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

An Overview of Chemistry, Kinetics, Toxicity and Therapeutic Potential of Boldine in Neurological Disorders

Boldine is an alkaloid obtained from the medicinal herb Peumus boldus (Mol.) (Chilean boldo tree; boldo) and belongs to the family Monimiaceae. It exhibits a wide range of pharmacological effects such as antioxidant, anticancer, hepatoprotective, neuroprotective, and anti-diabetic properties. There is a dearth of information regarding its pharmacokinetics and toxicity in addition to its potential pharmacological activity. Boldine belongs to the aporphine alkaloid class and possesses lipophilic properties which enable its efficient absorption and distribution throughout the body, including the central nervous system. It exhibits potent free radical scavenging activity, thereby reducing oxidative stress and preventing neuronal damage. Through a variety of neuroprotective mechanisms, including suppression of AChE and BuChE activity, blocking of connexin-43 hemichannels, pannexin 1 channel, reduction of NF-κβ mediated interleukin release, and glutamate excitotoxicity which successfully reduces neuronal damage. These results point to its probable application in reducing neuroinflammation and oxidative stress in epilepsy, Alzheimer's disease (AD), and Parkinson's disease (PD). Moreover, its effects on serotonergic, dopaminergic, opioid, and cholinergic receptors were further investigated in order to determine its applicability for neurobehavioral dysfunctions. The article investigates the pharmacokinetics of boldine and reveals that it has a low oral bioavailability and a short half-life, requiring regular dosage to maintain therapeutic levels. The review studies boldine's potential therapeutic uses and mode of action while summarizing its neuroprotective benefits.  Given the favorable results for boldine as a potential neurotherapeutic drug in laboratory animals, more research is required. However, in order to optimise its therapeutic potential, it must be more bioavailable with fewer detrimental side effects.

Detection of Alzheimer's Disease Using Logistic Regression and Clock Drawing Errors

Alzheimer's disease is an incurable disorder that accounts for up to 70% of all dementia cases. While the prevalence of Alzheimer's disease and other types of dementia has increased by more than 160% in the last 30 years, the rates of undetected cases remain critically high. The present work aims to address the underdetection of Alzheimer's disease by proposing four logistic regression models that can be used as a foundation for community-based screening tools that do not require the participation of medical professionals. Our models make use of individual clock drawing errors as well as complementary patient data that is highly available and easily collectible. All models were controlled for age, education, and gender. The discriminative ability of the models was evaluated by area under the receiver operating characteristic curve (AUC), the Hosmer-Lemeshow test, and calibration plots were used to assess calibration. Finally, decision curve analysis was used to quantify clinical utility. We found that among 10 possible CDT errors, only 3 were informative for the detection of Alzheimer's disease. Our base regression model, containing only control variables and clock drawing errors, produced an AUC of 0.825. The other three models were built as extensions of the base model with the step-wise addition of three groups of complementary data, namely cognitive features (semantic fluency score), genetic predisposition (family history of dementia), and cardio-vascular features (BMI, blood pressure). The addition of verbal fluency scores significantly improved the AUC compared to the base model (0.91 AUC). However, further additions did not make a notable difference in discriminatory power. All models showed good calibration. In terms of clinical utility, the derived models scored similarly and greatly outperformed the base model. Our results suggest that the combination of clock symmetry and clock time errors plus verbal fluency scores may be a suitable candidate for developing accessible screening tools for Alzheimer's disease. However, future work should validate our findings in larger and more diverse datasets.

Clock Drawing Test: Types of Errors and Accuracy in Early Cognitive Screening

BACKGROUND

Clock Drawing Test (CDT) is a commonly used screening tool for cognitive disorders, known for its ease of administration and scoring. Despite frequent use by clinicians, CDT is criticized for its poor predictive value in mild cases of impairment.

OBJECTIVE

To evaluate CDT as a screening tool for early stage of cognitive impairment in biomarker-verified Alzheimer's disease (AD) and depressive disorder (DD).

METHODS

We analyzed CDT of 172 patients with verified AD, 70 patients with DD, in whom neurodegenerative disorder was excluded using cerebrospinal fluid biomarkers, and 58 healthy older adults. CDT was scored using the semi-quantitative (Shulman) and itemized criteria (adapted from Mendez).

RESULTS

Logistic regression showed that for both DD and AD patients with high Mini-Mental State Examination (MMSE) scores (27 and above) the significant predicting variable is uneven number spacing. As MMSE deteriorates (24-26 points), an additional error of setting clock hands is predictive of the disease. In the low MMSE condition, CDT showed an acceptable discrimination for AD (AUC itemized 0.740, Shulman 0.741) and DD (AUC itemized 0.827, Shulman 0.739) using both scoring methods. In the high MMSE condition, discrimination rates were acceptable using itemized scoring but poor using Shulman scoring for both AD (AUC itemized 0.707, Shulman 0.677) and DD (AUC itemized 0.755, Shulman 0.667) groups.

CONCLUSION

Ideally, modern diagnostic process should take place before the cognitive performance drops beneath the healthy range. This makes CDT of little use when screening patients with very mild cognitive deficits.

The clinical profile of cerebral small vessel disease: Toward an evidence-based identification of cognitive markers

There is no consensus on which test is more suited to outline the cognitive deficits of cerebral small vessel disease (cSVD) patients. We explored the ability of eight cognitive tests, selected in a previous systematic review as the most commonly used in this population, to differentiate among cSVD patients, controls, and other dementing conditions performing a meta-analysis of 86 studies. We found that cSVD patients performed worse than healthy controls in all tests while data on the comparison to neurodegenerative diseases were limited. We outlined a lack of data on these tests' accuracy on the diagnosis. Cognitive tests measuring processing speed were those mostly associated with neuroimaging cSVD markers. There is currently incomplete evidence that a single test could differentiate cSVD patients with cognitive decline from other dementing diseases. We make preliminary proposals on possible strategies to gain information about the clinical definition of cSVD that currently remains a neuroimaging-based one.

Limits on using the clock drawing test as a measure to evaluate patients with neurological disorders

BACKGROUND

The Clock Drawing Test (CDT) is used as a quick-to-conduct test for the diagnosis of dementia and a screening tool for cognitive impairments in neurological disorders. However, the association between the pattern of CDT impairments and the location of brain lesions has been controversial. We examined whether there is an association between the CDT scores and the location of brain lesions using the two available scoring systems.

METHOD

One hundred five patients with brain lesions identified by CT scanning were recruited for this study. The Montreal Cognitive Assessment (MoCA) battery including the CDT were administered to all partcipants. To score the CDT, we used a qualitative scoring system devised by Rouleau et al. (1992). For the quantitative scoring system, we adapted the algorithm method used by Mendes-Santos et al. (2015) based on an earlier study by Sunderland et al. (1989). For analyses, a machine learning algorithm was used.

RESULTS

Remarkably, 30% of the patients were not detected by the CDT. Quantitative and qualitative errors were categorized into different clusters. The classification algorithm did not differentiate the patients with traumatic brain injury 'TBI' from non-TBI, or the laterality of the lesion. In addition, the classification accuracy for identifying patients with specific lobe lesions was low, except for the parietal lobe with an accuracy of 63%.

CONCLUSION

The CDT is not an accurate tool for detecting focal brain lesions. While the CDT still is beneficial for use with patients suspected of having a neurodegenerative disorder, it should be cautiously used with patients with focal neurological disorders.

Time setting errors in the Clock Drawing Test are associated with both semantic and executive deficits

The common requirement to set the time to "10 past 11" on the Clock Drawing Test is intended to elicit a stimulus bound response (SBR), in which the responder is "pulled" to the salient stimulus "10," resulting in hands set at "10 before 11." SBRs are considered markers of executive dysfunction, although this assumption has not yet been validated. We compared SBR and other time-setting errors on inhibitory control tests, hypothesizing that they represent related constructs. The role of semantic dysfunction in the formation of those errors was also investigated. We examined baseline test performance of participants with Mild Cognitive Impairment or a history of depression, and control participants, enrolled in a dementia prevention study. Among 258 participants, we identified clocks with SBRs (n = 16), other time errors (n = 22), or no errors at all (n = 42). Performance between the groups with SBRs and other time-setting errors did not differ on any of the executive tests, and both error groups performed significantly worse than the No Error group on the semantic tests. Control for covariates further supported semantic and executive components in time-setting errors. Both semantic and inhibitory control deficits may underlie time representation errors in general.

Evaluating a novel behavioral paradigm for visual hallucinations in Dementia with Lewy bodies

The aim of this study was to evaluate the utility of the Bistable Percept Paradigm (BPP), a computerised behavioural task that has previously been utilised for the assessment of visual hallucinations in Parkinson's Disease, in a Dementia with Lewy bodies (DLB) cohort. Dementia with Lewy bodies patients demonstrated poorer performance than healthy controls (HC) on the BPP with significantly more misperceptions and a greater failure to detect bistable percepts correctly compared to HC. Further, the number of misperceptions was also correlated with the severity of hallucinations. The findings from this study demonstrate that the BPP is a viable tool to measure misperceptions in DLB patients.

Network topology and machine learning analyses reveal microstructural white matter changes underlying Chinese medicine Dengzhan Shengmai treatment on patients with vascular cognitive impairment

With the increasing incidence of cerebrovascular diseases and dementia, considerable efforts have been made to develop effective treatments on vascular cognitive impairment (VCI), among which accumulating practice-based evidence has shown great potential of the traditional Chinese medicine (TCM). Current randomized double-blind controlled trial has been designed to evaluate the 6-month treatment effects of Dengzhan Shengmai (DZSM) capsules, one TCM herbal preparations on VCI, and to explore the underlying neural mechanisms with graph theory-based analysis and machine learning method based on diffusion tensor imaging (DTI) data. A total of 82 VCI patients were recruited and randomly assigned to drug (45 with DZSM) and placebo (37 with placebo) groups, and neuropsychological and neuroimaging data were acquired at baseline and after 6-month treatment. After treatment, compared to the placebo group, the drug groups showed significantly improved performance in Alzheimer's Disease Assessment Scale-Cognitive subscale (ADAS-cog) score (p < 0.001) and the other cognitive domains. And with the reconstruction of white matter structural network, there were more streamlines connecting the left thalamus and right hippocampus in the drug groups (p < 0.001 uncorrected), with decreasing nodal efficiency of the right olfactory associated with slower decline in the general cognition (r = -0.364, p = 0.048). Moreover, support vector machine classification analyses revealed significant white matter network alterations after treatment in the drug groups (accuracy of baseline vs. 6-month later, 68.18 %). Taking together, the present study showed significant efficacy of DZSM treatment on VCI, which might result from white matter microstructure alterations and the topological changes in brain structural network.

Quantitative and Qualitative Analyses of the Clock Drawing Test in Fall and Non-Fall Patients with Alzheimer's Disease

Aim

The clock drawing test (CDT) is widely used as a visual spatial ability test and screening test for dementia patients. The appearance frequency of qualitative errors obtained through the qualitative analysis of CDT may be related to the participant's falls. The aim of this study was to clarify the difference in the number of people who presented with qualitative errors in the CDT between a fall and non-fall group of patients with Alzheimer's disease (AD).

Methods

The CDT was implemented for 47 patients with AD. A quantitative analysis was conducted, and a qualitative analysis was performed for errors. The patients were divided into two groups based on their history of falls over the past year. The results of the CDT quantitative analysis were tested using the Mann-Whitney U test, and Fisher's exact test was employed to determine the difference in the number of people who presented with error types between the two groups (fall group, non-fall group) in the CDT qualitative analysis.

Results

In the quantitative analysis, a significant difference was found for the total scores, with the total CDT score of the fall group (n = 22) significantly lower than that of the non-fall group (n = 25) (p = 0.006, effect size: φ = 0.40). In the qualitative analysis, a significantly higher number of patients in the fall group than in the non-fall group presented with a conceptual deficit (p =0.001, φ = 0.51). No differences were found in the number of patients in the two groups who presented with the other five error types.

Conclusions

These results showed that a lower score in the CDT quantitative analysis might suggest an increased risk of falls. It was also clarified that a larger number of patients in the fall group than in the non-fall group presented with a conceptual deficit of the qualitative error types in the CDT. Therefore, these results suggest that the appearance of a conceptual deficit may be an index for the selection of patients with AD prone to falling when implementing fall prevention measures.

Cognitive screening instruments to identify vascular cognitive impairment: A systematic review

INTRODUCTION

Vascular cognitive impairment (VCI) is common and important to detect as controlling risk factors, particularly hypertension, may slow onset and progression. There is no consensus as to which cognitive screening instrument (CSI) is most suitable for VCI. We systematically reviewed the psychometric properties of brief CSIs for vascular mild cognitive impairment (VMCI) and vascular dementia (VaD).

METHODS

Literature searches were performed using scholarly databases from inception until 31 May 2018. Studies were eligible if participants were aged 18 or older, interviewed face-to-face, and standard diagnostic criteria for VCI were applied, excluding those specifically identifying post-stroke dementia. Risk of bias was assessed using the Quality in Prognosis Studies (QUIPS) tool.

RESULTS

Fifteen studies were identified including eight types of CSIs (27 subtests/variants) and 4575 participants (1015 with VCI), mean age range: 51.6 to 75.5 years. Most studies compared more than one instrument. Five papers examined clock-drawing; four, the Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE); and three used the Brief Memory and Executive Test (BMET). The MoCA (AUC > 0.90) and MMSE (AUC: 0.86-0.99) had excellent accuracy in differentiating VaD from controls; the MoCA had good internal consistency (Cronbach's α: .83-.88). The MoCA (AUC: 0.87-0.93) and BMET (AUC: 0.94) had the greatest accuracy in separating VMCI from controls. Most studies had low to moderate risk of bias in all domains of the QUIPS. Data were heterogeneous, precluding a meta-analysis.

CONCLUSIONS

Although few studies were available and further research is required, data suggests that the MoCA is accurate and reliable for differentiating VaD and VMCI from controls.

Qualitative analysis and identification of pattern of errors in Clock Drawing Tests of community-dwelling older adults

The Clock Drawing Test (CDT) is a frequently employed screening tool with different scoring systems. Quantitative and semi-quantitative scoring systems, such as Sunderland’s et al. (1989), do not discriminate different error patterns. Thus, the same score can represent a number of different neuropsychological profiles. Therefore, the use of a scoring method that emphasizes qualitative aspects to determine specific error patterns is fundamental.

The test of time: a history of clock drawing

OBJECTIVE

The clock drawing test (CDT) has become one of the most widely used cognitive screening instruments in clinical and research settings. Its effectiveness, acceptability, and quick and easy administration have made it a staple for cognitive screening in dementia and a wide range of brain disorders. Despite a spike in popularity since the 1990s, its origins are relatively unknown. The goal of this review is to chronicle its saga and chart its usage over time.

METHODS

PsycInfo, Medline, and PubMed literature searches were performed from earliest record to June 2016, in addition to manual cross-referencing of bibliographies, with a focus before 1990. Summary of relevant articles and books up until 1989 is included, as well as clinical applications and surveys that track CDT usage over time.

RESULTS

While MacDonald Critchley's well-known textbook from 1953, The Parietal Lobes, is often cited as the first mention of the CDT, its recorded use actually stretches back more than a century to 1915. A review of the literature shows that the CDT began as a test for aphasia-related disorders and constructional apraxia until its entry into contemporary cognitive screening in the 1980s when it primarily became a cognitive screen. Its usage took off in 1989 with over 2000 publications since.

CONCLUSIONS

Despite a fairly obscure existence for decades, the CDT has emerged as an effective and ideal cognitive screening instrument for a wide range of conditions. Its use continues to increase, and it has been incorporated into several widely used cognitive screening batteries. Copyright © 2017 John Wiley & Sons, Ltd.

Can visuospatial measures improve the diagnosis of Alzheimer's disease?

Introduction

Overlapping and evolving symptoms lead to ambiguity in the diagnosis of dementia. Visuospatial function relies on parietal lobe function, which may be affected in the early stages of Alzheimer's disease (AD). This review evaluates visuospatial dysfunction in patients with AD, frontotemporal dementia, dementia with Lewy bodies, and vascular dementia to determine the diagnostic and prognostic potential of visuospatial tasks in AD.

Methods

A systematic search of studies (1960–2016) investigating visuospatial dysfunction in dementia was conducted.

Results

Tests measuring construction, specifically Block Design and Clock Drawing Test, and visual memory, specifically Rey-Osterrieth Complex Figure recall and topographical tasks, show the greatest diagnostic potential in dementia. The Benton visual retention, Doors and People, and topographical memory tests show potential as prognostic markers.

Discussion

Tests of visuospatial function demonstrate significant diagnostic and prognostic potential in dementia. Further studies with larger samples of pathologically confirmed cases are required to verify clinical utility.

•

Memory deficits have been demonstrated in Alzheimer's and non-Alzheimer's dementias.

•

Parietal lobes are uniquely affected in the early stages of Alzheimer's disease.

•

Visuospatial tasks demonstrate significant diagnostic and prognostic potential.

•

Computerized test protocols have been developed to test aspects of visuospatial function and memory.

•

Novel topographical memory tasks demonstrated the greatest prognostic potential.

Scoring systems for the Clock Drawing Test: A historical review

The Clock Drawing Test (CDT) is a simple neuropsychological screening instrument that is well accepted by patients and has solid psychometric properties. Several different CDT scoring methods have been developed, but no consensus has been reached regarding which scoring method is the most accurate. This article reviews the literature on these scoring systems and the changes they have undergone over the years. Historically, different types of scoring systems emerged. Initially, the focus was on screening for dementia, and the methods were both quantitative and semi-quantitative. Later, the need for an early diagnosis called for a scoring system that can detect subtle errors, especially those related to executive function. Therefore, qualitative analyses began to be used for both differential and early diagnoses of dementia. A widely used qualitative method was proposed by Rouleau et al. (1992). Tracing the historical path of these scoring methods is important for developing additional scoring systems and furthering dementia prevention research.

Drawing Disorders in Alzheimer's Disease and Other Forms of Dementia

Drawing is a multicomponential process that can be impaired by many kinds of brain lesions. Drawing disorders are very common in Alzheimer's disease and other forms of dementia, and can provide clinical information for the distinction of the different dementing diseases. In our review we started from an overview of the neural and cognitive bases of drawing, and from a recollection of the drawing tasks more frequently used for assessing individuals with dementia. Then, we analyzed drawing disorders in dementia, paying special attention to those observed in Alzheimer's disease, from the prodromal stages of the amnesic mild cognitive impairment to the stages of full-blown dementia, both in the sporadic forms with late onset in the entorhino-hippocampal structures and in those with early onset in the posterior neocortical structures. We reviewed the drawing features that could differentiate Alzheimer's disease from vascular dementia and from the most frequent forms of degenerative dementia, namely frontotemporal dementia and Lewy body disease. Finally, we examined some peculiar aspects of drawing disorders in dementia, such as perseverations, rotations, and closing-in. We argue that a careful analysis of drawing errors helps to differentiate the different forms of dementia more than overall accuracy in drawing.

Can clock drawing differentiate Alzheimer's disease from other dementias?

BACKGROUND

Studies have shown the clock-drawing test (CDT) to be a useful screening test that differentiates between normal, elderly populations, and those diagnosed with dementia. However, the results of studies which have looked at the utility of the CDT to help differentiate Alzheimer's disease (AD) from other dementias have been conflicting. The purpose of this study was to explore the utility of the CDT in discriminating between patients with AD and other types of dementia.

METHODS

A review was conducted using MEDLINE, PsycINFO, and Embase. Search terms included clock drawing or CLOX and dementia or Parkinson's Disease or AD or dementia with Lewy bodies (DLB) or vascular dementia (VaD).

RESULTS

Twenty studies were included. In most of the studies, no significant differences were found in quantitative CDT scores between AD and VaD, DLB, and Parkinson's disease dementia (PDD) patients. However, frontotemporal dementia (FTD) patients consistently scored higher on the CDT than AD patients. Qualitative analyses of errors differentiated AD from other types of dementia.

CONCLUSIONS

Overall, the CDT score may be useful in distinguishing between AD and FTD patients, but shows limited value in differentiating between AD and VaD, DLB, and PDD. Qualitative analysis of the type of CDT errors may be a useful adjunct in the differential diagnosis of the types of dementias.

[Comparative study of eating behavior in elderly patients with Alzheimer's disease and vascular dementia: a first report. - Comparison of disturbed eating behavior - ]

AIM

In elderly patients with dementia, it is known that a loss of independence in eating can cause malnutrition, dehydration, a decrease in food consumption and the immune function and further worsening of the cognitive function, with an increased risk of pneumonia and a shortened life expectancy. The purpose of this study was to investigate the occurrence of a disturbed eating behavior in elderly patients with Alzheimer's disease (AD) and vascular dementia (VaD), who together comprise the majority of elderly patients with dementia.

METHODS

A total of 233 patients (150 AD patients and 83 VaD patients) who were residents of institutions or group homes were enrolled. The patients underwent an assessment of eating behavior, a cognitive assessment, a neurological examination and measurement of the vital signs. Additionally, statistical analyses were performed to compare eating behavior between the patients with AD and those with VaD at varying severity of dementia.

RESULTS

A disturbed eating behavior was observed significantly more frequently as the severity of dementia increased. The prevalence of difficulty in rinsing/gargling and dysphagia increased with the severity of dementia. There were differences in the frequency of disturbed eating behavior between the AD and VaD patients. Among the patients with mild dementia, the VaD patients exhibited a higher incidence of a disturbed eating behavior than the AD patients. On the other hand, some behaviors prominent in the patients with severe dementia were related to various types of cognitive impairment in the AD patients, namely difficulty in beginning a meal, difficulty in maintaining attention while eating and difficulty in performing the specific motor skills necessary to open food packages. Marked individual differences were observed in the mild VaD patients, with a high frequency of disturbed eating behavior and dysphagia related to symptoms of neurological deficits. No correlations were found with the severity of dementia.

CONCLUSIONS

Both AD and VaD are types of dementia; however, the frequency of a disturbed eating behavior differs greatly between these populations. It is necessary to focus on differences in these parameters and also the causes of dementia in order to develop effective care techniques for patients with dementia.

Qualitative analysis of the Clock Drawing Test by educational level and cognitive profile

The use of a qualitative scale for the Clock Drawing Test (CDT) may add information about the pattern of errors committed.

OBJECTIVE

To translate and adapt the Modified Qualitative Error Analysis of Rouleau into Brazilian Portuguese and to examine the pattern of errors according to educational level and cognitive profile.

METHOD

180 adults (47-82 years) completed the CDT. Participants were stratified into age and educational levels and separated between those with and without changes in cognitive screening tests (Mini-Mental State Examination, Verbal Fluency).

RESULTS

No significant differences were found in CDT scores among age groups. Among participants without cognitive impairment, those with lower education often presented graphic difficulties, conceptual deficits and spatial deficits. Participants with cognitive deficits, demonstrated more frequently conceptual and spatial errors.

CONCLUSION

The qualitative analysis of the CDT may contribute to the identification of cognitive changes. Education level has to be taken into consideration during the analysis.

The six-item Clock Drawing Test - reliability and validity in mild Alzheimer's disease

This study presents a reliable, short and practical version of the Clock Drawing Test (CDT) for clinical use and examines its diagnostic accuracy in mild Alzheimer's disease versus elderly nonpatients. Clock drawings from 231 participants were scored independently by four clinical neuropsychologists blind to diagnostic classification. The interrater agreement of individual scoring criteria was analyzed and items with poor or moderate reliability were excluded. The classification accuracy of the resulting scoring system - the six-item CDT - was examined. We explored the effect of further reducing the number of scoring items on classification accuracy and estimated classification accuracy associated with performances deviating from the optimal cutoff score. At a cutoff of 5/6, the six-item CDT had a sensitivity (SN) of 0.65 and a specificity of 0.80. Stepwise removal of up to three items reduced SN slightly. Classification accuracy associated with a score of four or less out of six was very high.

[Quantitative and qualitative analyses for characteristics of the clock drawing in Alzheimer's disease]

We analyzed the results of the clock drawing test (CDT) in patients with Alzheimer's disease (AD) by quantitative and qualitative methods to evaluate its significance for cognitive function screening. We administered the CDT and mini-mental state examination (MMSE) to a total of 156 AD patients, and CDT performance was scored quantitatively in accordance with the method by Freedman, while the CDT error types were qualitatively classified by Rouleau's method. We divided AD patients into three groups by their MMSE total score (A: 23 ≤, B: 18~22, C: ≤ 17). The mean total scores of CDT and MMSE in AD were 11.5 ± 3.4 and 19.8 ± 4.7, respectively, and the total CDT scores showed significant positive correlation with the total MMSE scores (r = 0.450). Fewer than 80% of subjects drew the clock correctly for 8 out of 15 sub-items, and fewer were able to correctly draw clock hands than could correctly draw numbers, contour or a center. In analysis of CDT qualitative error types, the most common error types were spatial and/or planning deficit (SPD) (28.2%), and conceptual deficit (CD) (23.7%), which suggested visuospatial impairments and semantic impairments play essential roles in AD patients' poor clock drawings. The frequency of CD and SPD error types significantly increased as severity of cognitive function worsened (p < 0.001, p < 0.05, respectively), and those of stimulus-bound response and perseveration had tendency to increase as severity of cognitive function. The present study suggests that CDT is a useful screening method not only for the impairment of cognitive function and the severity of cognitive dysfunction, but also for identification of specific cognitive function impairments in AD patients.

Neural correlates of the components of the clock drawing test

BACKGROUND

The aim of this study was to identify the neural correlates of each component of the clock drawing test (CDT) in drug-naïve patients with Alzheimer's disease (AD) using single photon emission computed tomography.

METHODS

The participants were 95 drug-naïve patients with AD. The Rouleau CDT was used to score the clock drawings. The score for the Rouleau CDT (R total) is separated into three components: the scores for the clock face (R1), the numbers (R2), and the hands (R3). A multiple regression analysis was performed to examine the relationship of each score (i.e. R total, R1, R2, and R3) with regional cerebral blood flow (rCBF). Age, gender, and education were included as covariates. The statistical threshold was set to a family-wise error (FWE)-corrected p value of 0.05 at the voxel level.

RESULTS

The R total score was positively correlated with rCBF in the bilateral parietal and posterior temporal lobes and the right middle frontal gyrus. R1 was not significantly positively correlated with rCBF, R2 was significantly positively correlated with rCBF in the right posterior temporal lobe and the left posterior middle temporal lobe, and R3 was significantly positively correlated with rCBF in the bilateral parietal lobes, the right posterior temporal lobe, the right middle frontal gyrus, and the right occipital lobe.

CONCLUSIONS

Various brain regions were associated with each component of the CDT. These results suggest that an assessment of these components is useful for the detection of localization of brain damage.

The Mini-Cog versus the Mini-Mental State Examination and the Clock Drawing Test in daily clinical practice: screening value in a German Memory Clinic

BACKGROUND

The aim of this study was to compare the screening value of the Mini-Cog, Clock Drawing Test (CDT), Mini-Mental State Examination (MMSE) and the algorithm MMSE and/or CDT to separate elderly people with dementia from healthy depending on test time, type and severity of dementia, and demographic variables in a German Memory Clinic.

METHODS

Data from a heterogeneous patient sample and healthy participants (n = 502) were retrospectively analyzed. Of the 438 patients with dementia, 49.1% of the dementia diagnoses were Alzheimer's dementia and 50.9% were non-Alzheimer's dementia. Sixty-four participants were classified as cognitively unimpaired. The CDT and an extraction of the 3-item recall of the MMSE were used to constitute the Mini-Cog algorithm.

RESULTS

Overall, the Mini-Cog showed significantly higher discriminatory power (86.8%) than the MMSE (72.6% at a cut-off ≤ 24 and 79.2% at ≤ 25, respectively) and CDT (78.1%) (each p < 0.01) and did not perform worse than the algorithm MMSE and/or CDT (each p > 0.05). The specificity of the Mini-Cog (100.0%) was similar to that of the MMSE (100.0% for both cut-offs) and CDT (96.9%) (p = 0.154). For all age and educational groups the Mini-Cog outmatched the CDT and MMSE, and was less affected by education than MMSE and less susceptible for the dementia stage than the CDT.

CONCLUSION

The Mini-Cog proved to have superior discriminatory power than either CDT or MMSE and is demonstrated to be a valid "short" screening instrument taking 3 to 4 minutes to administer in the geriatric setting.

Effects of education, literacy, and dementia on the Clock Drawing Test performance

The Clock Drawing Test (CDT) has been recognized as an effective tool for dementia detection. This study investigated the clock drawing performance of 240 non-demented elderly Korean people with a wide-range of educational levels and 28 patients with mild dementia of the Alzheimer's type (DAT). We examined the effects of demographic factors, including education, and established norms for the elderly population. We found that the educational attainment and literacy status of older people influenced performance on the CDT significantly (p < .001). Furthermore, qualitative error analysis revealed that normal participants with low educational background committed errors similar to errors of the DAT patients. The DAT patients performed significantly worse than the non-demented participants in the CDT Total score (p < .001). However, the CDT has better criterion validity in participants with more than 6 years of education. In conclusion, the CDT performance in older people who are either illiterate or with 6 or less years of education should be interpreted with caution. Conceptual errors in the CDT can be the result of not only dementia but also lack of education.

The Four-Point Scoring System for the Clock Drawing Test Does Not Differentiate between Alzheimer's Disease and Vascular Dementia

The purpose of this study was to explore the sensitivity and specificity of the Clock Drawing Test by using a widely employed four-point scoring system to discriminate between patients with Alzheimer's disease or vascular dementia. Receiver operating characteristic analysis indicated that the Clock Drawing Test was able to distinguish between normal elders and those with a dementia diagnosis. The cutoff score for differentiating patients with Alzheimer's disease from normal participants was = 3. The cutoff score for differentiating those with vascular disease from normal participants was = 3. Overall, the four-point scoring system demonstrated good sensitivity and specificity for identifying cognitive dysfunction associated with dementia; however, the current findings do not support the utility of the four-point scoring system in discriminating Alzheimer's disease and vascular dementia.

Clock test deficits are associated with semantic memory impairment in Alzheimer disease

Based on previous findings, we hypothesized that Clock Test deficits in patients with Alzheimer disease (AD) are associated primarily with the impairment of semantic memory regarding the appearance and functionality of a clock. To scrutinize this hypothesis, we developed a Clock Questionnaire that examined the semantic knowledge of the concept of a ''Clock'' and correlated scores from the questionnaire with performance in Clock Drawing, Clock Setting, and Clock Reading by healthy control participants and patients with mild cognitive impairment, early AD, and progressed AD. The Rey-Osterrieth-Complex-Figure is known to measure both visuospatial abilities and executive functions, and was chosen as a control variable. We found that deteriorated semantic memory best predicted Clock Test performance. In progressed AD, degraded knowledge regarding the appearance of a clock can explain the reduced ability to draw a clock face, while in early AD, impaired access to semantic knowledge about the minute hand might explain observed difficulties in drawing, setting, and reading the minute hand.

The minute hand phenomenon in the Clock Test of patients with early Alzheimer disease

Common scoring systems for the Clock Test do not sufficiently emphasize the correct time representation by the clock hands. We compared Clock Drawing, Clock Setting, and Clock Reading in healthy control persons, patients with mild cognitive impairment, early Alzheimer disease and progressed Alzheimer disease particularly analyzing clock time representation. We found that healthy control persons and participants with mild cognitive impairment did not show any impairment in Clock Test performance. Patients with early Alzheimer disease could be discriminated from healthy control persons and participants with mild cognitive impairment solely by misplacement of the minute hand in Clock Drawing and Clock Setting. The progressed Alzheimer disease group showed significantly more impairments in all Clock Test variants. It is assumed that early stage Alzheimer disease patient deficits in Clock Tests are mainly determined by a reduced access to semantic memory about the appearance and functionality of a clock.

Does the Clock Drawing Test have focal neuroanatomical correlates?

The Clock Drawing Test (CDT) is widely used in clinical neuropsychological practice. The CDT has been used traditionally as a "parietal lobe" test (e.g., Kaplan, 1988), but most empirical work has focused on its sensitivity and specificity for detecting and differentiating subtypes of dementia. There are surprisingly few studies of its neuroanatomical correlates. The authors investigated the neuroanatomical correlates of the CDT, using 133 patients whose lesions provided effective coverage of most of both hemispheric convexities and underlying white matter. On the CDT, 30 subjects were impaired and 87 were unimpaired (16 were "borderline"). Impairments on the CDT were associated with damage to right parietal cortices (supramarginal gyrus) and left inferior frontal-parietal opercular cortices. Visuospatial errors were predominant in patients with right hemisphere damage, whereas time setting errors were predominant in patients with left hemisphere lesions. These findings provide new empirical evidence regarding the neuroanatomical correlates of the CDT, and together with previous work, support the use of this quick and easily administered test not only as a screening measure but also as a good index of focal brain dysfunction.

Clock drawing performance and brain morphology in mild cognitive impairment and Alzheimer's disease

The Clock Drawing Test (CDT) is a widely used instrument in the neuropsychological assessment of Alzheimer's disease (AD). As CDT performance necessitates several cognitive functions (e.g., visuospatial and constructional abilities, executive functioning), an interaction of multiple brain regions is likely. Fifty-one subjects with mild cognitive impairment, 23 with AD and 15 healthy controls underwent high-resolution magnetic resonance imaging. Optimized voxel-based morphometry (VBM) was performed to investigate the putative association between CDT performance and gray matter (GM) density throughout the entire brain. In the first step of analysis (p<.001, uncorrected), VBM revealed a reduced GM density in numerous cortical (temporal lobe, frontal lobe, parietal lobe, cerebellum) and subcortical (thalamus, basal ganglia) brain regions to be associated with poorer CDT performance. When corrected for multiple comparisons (p<.01), the associations remained significant predominantly in the left temporal and--less pronounced--the right temporal lobe. VBM demonstrated CDT performance to depend on the integrity of widely distributed cortical and subcortical areas in both brain hemispheres with accentuation in the left-sided temporal lobe region.

Quantitative and qualitative analyses of clock drawing in frontotemporal dementia and Alzheimer's disease

The clock drawing test (CDT) is a widely used cognitive screening test. It is useful in identifying focal lesions and cognitive deficits in dementia groups. Lately, several studies attempted its use to differentiate between dementia subtypes. Although many studies have examined the CDT in dementia populations, research into the use of clock drawing in frontotemporal dementia (FTD) is limited. We examined quantitative (global) and qualitative (specific error type) differences on the CDT between FTD (n = 36) and Alzheimer's disease (AD; n = 25) patients and controls without dementia (n = 25). Results showed significantly lower overall scores in the dementia groups compared to the control group, whereas FTD patients scored significantly higher than the AD group. On qualitative analysis, the FTD group had fewer stimulus bound responses, conceptual deficits, and spatial or planning errors compared to the AD group. In conclusion, both global and error analysis of the CDT helped discriminate the FTD group from controls and AD patients.

Performance of three clock scoring systems across different ranges of dementia severity

The ability of three different Clock Drawing Test (CDT) scoring systems to detect Dementia of the Alzheimer Type (DAT) was investigated. As part of a neuropsychological battery, fifty DAT Type patients and fifty matched controls drew a clock. Each drawing was scored by three independent raters according to three different scoring systems: the 3-Factor system, the Template system, and the Abbreviated system. The CDT scoring systems were able to detect Dementia of the Alzheimer Type when the disease was moderate to severe, but lacked sensitivity in milder dementia. Animal Fluency was a better single predictor of dementia. Clinicians are advised to interpret the results of the Clock Drawing Test cautiously in an outpatient setting, where milder forms of dementia and low base rates are likely.

The clock drawing test as a measure of executive dysfunction in elderly depressed patients

The aims of this research were to determine whether performance on the Clock Drawing Test (CDT) could accurately distinguish between older patients with depression and older patients with depression and previously undocumented executive dysfunction and to determine if there was a correlation between CDT and depression severity. The authors studied 52 patients consecutively admitted to a geriatric psychiatry inpatient unit of a university hospital who met DSM-IV criteria for major depression or depression not otherwise specified but had no concurrent diagnosis of dementia. All the subjects completed the Mini-Mental State Examination (MMSE), Mattis Dementia Rating Scale (DRS), and the CDT, as well as the Geriatric Depression Scale (GDS). The patients were divided into 2 subgroups based on the DRS score: <129 (cognitive impairment) versus = 129. Results indicated that the depressed patients with a score of DRS <129 had significantly lower CDT scores than did patients with DRS = 129 and normal comparison subjects (P< .01). The results support the hypothesis that CDT score is lower in elderly depressed patients with executive dysfunction versus nondepressed seniors as well as depressed patients without executive dysfunction.

Clock Drawing Test-Modified and Integrated Approach (CDT-MIA): description and preliminary examination of its validity and reliability in dementia patients referred to a specialized psychogeriatric setting

The authors developed a scoring system for clock drawing, based on modification and integration of 3 established scoring methods. The Clock Drawing Test-Modified and Integrated Approach (CDT-MIA) is a 4-step, 20-item instrument, with a maximum score of 33, which emphasizes differential scoring of contour, numbers, hands, and center. It was administered to 139 patients (93 with and 46 without dementia). Dementia patients revealed significantly more impairment on the CDT-MIA total score and hours and hands subscores. Correlations between CDT-MIA and 2 CDTs were high. With receiver operating characteristics (ROC) curves, the area constructed under CDT-MIA curve was large. The best trade-off between sensitivity and specificity for CDT-MIA was the cut-point 23 (91% and 80%, respectively). The internal consistency of CDT-MIA was high, and there was a high degree of interrater reliability. Thus, CDT-MIA was found to be a valid and reliable evaluation instrument for dementia patients in a specialized setting.

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.