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.     

Scoring clock tests for dementia screening: a comparison of two scoring methods

OBJECTIVE: To compare the dementia screening performance of two scoring systems of the clock drawing test. METHODS: A sample of 1199 elderly subjects was administered the clock drawing test as part of a study on aging and dementia. The clock drawings were scored using published criteria for the two scoring systems that were compared. Additionally, a selection of 103 drawings was scored by three different raters to evaluate inter-rater agreement within each of the two methods. For a selection of 473 drawings the final diagnosis on the presence or absence of dementia was known. For these drawings accuracy for the detection of dementia was compared between the two methods. RESULTS: The four-item scoring system (Kappa 0.76; sensitivity 0.97; specificity 0.32; PPV 0.53; NPV 0.93) was found to be a little more reliable and as accurate as the six-item scoring system (Kappa 0.67; sensitivity 0.96; specificity 0.42; PPV 0.56; NPV 0.94). CONCLUSION: Since both scoring systems showed largely similar results, primary care physicians and other health care providers should be encouraged to use the four-item scoring checklist as it is easier and requires less time than the more elaborate checklist of the six-item system.     

The utility of the clock drawing test in detection of delirium in elderly hospitalised patients

Objectives: Delirium is common neuropsychiatric condition among elderly inpatients. The clock drawing test (CDT) has been used widely as bedside screening tool in assessing cognitive impairment in elderly people. Previous studies which evaluate its usefulness in delirium reported conflicting results. The objective of this study was to evaluate the utility of CDT to detect delirium in elderly medical patients.

Method: Prospective, observational, longitudinal study. All acute medical admissions 70 years of age and above were approached within 72 hours of admission for recruitment. Patients eligible for inclusion were assessed four times, twice weekly during admission. Assessment included Confusion Assessment Method (CAM), Delirium Rating Scale (DRS-98R), Montreal Cognitive Assessment (MoCA), Acute Physiology and Chronic Health Evaluation II (APACHE) II, and CDT. Data was analysed using a linear mixed effect model.

Results: Three hundred and twenty-three assessments with the CDT were performed on 200 subjects (50% male, mean age 81.13; standard deviation: 6.45). The overall rate of delirium (CAM+) during hospitalisation was 23%. There was a significant negative correlation between the CDT and DRS-R98 scores (Pearson correlation r = ?0.618, p < 0.001), CDT and CAM (Spearman's rho = ?0.402, p < 0.001) and CDT and total MoCA score (Pearson's r = 0.767, p < 0.001). However, when the data were analysed longitudinally controlling for all the factors, we found that cognitive function and age were significant factors associated with CDT scores (p < .0001): neither the presence nor the severity of delirium had an additional significant effect on the CDT.

Conclusion: CDT score reflects cognitive impairment, independently of the presence or severity of delirium. The CDT is not a suitable test for delirium in hospitalised elderly patients.     

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.     

Clock drawing test in mild and moderate dementia of the Alzheimer's type: a comparative and correlation study

OBJECTIVES: (a) To compare two different clock drawing tests (CDTs) in mild and moderate dementia of the Alzheimer's type (DAT); (b) To examine presumed correlation between these CDTs and some demographic, cognitive and activities of daily living (ADL) variables in mild and moderate DAT. METHODS: Cross-sectional study. Psychogeriatric outpatient clinic. 49 DAT patients, total; 26-mild, 23-moderate, mean age 77.8 and 80.6, respectively.Evaluations included the Mini-Mental State Examination (MMSE), the Cambridge Cognitive Examination (CAMCOG), the Instrumental Activities of Daily Living Scale (IADL), and a Basic Activities of Daily Living (BADL)-dressing subscale. Severity of dementia was determined with the Clinical Dementia Rating (CDR). Each clock was blindly scored by the same investigator, according to Shulman's and Freedman's methods. RESULTS: Mild and moderate DAT groups were similar in age, gender and education. Performance on Shulman's clock was similar between groups while moderate DAT subjects performed significantly worse on Freedman's clock compared to mild DAT patients. Both clocks correlated highly in mild and moderate DAT. CDT scores correlated significantly with age and education only in mild DAT. Neither clock correlated with ADLs in either stage of dementia severity. CDTs correlated with the MMSE score, and the CAMCOG score in mild DAT, and only with the CAMCOG score in moderate DAT. These correlations were still significant after controlling for age and education. CONCLUSIONS: Different aspects of cognition and dementia severity are reflected depending on how a clock drawing is scored. Some scoring systems may have greater sensitivity than others in monitoring progression of cognitive deterioration. Correlation between different CDTs and the variables studied (demographic, cognitive, ADLs), when present, is not ubiqitous and changes with the dementia severity.     

Qualitative analyses of clock drawings in Alzheimer's disease and vascular dementia

Although quantitative analyses of clock drawings (CD) have achieved widespread clinical use as a cognitive screening, little is known about the qualitative profiles of CD in Alzheimer's disease (AD) and vascular dementia (VD). To address this issue, the present study examined the significance of qualitative analyses of CD in AD and VD. Sixty-seven AD patients, 44 VD patients and eight controls underwent a clock drawing test and took the Mini-Mental State Examinations (MMSE). In the dementia groups, quantitative scores significantly decreased compared with controls and were significantly correlated with MMSE scores. Qualitative analysis demonstrated that in AD patients qualitative error patterns were stable and independent of severity. In contrast, in VD patients the frequency of graphic difficulties and conceptual deficit increased, while the frequency of spatial and/or planning deficit decreased, as severity worsened. In mild dementia groups the frequency of spatial and/or planning deficit was significantly higher in VD. In moderate dementia groups, the frequency of graphic difficulties was significantly higher in VD and the difference in the frequency of spatial and/or planning deficit seen in mild dementia disappeared. The present study suggests that qualitative analyses of clock drawings could demonstrate the neuropsychological profiles of AD and VD and their differences between these dementias.     

Comparing clock tests for dementia screening: naïve judgments vs formal systems—what is optimal?

BACKGROUND: Clock drawing tests (CDTs) vary in format, scoring, and complexity. Herein, we compared the dementia screening performance of seven CDT scoring systems and the judgements of untrained raters. METHODS: 80 clock drawings by subjects of known dementia status were selected, 20 from each of four categories (Consortium to Establish a Registry for Alzheimer's disease [CERAD] defined normal, mild, moderate, and severe abnormality). An expert rater scored all clocks using published criteria for seven systems. Additionally, 20 na?ve raters judged clocks as either normal or abnormal, without formal instructions. Clocks were then classified by drawers' dementia status for comparison of dementia detection across systems. RESULTS: Na?ve and formal CDT systems showed 90-100% agreement in CERAD normal, moderate and severe categories, but poor agreement (mean = 39%) for mildly impaired clocks. When CDT systems were compared for accurate dementia classification, the Mendez and CERAD systems correctly identified the greatest proportion of subjects (84-85%), and Wolf-Klein the smallest (58%). The better systems correctly identified> 70% of mildly demented individuals (CDR = 1). In contrast, medical records from patients' personal physicians correctly identified only 24% of the mildly demented. Strikingly, na?ve raters' CDT judgements were as effective as five of the seven CDT systems in dementia identification. CONCLUSIONS: While the Mendez system was the most accurate overall, it was not significantly better than CERAD, which had simpler scoring rules. Untrained raters discriminated normal from abnormal clocks with acceptable accuracy for community screening purposes. Results suggest that, if used, most CDT systems would improve personal physicians' dementia recognition in difficult to detect mildly demented subjects.     

画钟测验在认知功能测评中的作用

随着社会老龄化的进程,痴呆发病率逐年增高,简便、易行、敏感、特异的测查方法是重要的,对目前临床常用的画钟测验(CDT)在认知功能测评中的应用及意义作一综述.     

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.     

Around the clock surveillance: simple graphic disturbance in patients with hemispatial neglect carries implications for the clock drawing task

BACKGROUND: Drawing, and the clock drawing task in particular, is widely used as a diagnostic tool in the study of hemispatial neglect. It is generally assumed that the errors in graphic production, such as the misplacement of numbers, reflect a visuospatial deficit, and that drawing production itself (for example, producing the circle) is unimpaired. OBJECTIVES: To test this assumption by examining whether the production of simple circles is affected by neglect. METHODS: 16 right hemisphere stroke patients copied circles of various sizes and their drawings were measured for size accuracy. RESULTS: Patients with more severe neglect produced greater scaling errors, consistently drawing the circle smaller than the original. Errors were not in the horizontal axis alone--shrinkage occurred equally in both height and width axes. CONCLUSIONS: Neglect can co-occur with constructional difficulties that serve to exacerbate the symptoms presented. This should be taken into account in the assessment of even apparently simple drawing tasks.     

Depression and apathy affect functioning in community active subjects with questionable dementia and mild Alzheimer's disease

BACKGROUND: The relationships between apathy, depression and functional impairment in questionable dementia (QD) and Alzheimer's disease (AD) are complex. This study aimed to explore the interactions between severity of apathy, depression and functional performance; and to investigate the effects of apathy alone, depression alone and coexistence of apathy and depression on the functional performance in subjects with QD and AD. METHODS: One hundred ninety-five subjects with QD and 96 subjects with mild AD were recruited. Apathy and depression were rated using the Neuropsychiatric Inventory and functional disability was measured using the Disability Assessment for Dementia (DAD). RESULTS: Severity of apathy and depression symptoms were associated with poorer functional performance in QD and apathy was associated with poorer functional performance in AD. In QD, subjects with apathy, depression, or coexistence of apathy and depression had poorer functional performance than those with neither apathy nor depression. The coexistence of apathy and depression did not produce more severe functional disability than apathy alone or depression alone. In AD, subjects with apathy had poorer functional performance than those without apathy. Depression in the absence of apathy was not associated with more severe functional disability. CONCLUSION: Apathy and depression symptoms are common in the early course of AD. Apathy and depression had different effects on functional performances in the subjects with QD from those with AD.     

A comparison of clock and pentagon drawing in Alzheimer's disease

Clock drawing is described as a novel, easily administered bedside measure of cognitive function. We examined from 77 ambulant elderly persons meeting NINCDS criteria for Alzheimer's disease their drawings of clock faces and overlapping pentagons. Interrater reliability for two previously published scoring scales for clocks and a devised ordinal scale for overlapping pentagons was high. There was moderate correlation with their total scores on the CAMCOG and Mini Mental State Exam (MMSE). However, a considerable number of patients scored within the normal range on all three drawing scales. A third (23/77) on clock drawing demonstrated their only abnormality at setting the time to 10 to 11 instead of the requested 10 past 11. For the clock drawing test to be used as a rapid screening instrument for Alzheimer's disease in the community an accurately drawn clock face must include the correct position of the hands. The pentagon test either alone or in combination did not enhance the accuracy of the clock test.     

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.