The Clock Drawing Test: A Valid Screening Instrument for Dementia Detection in Low-Educated Patients?

Background/Aims: Conversion rates to dementia are known to be high for patients with mild cognitive impairment (MCI), but the diagnosis of MCI is very time-consuming. Since the Clock Drawing Test (CDT) is quick to administer, it will be of interest to compare the predictive validity of the CDT and of an MCI diagnosis for the diagnosis of dementia. Methods: In a sample of 384 individuals, CDT scores and the presence of MCI were assessed at baseline and then compared between individuals with an incident dementia diagnosis at follow-up and those without. Multivariate analyses, receiver operating characteristic analyses and values of sensitivity and specificity of the CDT were performed. Results: Individuals with incident dementia had significantly higher CDT scores at baseline than those without dementia. CDT was a significant predictor of incident dementia after adjusting for other factors. CDT reached a sensitivity of 68% and specificity of 65%. The area under the receiver operating characteristic curve of CDT was 0.70 and therefore slightly lower than for MCI diagnosis (0.78). Conclusions: Because of the only slightly lower predictive value of the CDT, its quick application and scoring compared to the MCI concept applied, it will be worthwhile to improve the CDT scoring system in order to increase the predictive validity in dementia.

Relationship between the expression of TNFR1-RIP1/RIP3 in peripheral blood and cognitive function in occupational Al-exposed workers: A mediation effect study

The clock drawing test (CDT) is widely used in clinical neuropsychological practice. However, its neuroanatomical correlates have not been well established. This study investigated the effects of theta burst stimulation (TBS) applied over different brain regions on CDT scores in patients with Alzheimer's disease (AD). The 10-20 positions F3, F4, T3, T4, TP3, TP4, P3, P4, as determined by a 10-20 positioning cap, were targeted. Excitatory intermittent TBS (iTBS) was given over the above-mentioned eight regions to ten AD patients and ten control subjects on separate days. CDT was administered at baseline (T0), during the 5min following the TBS (T1) and 60min after TBS (T2), with an inter-session interval of at least 4days. iTBS over TP4 and P4 transiently increased Rouleau CDT score in AD patients. When targeting TP4 and P4, mainly the area of the supramarginal/angular gyrus and the inferior parietal lobe, corresponding respectively to the Brodmann areas 40/39 and 7/40, are reached. iTBS thus seems able to modulate activity of the right posterior parietal cortex in AD patients performing the CDT. Our results provide physiological evidence that those parietal regions are functionally important for the execution of the Rouleau CDT. This finding suggests that CDT has reliable neuroanatomical correlates, and support the notion that this test can be used as a good marker of right parietal brain dysfunction. The present study also highlights the therapeutic potential of the induction of neuromodulatory effects using non-invasive brain stimulation techniques.

Screening for dementia of the alzheimer type in the community: The utility of the clock drawing test

BackgroundDetection of any form of cognitive impairment is challenging and the subjects have to undergo numerous evaluations and clinical tests. Hence, it would be of great importance to design a reliable and accessible procedure by which patients may get diagnosed for dementia remotely. The capability of the Clock Drawing Test (CDT)as an effective cognitive assessment tool has motivated us to develop an online diagnostic tool by leveraging artificial intelligence techniques.MethodDigital pen recordings of 3,263 normal subjects and 160 with dementia in the Framingham Heart Study (FHS) were collected, where all subjects have completed two analog clock drawings, one drawn on command and the other by copying. Using the idea of transfer learning, we first modified and trained a Convolutional Neural Network (CNN) pre‐trained on the ImageNet dataset to extract high level features of the CDT images, which generated a score associated with the likelihood of dementia for each patient. The proposed method integrates the scores of the CDT images and other demographic information. Therefore, the generated scores for both command and copy CDTs along with age were used to train a logistic regression model to classify individuals as demented or normal.ResultWe have evaluated the performance of the developed models by applying 5‐fold cross validation on the FHS dataset. On the test dataset, the model (modified pre‐trained CNN) based on command CDT images yielded an AUC of 0.81±0.043. The logistic regression model using age and the generated scores of command and copy CDTs, yielded an average AUC and average F1 score of 0.92±0.008 and 0.94±0.008, respectively.ConclusionOur method need not necessarily have access to digital biomarkers or clinical tests since the CDT can be completed using pen and paper, capturing the image using a smartphone. Hence, our method offers a cost‐effective and accurate screening tool to diagnose dementia and related diseases remotely.

Education Modulates the Impact of White Matter Lesions on the Risk of Mild Cognitive Impairment and Dementia

Evaluación de la utilidad diagnóstica y validez discriminativa del Test del Reloj y del Mini-Cog en la detección del deterioro cognitivo

Background: Mild cognitive impairment (MCI) was originally used to describe a transitional state between normal condition and dementia. Revised and extended definition of MCI has been proposed that covers a broader range of cognitive impairment, distinct from normal ageing and from Alzheimer’s disease. Despite the existence of reports regarding analyses of the Clock Drawing test (CDT) in Alzheimer’s disease and vascular dementia, those focusing on MCI subjects are still lacking. The purpose of this study was to assess the characteristics of CDT and compare the results of quantitative and qualitative analyses of CDT performance in patients with MCI. Materials and methods: Five hundred four consecutive patients with MCI (Korean versions of the Mini-Mental State Examination (K-MMSE)>23) were recruited for the study. All participants were examined by the K-MMSE, modified-MMSE (3MS) and the CDT. Quantitative scoring of the CDT was done by the Manos and Wu’s method. Qualitative error types of the CDT were classified as stimulus-bound response (SBR), conceptual deficit (CD), spatial and/or planning deficit (SPD), and perseveration error (PE) by Rouleau’s classification. We divided the subjects into two subgroups by the MMSE scores (lower cognitive function group, MMSE=24~26 vs. higher cognitive function group, MMSE=27~30) and compared the CDT scores and frequency of the error types between them. Results: The total scores in the CDT significantly correlated with the total scores of the K-MMSE, 3MS and the level of education. Of the errors in the CDT, SPD was the most frequent type of error (45.3%) in the total samples. The scores in the K-MMSE and 3MS in the patients having CD errors were lower compared with those of other types of error. The lower cognitive group made more CD error (32.9%) than that of the higher cognitive group (25.5%). Conclusion: Although the CDT cannot be used solely for clinical diagnosis of dementia, it provides useful cognitive information quantitative as well as qualitative ways, estimating the characteristics of MCI patients as a simple screening test.

The Clock Drawing Test (CDT) is a recognized and accepted instrument for the early diagnosis of dementia in the elderly. In a prospective study we evaluated the association between the results of this test and a broad range of clinical, functional and sociodemographic variables. The study was conducted on elderly patients hospitalized for rehabilitation following stroke or hip fracture (HF) in the geriatric ward of a university hospital in southern Israel. The administration of the CDT and its scoring system were adapted from Sunderland et al. and Wolfe-Klein et al. The study was conducted on all 425 elderly patients who were hospitalized during the study period and who were capable of completing the test. Stepwise multiple regression was used to evaluate the association between the results of the CDT and the other variables. The mean CDT score (+/- SD) for the entire study population was 7.8 +/- 2.5 and 145 patients (34%) had scores of 6 or below. Of the 41 variables that were tested, significant associations with the CDT were found for the following four variables only: the Folstein minimental test (beta = 0.447, p < 0.0001), the cognition value from the admission FIM (beta = 0.252, p < 0.0001), years of education (beta = 0.183, p = 0.0001), and the patient's age (beta = -0.075, p = 0.037). The total variance of the CDT explained by these four variables (Adjusted R2) was 0.554. We conclude that in the study population there was a significant proportion of patients with low CDT scores. This score, in this population, is influenced in particular by two other measures of cognitive function and by the formal level of education, together with a weaker effect of age.

The ongoing scientific debate regarding the association between physical function and cognitive impairment has focused mainly on global cognitive performance rather than specific cognitive functions tests and the importance of recognition of its associations and any factors that could play a role later in the prevention of such decline. This study examined the association between physical function, using handgrip strength (HGS) and Timed Up-and-Go test (TUGT), and executive function (EF), using Clock Drawing Test (CDT), among community-dwelling Egyptian elderly. A cross-sectional study was conducted in 5 social clubs in Cairo, Egypt and included a sample of 136 elderly males and females aged≥55 years old. All participants had their physical function assessed using TUGT, and measurement of HGS using a pneumatic hand-held dynamometer. Assessment of EF using CDT was also done. Higher CDT scores were significantly associated with both better HGS, and lower TUGT (OR = 3.77, and 0.65 respectively). This persisted even after adjustment for age and gender (OR = 2.56, and 0.71 respectively) and after further adjustment for weight, systolic blood pressure, education, smoking, hyperlipidemia, hypothyroidism, and physical activity (O.R. = 4.79, and 0.76 respectively). Adjustment for both male and female genders showed an association between physical (HGS and TUGT) and EF was stronger among men. A strong association between CDT score and both of HGS and TUGT was found among the studied sample. Higher HGS and lower TUGT was significantly associated with better performance in the CDT. This association is stronger in males than in females for both HGS and TUGT.

Comparing the Influences of Age and Disease on Distortion in the Clock Drawing Test in Japanese Patients With Schizophrenia

Wavelet transformation (WT) analyses were performed on Target/standard stimulus of P300 Event Related Potential (ERP) amongst low and high educational level personels to assay how the underlying electroencephalographic (EEG) activity affected them. 12 healthy subjects (6 in each group) were recruited for this study (low and high education groups). The high education group had significantly high amplitude in both standard and target stimuli at Pz location comparing low education group. The WT analyses indicated that high education group has significant alpha and delta wave signals during target stimuli than low education group. We concluded that education level modified brain signal activity which enhanced the decision making and surprise component.

An early and a quick identification of dementia is desirable to improve the overall care to the affected persons in the developing countries. The aim of this study was to evaluate the discriminative abilities of the Mini Mental State Examination (MMSE) and the Clock Drawing Test (CDT) in differentiating the demented patients from the controls and also the differentiation between the different types of dementia. This study was designed to evaluate the patients with varied types and severities of dementia, who were diagnosed by using the Clinical Dementia Rating (CDR) scale. All the patients completed the MMSE and the simplified CDT. This study included 197 patients with an age range of 43-79 years. Fifty-one patients (25.9%) were diagnosed with Alzheimer Dementia (AD), 37 patients (18.8%) with Vascular Dementia (VD), 23 patients (11.7%) with Parkinson's Disease Dementia (PDD) and 86 patients (43.6%) with other variants of dementia. The total MMSE score of the enrolled patients was significantly lower as compared to that of the control subjects, with a non-significant difference between the varied diagnoses. The total CDT scores were significantly lower in the patients as compared to those in the controls, with significantly lower scores in the PDD group as compared to those in the AD group. The patients who had AD showed non-significantly higher CDT scores as compared to the patients who had vascular and other types of dementia. A combined application of both MMSE and CDT can identify the persons with a cognitive affection and this may be a useful tool for the diagnosis of the non Alzheimer's type of dementia.

Objective: The Clock Drawing Test (CDT) is frequently used to screen for cognitive impairment, however, normative data for Rouleau et al.’s scoring system are scarce. The present study aims to provide norms for Rouleau et al.’s scoring system that are tailored to Quebec French-speaking mid- and older aged healthy adults.Methods: Six researchers from various research centers across the Province of Quebec (Canada) sent anonymous data for 593 (391 women) healthy community-dwelling volunteers (age range: 43–93 years; education range: 5–23 years) who completed the CDT ‘drawing on command’ version. This command version (setting the clock hands to 11:10, without a pre-drawn circle) was administrated as part of a more extensive neuropsychological assessment, or along with cognitive screening instruments. Each drawn clock was scored according to the quantitative criteria set by Rouleau et al.’s scoring system.Results: CDT scores were significantly correlated with age (r(592) = −.132, p = .001) and years of education (r(592) = .116, p = .005), but not with sex (r(592) = .065, p = .112). Since data were skewed towards higher test scores, the percentiles method was used for analysis. Percentile ranks stratified by age and education are presented.Conclusion: These normative data for Rouleau et al.’s scoring system will contribute towards adequately screening for cognitive decline in Quebec French-speaking healthy adults, by also taking into account individual characteristics such as age and education.

The effect of music by Mozart on cognitive performance and brain plasticity in elderly adults was explored. To the knowledge of the authors, this is the first study to provide documentary evidence of an increase in brain-derived neurotropic factor (BDNF) serum levels after exposure to Mozart’s music in human beings.