitive screening tests (MMSE and CCSE) were performed according to established protocol. Resulting combined screening test (termed by acronym as CMC) combined the non-overlapping test items derived from both MMSE and CCSE. Conversion to dementia at follow-up served as the 'gold-standard' for evaluating correctness of CMC for identifying MCI. RESULTS: Of 351 subjects completing cognitive assessments and meeting requirements for study protocol, 84 (23.9%) developed dementia of different types within 3-6 years (3.89 +/- 2.17) of follow-up. Among these, 47 met criteria for probable Alzheimer disease (AD), 22 for probable vascular dementia (VaD), 12 for mixed AD/VaD and three for probable frontotemporal dementia. When final diagnosis of AD was used as the 'gold standard' for testing correctness of MCI identified by cognitive screening tests, sensitivities of MMSE, CCSE and CMC for identifying MCI were relatively 61.0%, 74.3% and 83.1% with minimum specificity set at 80%. When diagnosis of all types of dementia was used as the standard for testing predictive correctness of MCI, CCSE emerged as an optimal MCI screening test. CONCLUSION: Combining the CCSE and MMSE screening tests resulted in higher sensitivity than was achieved by MMSE alone and maintained specificity at comparable levels for identifying MCI. The results confirmed that CMC has optimal correctness and utility as a brief cognitive test for screening MCI as a prodrome for dementia among non-demented elderly populations.     

轻度认知损害患者的空间结构能力障碍

目的 研究轻度认知损害(mild cognitive impairment,MCI)患者空间结构能力的缺损与保持状况.方法 将被试者分为3组:健康对照组122名,其中男51名、女71名;MCI组205例,男95例、女110例,其中遗忘型MCI(aMCI)133例,非遗忘型MCI(naMCI)72例;阿尔茨海默病(AD)组75例,男36例、女39例.全部进行Rey-Osterrieth复杂图形测验(CFT)、画钟测验(CDT)、搭火柴测验3个结构能力测验,同时完成简易精神状态量表(MMSE)等测验.健康对照组、MCI组和AD组MMSE平均得分分别为28.24±1.74、27.39±1.83和19.98±3.23.采用SPSS for windows 11.5统计软件,计数资料采用卡方检验,3组间比较采用One-way方差分析,然后采用Bonferroni(LSD)法进行多重比较.结果(1)以健康组为对照,CFT模仿得分和CDT总分与年龄、教育年限没有显著相关性,搭火柴测验-旋转部分(STR)与年龄有相关性(r=-0.179,P＜0.05),与教育年限没有显著相关性.(2)CFT模仿得分与CDT总分(r=0.337)、STR(r=0.232),CDT总分与STR(r =0.235),均有显著相关性(均P＜0.01).(3)CFr模仿和CDT总分分别与反映执行功能的连线测验B、Stroop色词测验卡片C耗时数的相关性最高,而STR与反映记忆的指标听觉词语学习测验的相关性高.CFT模仿、CDT总分和STR在健康对照组、MCI组和AD组之间差异有统计学意义.(4)在识别MCI方面,经过对3组结构测验表现的比较得出STR优于CFT模仿、CDT总分.结论 结构能力损害是MCI的表现之一,空间旋转能力的评估在识别MCI方面优于CFT模仿、CDT总分.     

Utilidad diagnóstica de test cognitivos breves en el cribado de deterioro cognitivo

Introduction and objectivesThis study aims to assess and compare the diagnostic performance of brief cognitive tests for cognitive impairment (CI) screening recommended by the Spanish guidelines for the integral care of people with Alzheimer's disease and other dementias.Material and methodsWe performed a phase iii study into the accuracy of diagnostic tests, including patients with suspected CI in a primary care setting. All patients completed the Mini–Mental State Examination (MMSE), the Mini Examen Cognoscitivo (MEC), the Short Portable Mental Status Questionnaire (SPMSQ), the Memory Impairment Screen (MIS), the Clock Drawing Test (CDT), the Eurotest, the Fototest, and the Memory Alteration Test (M@T). CI was diagnosed independently by researchers blinded to scores on these tests. Diagnostic performance was evaluated by calculating the area under the receiver operating characteristic curve (AUC).ResultsThe study included 141 individuals (86 with CI). The Eurotest and M@T (AUC ± SE: 0.91 ± 0.02 and 0.90 ± 0.02, respectively) took longer to administer (mean [SD]: 7.1 [1.8] and 6.8 [2.2] min, respectively) and have significantly better diagnostic performance compared to the MMSE, MEC, SPMSQ, and CDT, but not compared to MIS or Fototest (both with an AUC of 0.87 ± 0.03), with the latter taking less than half as long to administer (2.8 [0.8] min). The M@T and MIS only evaluate memory, and the latter cannot be administered to illiterate people.ConclusionThe most advisable tests for CI screening in primary care are the Eurotest, M@T, and Fototest, with the latter being the most efficient as it takes half as long to administer.     

Brief informant screening test for mild cognitive impairment and early Alzheimer's disease

BACKGROUND/AIMS: Recent research has attempted combinations of instruments to improve screening accuracy for mild cognitive impairment (MCI) and early Alzheimer's disease (AD). We compared Mini-Mental State Examination (MMSE), Immediate and Delayed Recall (Logical Memory I and II; LM-I and LM-II, respectively), a single-item informant report of memory problem (IRMP), and a four-item Instrumental Activities of Daily Living (4IADL) scale, and combinations of these tests. METHOD: The tests were administered together with Clinical Dementia Rating (CDR) to subjects who were cognitively intact (CDR = 0, n = 88), and with diagnoses of MCI (CDR = 0.5, n = 37) and early AD (CDR = 1-2, n = 19). RESULTS: Screening accuracy (receiver operating characteristic area under curve, AUC) for identifying MCI or MCI-AD was lowest for MMSE (AUC 67.6% for MCI or 77.9% for MCI-AD), and better for IRMP (79.5 or 83.2%), 4IADL (76.9 or 84.7%), LM-I (81.2 or 87.1%) and LM-II (86.1 or 90.8%). Combining IRMP, 4IADL and LM-II was most accurate (AUC 91.7% for MCI or 94.5% for MCI-AD); sensitivity: 86.5 or 89.3%; specificity: 86.4 or 88.6%. However, combining IRMP and 4IADL gave nearly as good accuracy (AUC 87.2 or 91.6%); sensitivity: 86.5 or 85.7%; specificity: 79.5 or 85.2%. CONCLUSION: A brief instrument combining an IRMP and 4IADL items is potentially useful in screening for MCI and early AD.     

The relevance of hippocampal subfield integrity and clock drawing test performance for the diagnosis of Alzheimer’s disease and mild cognitive impairment

Objectives: The clock drawing test (CDT) is one of the worldwide most used screening tests for Alzheimer’s disease (AD). MRI studies have identified temporo-parietal regions being involved in CDT impairment. However, the contributions of specific hippocampal subfields and adjacent extrahippocampal structures to CDT performance in AD and mild cognitive impairment (MCI) have not been investigated so far. It is unclear whether morphological alterations or CDT score, or a combination of both, are able to predict AD.

Methods: 38 AD patients, 38?MCI individuals and 31 healthy controls underwent neuropsychological assessment and MRI at 3 Tesla. FreeSurfer 5.3 was used to perform hippocampal parcellation. We used a collection of statistical methods to better understand the relationship between CDT and hippocampal formation. We also tested the clinical feasibility of this relationship when predicting AD.

Results: Impaired CDT performance in AD was associated with widespread atrophy of the cornu ammonis, presubiculum, and subiculum, whereas MCI subjects showed CDT-related alterations of the CA4-dentate gyrus and subiculum. CDT correlates in AD and MCI showed regional and quantitative overlap. Importantly, CDT score was the best predictor of AD.

Conclusions: Our findings lend support for an involvement of different hippocampal subfields in impaired CDT performance in AD and MCI. CDT seems to be more efficient than subfield imaging for predicting AD.     

Diagnostic accuracy of the Phototest for cognitive impairment and dementia in Argentina

Phototest is a simple, easy and very brief test with theoretical advantages over available dementia screening tests in Spain. The objective of this study was to estimate the diagnostic accuracy of the Phototest for cognitive impairment and dementia and to compare it with that of the MMSE and the Clock Drawing Test (CDT) in an Argentine population. A phase II cross-sectional study of diagnostic tests evaluation was performed in a sample of 30 controls, 61 with amnestic mild cognitive impairment (a-MCI), and 56 with mild Alzheimer type dementia (DAT). The diagnostic accuracy (DA) was assessed in relation to the clinical diagnosis by calculating the area under the ROC curve (UAC), Sensitivity (Sn), and Specificity (Sp).The DA of the Phototest for a-MCI and DAT (0.93 and 0.97 [UAC]) was higher than that of the MMSE and the CDT. The cut-off points of 27/28 for DAT (Sn = 89.29 [78.1–96.0], Sp = 96.67 [82.8–99.9]) and 30/31 for a-MCI (Sn = 85.25 [73.8–93.0], Sp = 90.00 [73.5–97.9]) maximized the sum of Sn and Sp. Phototest correlates significantly with MMSE and CDT. The Phototest is an efficient instrument for the detection of mild dementia or MCI, with good accuracy and good correlation with tests measuring overall cognitive impairment.     

Markers of Alzheimer's disease in a population attending a memory clinic

BackgroundNew marker-based criteria for the diagnosis of Alzheimer's disease (AD) were recently proposed. We describe their operational translation in 144 consecutive patients referred to our Memory Clinic.MethodsVisual ratings of hippocampal atrophy and of cortical glucose hypometabolism in magnetic resonance imaging and positron emission tomography, and concentrations of total tau and Aβ1-42 in cerebrospinal fluid were assessed in 12 patients with subjective memory complaints (SMCs) (Mini-Mental State Examination [MMSE] score, 28.0 ± 1.1 [mean ± SD]), 37 with mild cognitive impairment (MCI) (MMSE, 25.1 ± 3.6), 55 with AD (MMSE, 21.1 ± 3.5), and 40 with non-AD dementia (MMSE, 21.6 ± 5.5).ResultsThe sensitivity for AD of each individual biomarker was higher (65% to 87%) than for MCI (18% to 50%). Each biomarker's specificity for SMC and non-AD dementias was good to moderate (83% and 53%). Positivity for at least one marker increased the probability 38 times of belonging to the AD group (P < 0.0001).ConclusionThe new diagnostic criteria can be operationalized in clinical routines, but longitudinal studies of MCI patients will need to assess the criteria's prognostic value.     

Relevance of 10-min delayed recall in dementia screening

Within the context of early diagnosis of Alzheimer's disease (AD), there is a growing interest in neuropsychological screening tests. Amongst these tests, we focused on the largely used Memory Impairment Screen (MIS). The objective of the present work was to show that adding a 10-min delayed recall to the MIS, improves the test psychometric characteristics in order to detect dementia in the earliest stages. A prospective study was carried out on a cohort of 270 consecutive elderly ambulatory subjects attending the Broca Hospital Memory Clinic: normal controls ( n  = 67), mild cognitive impairment subjects ( n  = 98) and mildly demented patients [ n  = 105, Mini Mental State Examination (MMSE) = 23 ± 4]. This study consisted in testing the advantage of the 10-min delayed recall entitled MIS-D compared with the MIS. At a cut-off score of 6, the MIS-D revealed satisfying psychometric characteristics with a sensitivity of 81% and a specificity of 91%, whilst the MIS alone indicated a sensitivity of 60% and a specificity of 88% in detecting dementia. In demented patients with MMSE score ≥26, MIS-D properties still remained satisfying (sensitivity: 75%, specificity: 92%). MIS-D is a more relevant screening test than MIS alone at very early stages of dementia.     

Discriminative capacity and construct validity of the Clock Drawing Test in Mild Cognitive Impairment and Alzheimer’s disease

Abstract

Objectives: The aim of this study was to analyze the psychometric and diagnostic properties of the Clock Drawing Test (CDT), scored according to the Babins, Rouleau, and Cahn scoring systems, for Mild Cognitive Impairment (MCI) and Alzheimer’s disease (AD) screening, and develop corresponding cutoff scores. Additionally, we assessed the construct validity of the CDT through exploratory and confirmatory factor analysis.

Methods: We developed a cross-sectional study of ambulatory MCI and AD patients, divided in two clinical groups (450?MCI and 250 mild AD patients) and a normal control group (N?=?400). All participants were assessed with the CDT, Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) for convergent validity.

Results: The selected scoring systems presented adequate validity and reliability values. The proposed cutoff scores showed 60 to 65% sensitivity and 58 to 62% specificity to identify MCI patients. The corresponding values for AD were 84 to 90% sensitivity and 76 to 78% specificity. Exploratory and confirmatory factor analysis revealed that the Babins scoring system had good construct validity and allowed us to propose a three-factor model for this system.

Conclusions: Our results confirmed the complexity of the CDT and support it as a cognitive screening instrument particularly sensitive to AD. The use of the CDT with MCI patients should be interpreted with more caution due to the lower sensitivity and specificity for milder forms of cognitive impairment.     

Clinical application of the Polish adaptation of the Montreal Cognitive Assessment (MoCA) test in screening for cognitive impairment

Background and purposeThe Montreal Cognitive Assessment (MoCA) test is a brief cognitive screening tool with high sensitivity and specificity for detecting mild cognitive impairment (MCI). The aim of this study was to evaluate the usefulness of MoCA and compare it with the Mini-Mental State Examination (MMSE) in the early detection of cognitive decline in MCI.Material and methodsA group of 115 subjects (36 meeting DSM-IV criteria for Alzheimer disease (AD) [Clinical Dementia Rating (CDR) = 1], 42 meeting Petersen's criteria for MCI [CDR = 0.5], and 37 cognitively intact controls [CDR = 0]) was recruited for the study in the university-based Alzheimer out-patient clinic. All participants underwent general medical, neurological, and psychiatric examinations. The MoCA, the MMSE, CDR and the short (15-item) version of the Geriatric Depression Scale were also applied.ResultsBoth MCI and AD groups exhibited impaired performance on MoCA compared to controls. Polish versions of the MMSE and MoCA tests were comparable in discriminating mild dementia from both MCI and control groups. The Polish version of the MoCA test performed marginally better than MMSE in discriminating MCI from controls. We propose to use the MoCA test to screen for MCI using an optimal cut-off score of 24 and to screen for dementia using a cut-off score of 19.ConclusionsThe Polish version of the MoCA seems effective in the detection of deteriorated cognitive performance and appropriate for differentiating impaired from preserved cognitive function in a Polish population.     

A preliminary study of the Six-Item Screener in detecting cognitive impairment

Objective

The present retrospective study was to explore the clinical value of Six-Item Screener (SIS), which is constituted by 6 items from mini-mental status examination (MMSE), to identify cognitive impairment.

Methods

A total number of 1976 patients aged over 50 years, from the Memory Clinic of Huashan Hospital were employed in a battery of neuropsychological tests including MMSE. Subjects with severe conditions, unable to cooperate, or having been previously enrolled, were excluded from this study. The employed subjects were divided into 3 groups: subjective memory complaints (SMCs) (475 cases), patients with mild cognitive impairment (MCI) (440 cases), and patients with Alzheimer’s disease (AD) (1061 cases, including 555 mild, 339 moderate, and 167 severe). A total score of MMSE and a score of SIS composed of date, month, year, three-word delayed recall from MMSE were calculated. Data were analyzed based on educational background.

Results

The cut-off of SIS score was ⩽ 2 for illiterate, ⩽ 3 for elementary, and ⩽ 4 for junior high school or above. The sensitivity and specificity of SIS for detecting mild AD were 88.5% and 78.3%, respectively, with an overall accuracy of 83.8%, while for detecting MCI, the sensitivity and specificity were 34.3% and 90.1%, respectively, with an overall accuracy of 63.2%.

Conclusion

SIS is an effective and reliable instrument for dementia detection in outpatient department. However, it has limited value for MCI identification.     

Loss of nucleus basalis neurons containing trkA immunoreactivity in individuals with mild cognitive impairment and early Alzheimer's disease

Recent studies indicate that there is a marked reduction in trkA-containing nucleus basalis neurons in end-stage Alzheimer's disease (AD). We used unbiased stereological counting procedures to determine whether these changes extend to individuals with mild cognitive impairment (MCI) without dementia from a cohort of people enrolled in the Religious Orders Study. Thirty people (average age 84.7 years) came to autopsy. All individuals were cognitively tested within 12 months of death (average MMSE 24.2). Clinically, 9 had no cognitive impairment (NCI), 12 were categorized with MCI, and 9 had probable AD The average number of trkA-immunoreactive neurons in persons with NCI was 196, 632 +/- 12,093 (n = 9), for those with MCI it was 106,110 +/- 14,565, and for those with AD it was 86,978 +/- 12,141. Multiple comparisons showed that both those with MCI and those with AD had significant loss in the number of trkA-containing neurons compared to those with NCI (46% decrease for MCI, 56% for AD). An analysis of variance revealed that the total number of neurons containing trkA immunoreactivity was related to diagnostic classification (P < 0.001), with a significant reduction in AD and MCI compared to NCI but without a significant difference between MCI and AD. Cell density was similarly related to diagnostic classification (P < 0.001). There was a significant correlation with the Boston Naming Test and with a global score measure of cognitive function. The number of trkA-immunoreactive neurons was not correlated with MMSE, age at death, education, apolipoprotein E allele status, gender, or Braak score. These data indicate that alterations in the number of nucleus basalis neurons containing trkA immunoreactivity occurs early and are not accelerated from the transition from MCI to mild AD.     

Relationship between clock drawing test performance and regional cerebral blood flow in Alzheimer's disease: a single photon emission computed tomography study

The clock drawing test (CDT) is a useful tool for screening cognitive impairment. Previous neuropsychological studies have revealed that CDT performance requires several cognitive functions including semantic memory, visuospatial function and executive function. However, the neural substrates involved remain to be elucidated. The aim of the present study was to identify the brain regions responsible for CDT performance in patients with Alzheimer's disease (AD). Twenty-six patients satisfying the National Institute of Neurological and Communicative Disease and Stroke-Alzheimer's Disease and Related Disorders Association criteria for probable AD underwent the CDT and the Mini-Mental State Examination (MMSE), together with a N-isopropyl-p-[123I] iodoamphetamine (IMP) single photon emission computed tomography measurements of the resting regional cerebral blood flow (rCBF). The CDT score correlated significantly with the MMSE score (r=0.582; P < 0.05). Stepwise multiple regression analysis revealed that the MMSE score and the left posterior temporal rCBF were major predictors of CDT score. These findings suggest that the CDT score may reflect the severity of dementia, and that it has a close relationship with the left posterior temporal function. Our findings provide the first functional neuroimaging evidence for the neural substrates involved in CDT performance.     

Comparative accuracies of two common screening instruments for classification of Alzheimer's disease,mild cognitive impairment,and healthy aging

BackgroundThe aim of this study was to compare the utility and diagnostic accuracy of the Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE) in the diagnosis of Alzheimer's disease (AD) and mild cognitive impairment (MCI) in a clinical cohort.MethodsThree hundred twenty-one AD, 126 MCI, and 140 older adults with healthy cognition (HC) were evaluated using the MMSE, the MoCA, a standardized neuropsychologic battery according to the Consortium to Establish a Registry of Alzheimer's Disease (CERAD-NB), and an informant-based measure of functional impairment, the Dementia Severity Rating Scale (DSRS). Diagnostic accuracy and optimal cut-off scores were calculated for each measure, and a method for converting MoCA to MMSE scores is presented.ResultsThe MMSE and MoCA offer reasonably good diagnostic and classification accuracy as compared with the more detailed CERAD-NB; however, as a brief cognitive screening measure, the MoCA was more sensitive and had higher classification accuracy for differentiating MCI from HC. Complementing the MMSE or the MoCA with the DSRS significantly improved diagnostic accuracy.ConclusionThe findings support recent data indicating that the MoCA is superior to the MMSE as a global assessment tool, particularly in discerning earlier stages of cognitive decline. In addition, we found that overall diagnostic accuracy improves when the MMSE or MoCA is combined with an informant-based functional measure. Finally, we provide a reliable and easy conversion of MoCA to MMSE scores. However, the need for MCI-specific measures is still needed to increase the diagnostic specificity between AD and MCI.