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

Using Deep Learning Neural Networks to Improve Dementia Detection: Automating Coding of the Clock-Drawing Test

Alzheimer's disease and related dementias (ADRD) is a growing public health concern. The clock-drawing test (CDT), where subjects draw a clock, typically with hands showing 11:10, has been widely used for ADRD-screening. A limitation of including CDT in large-scale studies is that the CDT requires manual coding, which could result in biases if coders interpret and implement coding rules differently. This study created and evaluated an intelligent CDT Clock Scoring system built with Deep Learning Neural Networks (DLNN) to automatically code CDT images. We used a large, publicly available repository of CDT images from the 2011-2019 National Health and Aging Trends Study (NHATS) and compared three advanced DLNN methods - ResNet101, EfficientNet and Vision Transformers (ViT) in coding CDT into binary and ordinal (0 to 5) scores. We extended beyond the traditional nominal classification approach (which does not recognize order) by introducing structured ordering into the coding system and compared DLNN-coded CDT images with manual coding. Results suggest that ViT outperforms ResNet101 and EfficientNet, as well as manual coding. The ordinal coding system has the ability to allow researchers to minimize either under- or over-estimation errors. Starting in 2022, our developed ViT-coding system has been used in NHATS' annual CDT-coding.

Assessment of visuospatial functions in post-Covid 19 patients: Beyond the traditional paradigm

Several studies indicate that some cognitive changes occur after COVID-19. Visuospatial alterations have been reported in 24-40 %. These alterations may be useful as early biomarkers of neurodegenerative disease. Thus, we can emphasize the importance of visuospatial processes in cognition through quantitative and qualitative analysis of performance on the Clock Test (CDT) and the Rey-Osterrieth Complex Figure (FCRO). Our objective was to describe the performance of post COVID 19 patients in visuospatial tests, with different degrees of respiratory impairment and to perform a qualitative analysis of the performance to check its relationship with alterations in attention and executive functions. This will allow highlighting the executive component of the performance of the CDT and ROCF and differentiate patients with possible cognitive impairment. 77 patients with SARS-CoV-2 infection were evaluated (3 months post-infection) with a complete neuropsychological battery and MRI. Overall, there is a significant difference between FCRO and CDT, with FCRO having only 9 % change and CDT having 51.9 % change. Regarding the correlations observed between groups (VM Inv, VM non I and non hospitalized) the highest correlations were observed between Boston with FCRO copy (r=0.497; p=0.001) and with FCRO memory (r=0.429; p=0.001). Comparing the performance between groups by severity, significant differences were observed only in the TMT A (13.706 p=0.001) and B (9.583 p=0.008) tests and in the phonological fluency letter A (13.445 p=0.001), we observed that the group of non-hospitalized patients had a better performance. Neuropsychological deficits often have a direct impact on daily life by affecting the ability to learn and adapt. Thus, a useful strategy for the neuropsychological characterization of post-COVID-19 patients is the qualitative analysis of visuospatial abilities in conjunction with executive functions that cannot be analyzed in isolation.

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.

About time: neurocognitive correlates of stimulus-bound and other time setting errors in the Clock Drawing Test

OBJECTIVE

Previous findings suggest that time setting errors (TSEs) in the Clock Drawing Test (CDT) may be related mainly to impairments in semantic and executive function. Recent attempts to dissociate the classic stimulus-bound error (setting the time to "10 to 11" instead of "10 past 11") from other TSEs, did not support hypotheses regarding this error being primarily executive in nature or different from other time setting errors in terms of neurocognitive correlates. This study aimed to further investigate the cognitive correlates of stimulus-bound errors and other TSEs, in order to trace possible underlying cognitive deficits.

METHODS

We examined cognitive test performance of participants with preliminary diagnoses associated with mild cognitive impairment. Among 490 participants, we identified clocks with stimulus-bound errors (n = 78), other TSEs (n = 41), other errors not related to time settings (n = 176), or errorless clocks (n = 195).

RESULTS

No differences were found on any dependent measure between the stimulus-bound and the other TSErs groups. Group comparisons suggested TSEs in general, to be associated with lower performance on various cognitive measures, especially on semantic and working memory measures. Regression analysis further highlighted semantic and verbal working memory difficulties as being the most prominent deficits associated with these errors.

CONCLUSION

TSEs in the CDT may indicate underlying deficits in semantic function and working memory. In addition, results support previous findings related to the diagnostic value of TSEs in detecting cognitive impairment.

Comparison of Behavior-Related Features in the MMSE Sentence in Behavioral Variant Frontotemporal Dementia and Alzheimer's Disease

Background: Despite the ubiquity of cognitive assessments using the MMSE, there has been little investigation of currently unscored features of the MMSE sentence item relevant to behavior and language in patients with behavioral variant Frontotemporal Dementia (bvFTD) and Alzheimer's disease (AD). Objective: To describe and compare the unscored content and grammar elements of the MMSE sentence item in patients with bvFTD and AD. Methods: Categorization of predefined content and grammar elements of the MMSE sentence was performed by two blinded raters in patients with bvFTD (n = 74) and AD (n = 84). Chi-square and ANCOVAs were conducted to identify differences between the diagnostic groups. A multinomial logistic regression analysis was conducted to determine whether these features aid in the prediction of diagnosis of bvFTD or AD. Results: A higher proportion of patients with bvFTD wrote sentences addressed to the examiner (22.7% vs. 4.7%, X 2 = 11.272, p = 0.001) and about interpersonal relationships (35.3% vs. 16.0%, X 2 = 10.139, p = 0.017) in comparison to those with AD. The number of words written was lower in patients with AD and was positively correlated with lower total MMSE scores in AD but not in bvFTD (AD: r = 0.370, p < 0.001; FTD: r = 0.209, p = 0.07). Assessment of the MMSE sentence content and grammar variables did not add to the prediction bvFTD or AD diagnosis beyond the variance explained by age and total MoCA score. Conclusions: Patients with bvFTD and AD showed differences in aspects of the content of the written MMSE sentence item, though these differences did not aid in the diagnosis prediction.

A systematic review and meta-analysis of the accuracy of the clock drawing test (CDT) in the identification of delirium in older hospitalised patients

Objective: Delirium is a common neurocognitive syndrome among hospitalised older adults. The clock drawing test (CDT) is a relatively simple bedside test of cognitive function. This systematic review and meta-analysis examine the accuracy of the CDT in identifying delirium in hospitalised older adults.Methods: PRISMA guidelines were used to report the identified studies. Pubmed, SCOPUS, and Ovid and EBSCO platforms (including MEDLINE ®, PsycINFO, PsycEXTRA, EMCARE, CINAHL and EMBASE databases) were searched. Studies were assessed for methodological quality using the Downs and Black Tool. Data were extracted regarding the number of delirious/not delirious, number with normal and abnormal CDT, age, and MMSE scores, and information regarding CDT scoring, criteria for diagnosis of delirium and setting of the study. Analysis was carried out with the "Mada" and "Metatron" packages of R software.Results: Fifteen studies were examined. The number of participants was 2199, of whom 597 (27.15%) were diagnosed with delirium. The overall sensitivity of CDT in the absence of any formal cognitive test was 0.76 (0.58-0.87) with specificity of 0.70 (0.51-0.83). When the MMSE was taken into account, the specificity and sensitivity reduced to 0.51. Diagnostic criteria for delirium, scoring method of CDT, age of participants and setting significantly (p < 0.05) affect the sensitivity and specificity of the CDT.Conclusion: Although, the CDT is generally considered to be a simple and easy to administer screening tool for cognitive impairment in older hospitalised adults, when a more formal cognitive test is used its sensitivity and specificity to detect delirium is low.

Psychological and Cognitive Markers of Behavioral Variant Frontotemporal Dementia-A Clinical Neuropsychologist's View on Diagnostic Criteria and Beyond

Behavioral variant frontotemporal dementia (bvFTD) is the second leading cognitive disorder caused by neurodegeneration in patients under 65 years of age. Characterized by frontal, insular, and/or temporal brain atrophy, patients present with heterogeneous constellations of behavioral and psychological symptoms among which progressive changes in social conduct, lack of empathy, apathy, disinhibited behaviors, and cognitive impairments are frequently observed. Since the histopathology of the disease is heterogeneous and identified genetic mutations only account for ~30% of cases, there are no reliable biomarkers for the diagnosis of bvFTD available in clinical routine as yet. Early detection of bvFTD thus relies on correct application of clinical diagnostic criteria. Their evaluation however, requires expertise and in-depth assessments of cognitive functions, history taking, clinical observations as well as caregiver reports on behavioral and psychological symptoms and their respective changes. With this review, we aim for a critical appraisal of common methods to access the behavioral and psychological symptoms as well as the cognitive alterations presented in the diagnostic criteria for bvFTD. We highlight both, practical difficulties as well as current controversies regarding an overlap of symptoms and particularly cognitive impairments with other neurodegenerative and primary psychiatric diseases. We then review more recent developments and evidence on cognitive, behavioral and psychological symptoms of bvFTD beyond the diagnostic criteria which may prospectively enhance the early detection and differential diagnosis in clinical routine. In particular, evidence on specific impairments in social and emotional processing, praxis abilities as well as interoceptive processing in bvFTD is summarized and potential links with behavior and classic cognitive domains are discussed. We finally outline both, future opportunities and major challenges with regard to the role of clinical neuropsychology in detecting bvFTD and related neurocognitive disorders.

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.

Validity and Clinical Utility of Different Clock Drawing Test Scoring Systems in Multiple Forms of Dementia

The Clock Drawing Test (CDT) has a known potential for the detection of cognitive impairment in populations with dementia, especially Alzheimer disease (AD). Our aim was to compare the clinical utility of 3 CDT scoring systems (Rouleau, Cahn, and Babins) in several pathologies with cognitive compromise from a tertiary center memory clinic. We selected patients with a clinical diagnosis of mild stage AD, behavioral variant frontotemporal dementia (FTD), vascular dementia (VaD), dementia with Lewy bodies (DLB), and Parkinson disease with dementia (PDD). The results showed significant differences between the several diagnoses with the following pattern of results: AD, DLB < FTD, VaD, PDD. Qualitative analysis of clock drawing errors confirmed the stimulus-bound response as a hallmark of AD, while conceptual deficit was significantly more prevalent in patients with AD and DLB. Our results supported the CDT potential as a cognitive screening measure for mild dementia, particularly sensitive to AD and DLB, especially when we used the Cahn scoring system and its analysis of qualitative errors.

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.

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

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

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Visuospatial tasks demonstrate significant diagnostic and prognostic potential.

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

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Novel topographical memory tasks demonstrated the greatest prognostic potential.

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.

Successes and failures in assessing cognitive function in older adults using video consultation

We investigated the level of agreement between specialists conducting a cognitive assessment via videoconference compared with a face-to-face assessment. The patient and doctor were linked via a videoconference system which was located within the same hospital. To assess inter-rater reliability, paired face-to-face assessments were also carried out. There were 42 subjects, who were aged over 50 years and who had not attended a memory disorder clinic in the previous 12 months. A battery of standardized cognitive assessments was performed by a trained clinic nurse, prior to the two assessments by separate specialists. The weighted kappa score for face-to-face inter-rater reliability was 0.53. The agreement between face-to-face and videoconferencing assessment was 0.63. The present study shows that the use of videoconferencing for cognitive assessment results in assessment outcomes similar to those from face-to-face assessment.

Executive Abilities as Reflected by Clock Hand Placement: Frontotemporal Dementia Versus Early-Onset Alzheimer Disease

The clock-drawing test (CDT) is widely used in clinical practice to diagnose and distinguish patients with dementia. It remains unclear, however, whether the CDT can distinguish among the early-onset dementias. Accordingly, we examined the ability of both quantitative and qualitative CDT analyses to distinguish behavioral variant frontotemporal dementia (bvFTD) and early-onset Alzheimer disease (eAD), the 2 most common neurodegenerative dementias with onset <65 years of age. We hypothesized that executive aspects of the CDT would discriminate between these 2 disorders. The study compared 15 patients with bvFTD and 16 patients with eAD on the CDT using 2 different scales and correlated the findings with neuropsychological testing and magnetic resonance imaging. The total CDT scores did not discriminate bvFTD and eAD; however, specific analysis of executive hand placement items successfully distinguished the groups, with eAD exhibiting greater errors than bvFTD. The performance on those executive hand placement items correlated with measures of naming as well as visuospatial and executive function. On tensor-based morphometry of the magnetic resonance images, executive hand placement correlated with right frontal volume. These findings suggest that lower performance on executive hand placement items occurs with involvement of the right dorsolateral frontal-parietal network for executive control in eAD, a network disproportionately affected in AD of early onset. Rather than the total performance on the clock task, the analysis of specific errors, such as executive hand placement, may be useful for early differentiation of eAD, bvFTD, and other conditions.

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.

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.

Mapping the clockworks: what does the Clock Drawing Test assess in normal and pathological aging?

The Clock Drawing Test (CDT) is a cognitive screening tool used in clinical and research settings. Despite its role on the assessment of global cognitive functioning, the specific cognitive components required for test performance are still unclear. We aim to assess the role of executive functioning, global cognitive status, visuospatial abilities, and semantic knowledge on Shulman's CDT performance. Fifty-three mild cognitive impairment, 60 Alzheimer's dementia, and 57 normal elderly controls performed the CDT, the Frontal Assessment Battery, the Mini-Mental State Examination, the Stick Design Test, and a naming test (TN-LIN). An ordinal regression assessed specific neuropsychological influences on CDT performance. All the cognitive variables were related to the CDT, accounting for 53% of variance. The strongest association was between the CDT and executive functions, followed by global cognitive status, visuospatial processing, and semantic knowledge. Our result confirms the multidimensional nature of the test and the major role of executive functions on performance.

[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.

[Cognitive function screening of community-dwelling elderly people using the clock drawing test -quantitative and qualitative analyses]

AIM

The purpose of this study was to evaluate whether the clock drawing test (CDT) is useful to assess the cognitive function of community-dwelling elderly people. We evaluated the CDT as a tool to measure cognitive function by qualitative and quantitative analyses.

METHODS

A total of 14,949 community-dwelling elderly were invited by mail to undergo cognitive screening by CDT. Of these, 8,815 responded, of which 8,684 were eligible for enrollment. We were also able to determine the educational background of 7,404 of these. There were 3,525 men (age: 73.05±6.20 [mean±standard deviation] years old, duration of education: 11.40±2.81 years) and 3,879 women (73.67±6.66, 10.34±2.19) . The drawn clocks were evaluated using the Freedman method, and those clocks drawn with obvious errors such as no circle, numbers, or hands were recorded and analyzed. In addition, any vertical deviation from the center points was also evaluated.

RESULTS

The recorded percentages of the subjects who correctly completed the individual clock drawing test components varied. The mean total scores were 14.16±1.67 in men and 14.40±1.36 in women. The percentages of subjects with total scores of less than 13 were 16.09% in men and 11.7% in women. The percentage of subjects who made obvious errors was 3.24%, whose total points were significantly lower than those of the subjects who did not. Approximately half of all subjects showed vertical deviation from the center of the clock, and the percentage of upper deviation was greater than that of lower deviation.

CONCLUSION

CDT is useful to assess the cognitive function of community-dwelling elderly people, and it is also helpful to determine subjects with a potential risk of cognitive impairments.

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.

Language, executive function and social cognition in the diagnosis of frontotemporal dementia syndromes

Frontotemporal dementia (FTD) represents a spectrum of non-Alzheimer's degenerative conditions associated with focal atrophy of the frontal and/or temporal lobes. Frontal and temporal regions of the brain have been shown to be strongly involved in executive function, social cognition and language processing and, thus, deficits in these domains are frequently seen in patients with FTD or may even be hallmarks of a specific FTD subtype (i.e. relatively selective and progressive language impairment in primary progressive aphasia). In this review we have attempted to delineate how language, executive function, and social cognition may contribute to the diagnosis of FTD syndromes, namely the behavioural variant FTD as well as the language variants of FTD including the three subtypes of primary progressive aphasia (PPA): non-fluent/agrammatic, semantic and logopenic. This review also addresses the extent to which deficits in these cognitive areas contribute to the differential diagnosis of FTD versus Alzheimer's disease (AD). Finally, early clinical determinants of pathology are briefly discussed and contemporary challenges to the diagnosis of FTD are presented.

A reduced scoring system for the Clock Drawing Test using a population-based sample

BACKGROUND

Many scoring systems exist for clock drawing task variants, which are common dementia screening measures, but all have been derived from clinical samples. This study evaluates and combines errors from two published scoring systems for the Clock Drawing Test (CDT), the Lessig and Tuokko methods, in order to create a simple yet optimal scoring procedure to screen for dementia using a Canadian population-based sample.

METHODS

Clock-drawings from 356 participants (80 with dementia, 276 healthy controls) from the Canadian Study on Health and Aging were analyzed using logistic regression and Receiver Operating Characteristic curves to determine a new, simplified, population-based CDT scoring system. The new Jouk scoring method was then compared to other commonly used systems (e.g. Shulman, Tuokko, Watson, Wolf-Klein).

RESULTS

The Jouk scoring system reduced the Lessig system even further to include five critical errors: missing numbers, repeated numbers, number orientation, extra marks, and number distance, and produced a sensitivity of 81% and a specificity of 68% with a cut-off score of one error. With regard to other traditionally used scoring methods, the Jouk procedure had one of the most balanced sensitivities/specificities when using a population-based sample.

CONCLUSIONS

The results from this study improve our current state of knowledge concerning the CDT by validating the simplified scoring system proposed by Lessig and her colleagues in a more representative sample to mimic conditions a general clinician or researcher will encounter when working among a wide-ranging population and not a dementia/memory clinic. The Jouk CDT scoring system provides further evidence in support of a simple and reliable dementia-screening tool that can be used by clinicians and researchers alike.

Tools to detect delirium superimposed on dementia: a systematic review

OBJECTIVES

To identify valid tools to diagnose delirium superimposed on dementia.

DESIGN

Systematic review of studies of delirium tools that explicitly included individuals with dementia.

SETTING

Hospital.

PARTICIPANTS

Studies were included if delirium assessment tools were validated against standard criteria, and the presence of dementia was assessed according to standard criteria that used validated instruments.

MEASUREMENTS

PubMed, Embase, and Web of Science databases were searched for articles in English published between January 1960 and January 2012.

RESULTS

Nine studies fulfilled the selection criteria. Of 1,569 participants, 401 had dementia, and 50 had delirium superimposed on dementia. Six delirium tools were evaluated. One study using the Confusion Assessment Method (CAM) with 85% of participants with dementia had high specificity (96-100%) and moderate sensitivity (77%). Two intensive care unit studies that used the CAM for the Intensive Care Unit (CAM-ICU) reported 100% sensitivity and specificity for delirium in 23 individuals with dementia. One study using electroencephalography reported sensitivity of 67% and specificity of 91% in a population with a 100% prevalence of dementia. No studies examined potential effects of dementia severity or subtype on diagnostic accuracy.

CONCLUSIONS

The evidence base on tools for detection of delirium superimposed on dementia is limited, although some existing tools show promise. Further studies of existing or refined tools with larger samples and more-detailed characterization of dementia are required to address the identification of delirium superimposed on dementia.

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.

Clock drawing in the Montreal Cognitive Assessment: recommendations for dementia assessment

BACKGROUND

Clock drawing is part of the Montreal Cognitive Assessment (MoCA) test but may have administration and scoring limitations. We assessed (1) the reliability of the MoCA clock criteria relative to a published error scoring approach, (2) whether command-only administration could distinguish dementia from cognitively intact individuals and (3) the value of adding a clock copy condition to the MoCA.

METHODS

Three novice raters and clocks from dementia and control participants were used to assess the 3 aims.

RESULTS

MoCA interrater and intrarater reliability were low (i.e. intraclass correlation coefficient = 0.12-0.31) and required repeat training. Clocks drawn to command classified dementia at chance. Inclusion of a copy condition demonstrated expected dementia subgroup patterns.

CONCLUSION

Reliable clock scoring with MoCA criteria requires practice. Supplementing a clock copy to the standard MoCA test (takes <1 min) will improve dementia assessment.

Longitudinal changes in clock drawing test (CDT) performance according to dementia subtypes and severity

The CDT requires a patient to draw the face of a clock, insert all the numbers and set the hands for a specified time. This task engages a number of cognitive abilities including verbal understanding, memory, spatially coded knowledge, planning, concentration and visuoconstructive skills. Although CDT has been regarded as a simple and useful screening tool in dementia, little is known about the longitudinal changes in CDT performance and error types, according to dementia subtypes and their severity.

MATERIALS AND METHODS

Two hundred thirty-five consecutive patients with dementia (Alzheimer disease = AD, n=94, Parkinson's disease with dementia (PDD), n = 119, Vascular dementia = VaD, n = 22) were recruited from the memory clinic at Chungnam University hospital from January 2005 to July 2009. The Korean version of the mini-mental state examination (MMSE-K) and CDT were performed by all participants every 6 months. Scoring of the CDT performance was in accordance with the method of Mano and Wu. Error types of CDT were classified as follows: stimulus-bound response (SBR), conceptual deficit (CD), spatial and/or planning deficit (SPD) and perseveration error (PE). We divided patients into 3 groups by their initial MMSE-K score (severe, MMSE-K ≤ 17; moderate, 18 ≤ MMSE-K < 24; mild, 24 ≤ MMSE-K). Comparisons of CDT scores and error types in the three dementia subtypes and three cognitive groups were conducted.

RESULTS

Longitudinal changes on CDT and MMSE-K scores were not different between the three dementia subtypes. From the analysis of CDT error type, the most common error type was SPD in patients with mild to moderate dementia. In contrast, CD error was the most frequent in severe dementia group. The order of error frequency in all subjects from baseline to the last follow-up was as follows: SPD, CD, SBR and PE except CD was the most frequent error type in AD patients after 18 months from baseline.

CONCLUSION

Longitudinal analysis of error on CDT may reflect different characteristics of cognitive deterioration according to dementia subtypes and dementia stages.

Screening and case-finding tools for the detection of dementia. Part II: evidence-based meta-analysis of single-domain tests

AIM

To evaluate the diagnostic validity of single-domain cognitive tests for detecting dementia. These methods were defined as those that focus mainly on one domain of cognitive function such as orientation, memory, or executive function.

METHODS

A meta-analysis of robust studies was conducted. There were 15 categories of single-domain methods assessed in 45 analyses, including 27 performed head-to-head against the Mini-Mental State Examination (MMSE). Thirteen studies took place in community settings, 9 in primary care, and 23 in specialist settings.

RESULTS

In community settings, single-domain cognitive tests helped detect 64.2% of all dementias. In this setting, specificity (Sp) was 84.9%, positive predictive value (PPV) was 57.1%, and negative predictive value (NPV) was 88.3%. This was significantly less accurate than the MMSE itself. The optimal individual method was the memory impairment screen (MIS). In primary care, the sensitivity (Se) and specificity of single-domain tests were 69.5% and 82.5%, respectively. The PPV and NPV were 36.5% and 95.8%. Considered together, these methods were less specific but equally sensitive as the MMSE when applied in primary care. Here, the most successful methods were the selective reminding test (SRT) and clock drawing test, the latter having data from independent samples. In specialist settings, single-domain methods had a Se of 76.6%, a Sp of 81.9%, a PPV 80.8%, and a NPV 74.9%. This represented almost equivalent accuracy to the MMSE. The optimal method for specialist settings (based on accuracy alone) was the memory alteration test.

CONCLUSION

Brief single-domain methods offer diagnostic performance for detection of dementia that is surprisingly close to that offered by cognitive batteries such as the MMSE. As a method of screening or as part of a diagnostic algorithm, brief single-domain tests may be an efficient first step in identifying cognitive impairment.

[Negative response bias and assessment of uncooperativeness in independent medical evaluations]

The present article highlights how simple it appears to be to simulate symptoms and how often medical and forensic experts are unable or unwilling to properly identify such attempts at deception. Yet, experts usually lack a critical understanding of the limitations of their own powers of judgement. Although carefully developed and reliable approaches and procedures are available today to verify the validity of symptoms, these are often applied unwillingly. Despite sound base-rate estimates, cooperativeness in forensic evaluations is often accepted without proper critical assessment. In German speaking countries, more empirical research on civil forensic assessment would help to improve the quality of expert opinions.

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 in cognitively normal elderly

The Clock Drawing Test (CDT) is a common neuropsychological measure sensitive to cognitive changes and functional skills (e.g., driving test performance) among older adults. However, normative data have not been adequately developed. We report the distribution of CDT scores using three common scoring systems [Mendez, M. F., Ala, T., & Underwood, K. L. (1992). Development of scoring criteria for the Clock Drawing Task in Alzheimer's Disease. Journal of the American Geriatrics Society, 40, 1095-1099; Cahn, D. A., Salmon, D. P., Monsch, A. U., Butters, N., Wiederholt, W. C., & Corey-Bloom, J. (1996). Screening for dementia of the Alzheimer type in the community: The utility of the Clock Drawing Test. Archives of Clinical Neuropsychology, 11(6), 529-539], among 207 cognitively normal elderly. The systems were well correlated, took little time to use, and had high inter-rater reliability. We found statistically significant differences in CDT scores based on age and WRAT-3 Reading score, a marker of education quality. We present means, standard deviations, and t- and z-scores based on these subgroups. We found that "normal" CDT performance includes a wider distribution of scores than previously reported. Our results may serve as useful comparisons for clinicians wishing to know whether their patients perform in the general range of cognitively normal elderly.

Cognitive-behavioral profiles of neurodegenerative dementias: beyond Alzheimer's disease

The neurocognitive and behavioral profiles of vascular dementia and vascular cognitive impairment, dementia with Lewy bodies and Parkinson's disease with dementia, and dementia syndromes associated with frontotemporal lobar degenerations are compared and contrasted with Alzheimer's dementia (AD). Vascular dementia/vascular cognitive impairment is characterized by better verbal memory performance, worse quantitative executive functioning, and prominent depressed mood. Dementia with Lewy bodies and Parkinson's disease with dementia are equally contrasted with AD by defective processing of visual information, better performance on executively supported verbal learning tasks, greater attentional variability, poorer qualitative executive functioning, and the presence of mood-congruent visual hallucinations. The frontal variant of frontotemporal lobar degeneration (frontotemporal dementia) differs from AD by better multimodal retention on learning tasks, different patterns of generative word fluency, defective qualitative executive functioning, and by markedly impairment of comportment. For temporal variants of frontotemporal lobar degenerations, progressive aphasia and semantic dementia, worse language performance relative to AD is typically characteristic.

Frontotemporal dementia in Oman: Cognitive behavioural profile and neuroimaging characteristics; A prospective hospital-based study

Frontotemporal dementia is increasingly recognised as an important cause of early-onset dementia and is considered to be the second commonest neurodegenerative dementia after Alzheimer's disease. We describe the cognitive, behavioural profile and neuroimaging characteristics of 6 patients with frontal variant of Frontotemporal dementia that were evaluated at the cognitive behavioural clinic at this tertiary referral teaching hospital. All patients underwent clinical, neuropsychological, structural/functional neuroimaging, and laboratory evaluations. The male to female ratio was 1:1; mean age of onset was 54 years, and the mean duration of symptoms were 30 months. The mean scores for Addenbrooke's cognitive examination, Frontal Assessment Battery, and Mini-Mental State Examination were 70.5, 6.33 and 23.6 respectively. The mean VLOM ratio was 2.04. MRI revealed significant asymmetrical regional frontal/temporal atrophy supplemented by the evidence of circumscribed hypoperfusion in SPECT imaging. We conclude that a combination of behavioural and cognitive assessment using short bedside tests, along with structural and functional neuroimaging does facilitate early identification, and increase the diagnostic specificity of Frontotemporal dementia.

Neuropsychological deficits in frontotemporal dementia and Alzheimer's disease: a meta-analytic review

We sought to identify the cognitive tests that best discriminate between Alzheimer's disease (AD) and frontotemporal dementia (FTD). A comprehensive search of all studies examining the cognitive performance of persons diagnosed with AD and FTD, published between 1980 and 2006, was conducted. Ninety-four studies were identified, comprising 2936 AD participants and 1748 FTD participants. Weighted Cohen's d effect sizes, percentage overlap statistics, confidence intervals and fail-safe Ns were calculated for each cognitive test that was used by two or more studies. The most discriminating cognitive tests were measures of orientation, memory, language, visuomotor function and general cognitive ability. Although there were large and significant differences between groups on these measures, there was substantial overlap in the scores of the AD and FTD groups. Age, education, years since diagnosis and diagnostic criteria did not significantly contribute to the group differences. Given the large overlap in the test performance of persons diagnosed with AD and FTD, cognitive tests should be used cautiously and in conjunction with a medical history, behavioural observations, imaging and information from relatives when making differential diagnoses.

The elephant in the room - healthy brains in later life, epidemiology and public health

The increasing age of the population around the world has meant that greater attention is being paid to disorders that mainly affect older people. In particular, work is focusing on ways to preserve the healthy brain and prevent dementia. Preventive studies are complex and must take into account not only simple approaches such as those used in risk and outcome studies, but also stage of life, survival and mortality, and population context before their effect can be assessed. This paper presents questions and areas which must be explored if the potential for prevention of dementia during brain ageing is to be properly understood.