画钟测验对轻度阿尔茨海默病的诊断作用

目的 探讨画钟测验（CDT）对诊断轻度阿尔茨海默病（AD）患者的敏感度和特异度.方法 轻度AD患者40例,正常对照40例,对所有受试者进行CDT检测,评分采用5分法.应用操作者特征性曲线（ROC）确定CDT对诊断轻度AD的最佳分界值以及诊断的敏感度和特异度.结果 患者组和正常对照组的年龄、性别和教育程度匹配.应用5分评定法,CDT鉴别正常老人和轻度AD的最佳分界值为4分,此时敏感度和特异度分别为90.0%和82.5%.结论 CDT是识别轻度AD患者的一种有效筛查手段.     

The three-item clock-drawing test: a simplified screening test for Alzheimer's disease

The Clock-Drawing Test (CDT) has been used to screen for Alzheimer's disease (AD) as a supplement to cognitive tests that focus on memory impairment. We examined a comprehensive scoring system of the CDT in screening of AD in a Chinese population and derived a simplified scoring system. All 403 (144 AD and 259 nondemented) subjects were administered the CDT, including both the drawing part (CDT-D) and the copying part (CDT-C). The Cognitive Abilities Screening Instrument and the Clinical Dementia Rating were also administered. Stepwise discriminant analysis was used to develop a simplified CDT scoring system. The optimal CDT cutoff scores (CDT-D: 10/11; CDT-C: 12/13) show intermediate sensitivity (CDT-D: 66.7%; CDT-C: 51.4%) and specificity (CDT-D: 74.5%; CDT-C: 74.1%). The simplified 3-item CDT scoring system, with a cutoff score of 2/3, has a sensitivity of 72.9% and a specificity of 65.6%; it can be used as a quick test for AD screening.     

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.     

The value of the clock drawing test and the mini-mental state examination for identifying vascular cognitive impairment no dementia

OBJECTIVE: To determine the validity of the Clock Drawing Test (CDT) and the Mini-Mental State Examination (MMSE) respectively or in combination for differentiating Vascular Cognitive Impairment No Dementia (V-CIND) from normal subjects. METHODS: Eighty V-CIND patients and 80 healthy control subjects were blindly evaluated with MMSE, CDT, and additional neuropsychological tests. CDT was scored according to the Rouleau method and AD Cooperative Study method. Sensitivities and specificities of the two CDT measures and MMSE for identifying V-CIND patients were determined. The Areas Under the Receiver Operating Characteristic Curve (AUCs) were compared, and the sensitivity of the combination of CDT with MMSE calculated. RESULTS: V-CIND group performed worse than controls on both MMSE (p < 0.0001) and the two CDTs (p < 0.0001). In differentiating V-CIND patients from normal subjects, the two CDT measures provided sensitivities of 68.7% and 65.0%, and specificities of 78.7% and 86.2% respectively at optimal cutoff scores, which did no better than MMSE (sensitivity 80%, specificity 70%) (comparison of the AUCs, p = 0.992 and 0.428). The sensitivity of MMSE was marginally higher than that of CDT scored with AD Cooperative Study method (p = 0.053). By combining the two CDT measures with MMSE, the sensitivity was improved to 93.7% and 92.5% respectively. CONCLUSIONS: Compared with MMSE, CDT is of only similar or even weaker ability for identifying V-CIND. MMSE at a cutoff of 28 may be of some value in detecting V-CIND patients. CDT and MMSE in combination provide a valid instrument for V-CIND screening.     

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.     

Validity of the montreal cognitive assessment (MoCA) as a screening test for mild cognitive impairment (MCI) in a cardiovascular population

While rates of mild cognitive impairment (MCI) are relatively high in populations with cardiovascular diseases and risk factors, screening tests for MCI have not been evaluated in this patient group. This study investigated the sensitivity and specificity of the Montreal Cognitive Assessment (MoCA) tool for detecting MCI in 110 patients (mean age 67.9 + 11.7 years; 60% female) recruited from hospital cardiovascular outpatient clinics. Mean MoCA performance was relatively low (22.8 + 3.8) in this group, with 72.1% of participants scoring below the recommended cutoff for cognitive impairment (<26). The presence of MCI was determined using the Neuropsychological Assessment Battery Screening Module (NAB-SM). Both amnestic MCI and multiple-domain MCI were identified. The optimum MoCA cutoff for detecting MCI in this group was <24. At this cutoff, the MoCA's sensitivity for detecting amnestic MCI was 100% and for multiple-domain MCI it was 83.3%. Specificity rates for amnestic MCI and multiple-domain MCI were 50.0% and 52% respectively. The poor specificity of the MoCA suggests that it will have limited value as a screening test for MCI in settings where the overall prevalence of MCI is low.     

Validating the DemTect with 18-fluoro-2-deoxy-glucose positron emission tomography as a sensitive neuropsychological screening test for early alzheimer disease in patients of a memory clinic

OBJECTIVES: The first study to validate the diagnostic value of the DemTect, a short neuropsychological screening test for dementia (8-10 min), using 18-fluoro-2-deoxy-glucose positron emission tomography (FDG-PET) in patients of a memory clinic. METHODS: DemTect results were compared to the clinical diagnosis and to FDG-PET as a reference method for the early in vivo detection of Alzheimer's disease (AD). Results: 38 patients (age 65.2 +/- 9.8 years, 16 men, 22 women) were investigated using clinical standard examination, FDG-PET, and cranial magnetic resonance imaging. According to NINCDS-ADRDA and Petersen's criteria, 18 patients had dementia of the Alzheimer type (DAT) and 13 patients received the diagnosis of mild cognitive impairment (MCI). Compared to the clinical diagnosis, a DemTect cutoff score of < or =11 points demonstrated good sensitivity (83.3%) and specificity (70.0%) for the detection of DAT, whereas the best cutoff score for MCI was < or =13 points with comparable sensitivity (84.6%) and specificity (85.7%). With regard to FDG-PET, the DemTect demonstrated excellent sensitivity (93%) and low specificity (50%) for the detection of AD-typical patterns of cerebral glucose metabolism (cutoff < or =13 points). CONCLUSION: DemTect is a favorable neuropsychological screening instrument for detecting cognitive dysfunction even in predementia stages of AD. For definite cross-sectional diagnosis, further diagnostic evaluation with higher specificity, e.g. comprehensive neuropsychological examination, FDG-PET or other biomarkers, is necessary.     

Subjective memory complaints in Chinese subjects with mild cognitive impairment and early Alzheimer's disease

BACKGROUND: Mild cognitive impairment (MCI) represents a transitional state between normal aging and dementia. However, there is inconsistent opinion as to the validity of subjective memory complaints as a criterion for diagnosis. OBJECTIVE: This study aimed to examine the potential significance of applying a short memory questionnaire in the assessment of Chinese subjects with MCI and early dementia. METHODS: Three hundred and six ambulatory Chinese subjects were recruited. Each participant completed a short memory questionnaire. They were also assessed with the Chinese versions of the mini-mental state examination (CMMSE), Alzheimer's disease assessment scale-cognitive subscale (ADAS-Cog), category verbal fluency test (CVFT) and span tests. Severity of cognitive impairment was evaluated using the Clinical Dementia Rating (CDR); subjects with CDR 0.5 were further classified into MCI not demented (MCIND) and MCI possible incipient dementia (MCIID) depending on the subscale scores of CDR. RESULTS: An increasing frequency of memory complaints with increasing CDR was observed (Kruskal Wallis test, chi square = 21.29, df 3, p < 0.001). With a cutoff of 3 or more memory complaints, the memory questionnaire demonstrated a sensitivity of 65.3% and 70.4% in identifying subjects with incipient and early dementia respectively. Significant associations between memory complaints and most cognitive test performance were found (Spearman's correlations, p < 0.01). Logistic regression analysis revealed that educational level, the memory questionnaire, ADAS-Cog total and delayed recall scores were significant predictors of MCIID status. CONCLUSIONS: The findings suggested that a short memory questionnaire is useful in the screening of MCI, particularly in subjects who already present with subtle functioning disturbances. Subjective memory complaints were significant correlated with objective performance of memory functions, reflecting the usefulness of memory complaints in the assessment of MCI.     

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.     

Detection of memory impairment in the general population: screening by questionnaire and telephone compared to subsequent face-to-face assessment

BACKGROUND: Development of efficient methods for identifying subjects with Mild Cognitive Impairment (MCI) from the general population is warranted, because these subjects represent an important group for (epidemiological) research purposes. OBJECTIVES: (1) To describe a two-step population screening for identifying adults with MCI from the general population for research purposes, by questionnaire and telephone; (2) to compare screening by telephone (method 1) to a subsequent face-to-face assessment (method 2). METHODS: In method 1, subjects with memory complaints were identified from the general population (n = 5491) by a postal questionnaire. Subsequently, cognitive status and memory were assessed in a telephone interview using the Telephone Interview for Cognitive Status and the Ten Word Learning Test. Next, subjects with MCI according to method 1 were subjected to a face-to-face assessment for method 2, in which cognitive status and memory were assessed using the Mini Mental State Examination (MMSE) and the Auditory Verbal Learning Test (AVLT). RESULTS: Two hundred and twenty-seven subjects completed both the telephone interview and the face-to-face assessment. Ninety-three subjects (41%) had MCI according to both methods. Seven subjects (3%) failed to meet MCI criteria according to method two because of an MMSE score <24; 127 subjects (56%) failed because of normal AVLT scores. CONCLUSION: (1) The two-step population screening was able to detect a considerable number of MCI-subjects in the general population; (2) agreement between both methods was moderate. Therefore, the method of recruiting subjects for (epidemiological) studies has to be taken into consideration when interpreting results of these studies.     

The Montreal Cognitive Assessment: validity and utility in a memory clinic setting.

OBJECTIVE: To prospectively validate the Montreal Cognitive Assessment (MoCA) in a UK memory clinic. METHOD: We administered the MoCA and Mini-Mental State Examination (MMSE) to 32 subjects fulfilling diagnostic criteria for dementia, to 23 subjects fulfilling diagnostic criteria for mild cognitive impairment (MCI), and to 12 memory clinic comparison subjects, at baseline and then at 6-month follow-up. Clinical diagnoses for dementia and MCI were made according to ICD-10 and Petersen criteria. The sensitivity and specificity of both measures were assessed for detection of MCI and dementia. RESULTS: With a cut-off score of 26, the MMSE had a sensitivity of 17% to detect subjects with MCI, whereas the MoCA detected 83%. The MMSE had a sensitivity of 25% to detect subjects with dementia, whereas the MoCA detected 94%. Specificity for the MMSE was 100%, and specificity for the MoCA was 50%. Of subjects with MCI, 35% developed dementia within 6 months, and all scored less than 26 points on the MoCA at baseline. CONCLUSIONS: The MoCA is a useful brief screening tool for the detection of mild dementia or MCI in subjects scoring over 25 points on the MMSE. In patients already diagnosed with MCI, the MoCA helps identify those at risk of developing dementia at 6-month follow-up.     

Evaluation of a computerized test system to screen for mild cognitive impairment

Background: Mild cognitive impairment (MCI) refers to the clinical condition between normal aging and Alzheimer's disease (AD) and has a high probability of developing into AD. Early detection of MCI is important because early detection and appropriate follow‐up treatment can prevent the disease from progressing. Therefore, MCI is an important candidate for screening and possible intervention. Methods: We have developed a computerized screening test system to identify cognitive decline. This system consists of six tests (age and year‐of‐birth validity test, three‐word memory test, time orientation test, first modified delayed‐recall test, visual working memory test and second modified delayed‐recall test). The scores obtained from three groups (MCI patients, AD patients and healthy control subjects) were analyzed to evaluate the sensitivity and specificity required for the screening of MCI. Results: The system was well accepted by the patients. All of the test procedures were completed within 5 min. Significant group differences in all test results were found. The system has sensitivity and specificity values of 82% and 87%, respectively, when used as a screen for MCI. Conclusion: The system is useful for the screening of cognitive disorders.     

The clock drawing test as a screening tool in mild cognitive impairment and very mild dementia: a new brief method of scoring and normative data in the elderly

many studies sustained that the clock drawing test (CDT) was not able to accurately detect people with CDR = 0.5. Other researchers have promoted the use of scoring approaches with multiple scales that rate quantitative and qualitative features of the production. Nevertheless, these scoring systems are complex and time-consuming. We propose a new brief CDT’ scoring system in order to find a good measure for mild cognitive decline which is at the same time easy to administer. we enrolled 719 subjects: n. 181 with mild Alzheimer’s disease (AD); n. 200 with amnesic mild cognitive impairment (MCI) and n. 338 healthy elderly subjects (C). our CDT-three-cluster scoring system demonstrated a good sensitivity and an excellent specificity to discriminate MCI subjects from normal elderly (76 and 84 %, respectively) and an excellent sensitivity and specificity to discriminate patients affected by mild Alzheimer disease (CDR: 1) from normal elderly (91 and 90 %, respectively). We found that CDT’ score = 1.30 discriminate people with MCI, whereas a score = 4.38 discriminate AD patients. The three-cluster-scoring-system demonstrated a good diagnostic accuracy, taking into account those error-items more predictive of cognitive decline: omission of numbers or hands, writing numbers or hands in a wrong position and writing numbers or hands in a different code. Our CDT’ scoring system is very short and easy method which can be used also by non-specialist.     

The clock drawing test in primary care: sensitivity in dementia detection and specificity against normal and depressed elderly

OBJECTIVES: The aim of this study was to examine the sensitivities and specificities of the clock drawing test (CDT) in the detection of dementia among older people in primary care, with particular emphasis on the effect of depression on CDT specificity. Most previous studies have been sited in specialist settings and few have addressed the issue of specificity against depression. METHODS: Comparison of cohorts identified from community-based screening with GMS-AGECAT. The CDT and the Mini-Mental State Examination (MMSE) were administered to 41 elderly subjects with organic disorder (dementia), 84 elderly subjects with case level depression and 523 normal elderly subjects. Sensitivities and specificities of the CDT were calculated. RESULTS: The sensitivity of the CDT in the detection of dementia in the general community was 76%. The specificities of the CDT against normal elderly and depressed elderly was 81% and 77% respectively. Higher sensitivity and specificity were achieved by the MMSE. CONCLUSIONS: The use of the CDT in the detection of dementia syndromes is likely to be more relevant in the primary care context than in specialist settings. The CDT provides good sensitivity and specificity but may not be as sensitive or specific in the general community as previous studies have suggested, particularly in mild dementia. Community-based late life depression does not appear to alter the specificity of the CDT.     

Measuring mild cognitive impairment in patients with Parkinson's disease

We examined the frequency of Parkinson disease with mild cognitive impairment (PD‐MCI) and its subtypes and the accuracy of 3 cognitive scales for detecting PD‐MCI using the new criteria for PD‐MCI proposed by the Movement Disorders Society. Nondemented patients with Parkinson's disease completed a clinical visit with the 3 screening tests followed 1 to 3 weeks later by neuropsychological testing. Of 139 patients, 46 met Level 2 Task Force criteria for PD‐MCI when impaired performance was based on comparisons with normative scores. Forty‐two patients (93%) had multi‐domain MCI. At the lowest cutoff levels that provided at least 80% sensitivity, specificity was 44% for the Montreal Cognitive Assessment and 33% for the Scales for Outcomes in Parkinson's Disease‐Cognition. The Mini‐Mental State Examination could not achieve 80% sensitivity at any cutoff score. At the highest cutoff levels that provided specificity of at least 80%, sensitivities were low (≤44%) for all tests. When decline from estimated premorbid levels was considered evidence of cognitive impairment, 110 of 139 patients were classified with PD‐MCI, and 103 (94%) had multi‐domain MCI. We observed dramatic differences in the proportion of patients who had PD‐MCI using the new Level 2 criteria, depending on whether or not decline from premorbid level of intellectual function was considered. Recommendations for methods of operationalizing decline from premorbid levels constitute an unmet need. Among the 3 screening tests examined, none of the instruments provided good combined sensitivity and specificity for PD‐MCI. Other tests recommended by the Task Force Level 1 criteria may represent better choices, and these should be the subject of future research. © 2013 Movement Disorder Society     

画钟测验的评分方法探讨

目的 编制和验证画钟测验(CDT)新的评分方法.方法 对188名健康中老年人、170例轻度认知障碍(MCI)患者和81例轻度阿尔茨海默病(AD)患者进行CDT等一系列神经心理测验.CDT 30分法包括先锚定12-3-6-9 4个点,称为"30分法-A",共4分;反映画钟结果的其余13项,称为"30分法-C",共26分,总分30分.38例被试者完成氙-CT(Xe-CT)检查,定量测量脑26个区域的局部血流量(rCBF).结果 CDT 30分法的14个项目分与总分的相关系数r=0.48～0.71,均有显著的相关性(P＜0.01)."30分法-C"与空间知觉和执行功能指标的相关性较大(r=0.58～0.64),而"30分法-A"与记忆指标的相关性较大(r=0.67)."30分法-A"≤2分,识别MCI的敏感性为70.6%,特异性为73.9%,"30分法-C"≤17分,识别MCI的敏感性为38.2%,识别轻度AD的敏感性为75.3%,特异性为75.9%.CDT与Xe-CT检测的rCBF的关系:"30分法-A"和"30分法-C"的回归方程中,入选的自变量分别为左额叶下区和右白质区.结论 "30分法"A和C两部分具有不同的意义,"30分法-C"可用于识别AD,而"30分法-A"有助于MCI的识别.     

The use of amnestic and nonamnestic composite measures at different thresholds in the neuropsychological diagnosis of MCI

Both amnestic and nonamnestic deficits have been observed in patients with mild cognitive impairment (MCI). Most studies have focused on impairment on single cognitive tests rather than amalgamation of the results of several measures to arrive at a composite impairment index. In this investigation, we examined 20 MCI patients diagnosed as prodromal Alzheimer's disease, AD (mean Mini-Mental State Examination, MMSE = 26.1; SD = 1.7) and determined the extent to which they could be differentiated from 70 normal elderly controls based on composite measures at 1.5-SD and 2.0-SD cutoffs for impairment. At the 1.5-SD cutoff, the median number of memory indices impaired in the MCI-AD group was 5 of 7, whereas at the 2.0-SD cutoff, the median number was 4 of 7. A median of 3 of 7 and 2 of 7 nonmemory indices were impaired at 1.5- and 2.0-SD cutoffs for impairment. Receiver operator characteristics (ROC) analyses indicated that the total number of memory tests impaired at 2.0 SD (sensitivity = 95.0%/specificity = 84.3%) and the composite measure of both impaired memory and nonmemory measures (sensitivity of 85.0%/specificity of 100%) had high levels of discrimination and may have utility as indices of early impairment as well as severity of MCI.     

Quantitative and qualitative analyses of the clock drawing test in mild cognitive impairment and Alzheimer disease: evaluation of a modified scoring system

The clock drawing test (CDT) has been used as a screening tool for identifying cognitive decline in individuals with Alzheimer disease (AD) and other dementias but has not been extensively evaluated for categorizing individuals with mild cognitive impairment (MCI). This study used both an established quantitative scoring system and a revised scoring method based on qualitative error criteria developed by Rouleau et al to demonstrate the sensitivity of the CDT to MCI. Participants were 66 cognitively healthy older adult, 33 individuals with MCI, and 33 individuals with AD. Sensitivity analyses of the 2 clock drawing methods revealed that the Modified Rouleau scoring method was more sensitive to MCI than the original Rouleau scoring system. Conceptual, graphic, and spatial-planning difficulties were the most commonly committed errors on the CDT across all groups, and conceptual errors along with graphic difficulties were committed more often in the MCI group than the cognitively healthy control group. Participants in the AD group exhibited greater deficits in all error categories and significantly lower total CDT scores compared to both the MCI and older adult controls. Findings observed in this study suggest that qualitative observations of clock drawing errors can help increase sensitivity of the CDT to MCI and that use of a more detailed scoring system is necessary to differentiate individuals with MCI from cognitively healthy older adults.     

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.     

EEG detection of early Alzheimer's disease using psychophysical tasks.

In this study, we hypothesized that a quantitative EEG (qEEG) method for measuring EEG variability combined with specific psychophysical tasks could improve the classification accuracy of subjects with normal aging vs. mild cognitive impairment (MCI) or mild dementia due to Alzheimer's Disease and Related Disorders (ADRD). The cross-sectional sample consisted of 48 subjects (32 normal aging and 16 ADRD: n = 3 mild dementia, n = 13 MCI FAST stage 3). During EEG recording, subjects performed two visual, delayed recognition memory tasks as well as a task that tested their ability to perceive structure-from-motion (SFM). These EEG data were used to compute qEEG measures of the (normalized) variance of posterior cortical activity during the first 150 milliseconds (ms) after stimulus onset and the variance of anterior cortical activity during the second 150 ms epoch. The ratio, anterior/posterior cerebral qEEG value, was then computed for each subject, and the optimal cutoff value identified to discriminate normal from impaired subjects. An optimal qEEG cutoff value for the delayed recognition memory tasks correctly discriminated 30 of the 32 normal aging subjects (94% specificity) and 14 of 16 MCI-to-mild ADRD subjects (88% sensitivity). On the other hand, the application of this qEEG measure to EEG data recorded while subjects performed a SFM task did not distinguish between ADRD and normal aging any better than chance. In conclusion, this qEEG measure is specific to the psychophysical task being performed by the subject. When it was combined with delayed recognition memory tasks, it yielded results that are comparable to the accuracies reported by PET scan studies of normal aging vs. AD with mild cognitive impairment. These results warrant further evaluation.