Improvement pattern in the clock drawing test in early Alzheimer's disease

OBJECTIVE: The aim of this paper was to compare the performance of a group of patients with early Alzheimer's disease (EAD) against a control group of healthy control (HC) subjects in the Clock Drawing Test (CDT), i.e. verbal command versus copying of a clock model presented to the subject. PATIENTS AND METHODS: The authors have studied 140 subjects; 70 patients with probable EAD, with a mean age of 76.4 +/- 7.64 years and a clinical dementia rating stage 1 (mild dementia), and 70 HC with a mean age of 75.16 +/- 6.34 years. RESULTS: Patients in the EAD group obtained significantly higher scores on the copy command mode than on the verbal command mode (Z = -7.129, p < 0.001)--improvement pattern of the CDT--whereas no statistically significant differences were found in the HC group (Z = -2.001, p < 0.080). Within the group of EAD patients, we have noticed that there is a correlation between the copy command mode and the visual-constructive functions of the Cambridge Cognitive Examination (CAMCOG) (r = 0.607, p < 0.01), while the memory functions of the CAMCOG correlate with the verbal command mode (r = 0.704, p < 0.01). CONCLUSIONS: In our study, the EAD patients show an improvement pattern in the execution of the CDT copy command in comparison with the execution of the CDT verbal command, which we did not observe in the HC group. Such results might be associated with a greater deterioration of the memory functions when compared with the visual-constructive ones in the patients with EAD.     

Cortical signature of clock drawing performance in Alzheimer's disease and mild cognitive impairment

It is unclear whether clock drawing test (CDT) performance relies on a widely distributed cortical network, or whether this test predominantly taps into parietal cortex function. So far, associations between cortical integrity and CDT impairment in Alzheimer's disease (AD) and mild cognitive impairment (MCI) largely stem from cortical volume analyses. Given that volume is a product of thickness and surface area, investigation of the relationship between CDT and these two cortical measures might contribute to better understanding of this cognitive screening tool for AD. 38 patients with AD, 38 individuals with MCI and 31 healthy controls (HC) underwent CDT assessment and MRI at 3 Tesla. The surface-based analysis via Freesurfer enabled calculation of cortical thickness and surface area. CDT was scored according to the method proposed by Shulman and related to the two distinct cortical measurements. Higher CDT scores across the entire sample were associated with cortical thickness in bilateral temporal gyrus, the right supramarginal gyrus, and the bilateral parietal gyrus, respectively (p < 0.001 CWP corr.). Significant associations between CDT and cortical thickness reduction in the parietal lobe remained significant when analyses were restricted to AD individuals. There was no statistically significant association between CDT scores and surface area (p < 0.001 CWP corr.). In conclusion, CDT performance may be driven by cortical thickness alterations in regions previously identified as “AD vulnerable”, i.e. regions predominantly including temporal and parietal lobes. Our results suggest that cortical features of distinct evolutionary and genetic origin differently contribute to CDT performance.     

Brain structural and cognitive correlates of clock drawing performance in Alzheimer's disease.

The Clock Drawing Test (CDT) is widely used in the assessment of dementia and is known to be sensitive to the detection of deficits in neurodegenerative disorders such as Alzheimer's disease (AD). CDT performance is dependent not only on visuospatial and constructional abilities, but also on conceptual and executive functioning; therefore, it is likely to be mediated by multiple brain regions. The purpose of the present study was to identify component cognitive processes and regional cortical volumes that contribute to CDT performance in AD. In 29 patients with probable AD, CDT performance was significantly related to right-, but not left-hemisphere, regional gray matter volume. Specifically, CDT score correlated significantly with the right anterior and posterior superior temporal lobe volumes. CDT scores showed significant relationships with tests of semantic knowledge, executive function, and visuoconstruction, and receptive language. These results suggest that in AD patients, CDT performance is attributable to impairment in multiple cognitive domains but is related specifically to regional volume loss of right temporal cortex.     

CERAD test performances in amnestic mild cognitive impairment and Alzheimer's disease

OBJECTIVES: The aim of the study was to examine the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) test performances cross-sectionally in patients suffering from amnestic mild cognitive impairment (MCI) and mild Alzheimer's disease (AD). Moreover, we wanted to determine the sensitivity to amnestic MCI and mild AD, as well as the specificity of different CERAD subtests in our study groups. MATERIAL AND METHODS: Fifteen healthy elderly individuals, 15 amnestic MCI patients and 15 probable AD patients suffering from mild dementia were tested with the CERAD neurocognitive dementia screening test. RESULTS: Significant differences were found in all CERAD tests except Constructional praxis (copy) and Clock drawing between the controls and the AD group. The MCI group was differentiated from the controls only in the Wordlist learning test. In the language tests the sensitivity to MCI and AD was quite low and the specificity very high. In the savings scores the sensitivity to AD was high, but the specificity rather low. The Wordlist recognition test screened no false positives using the current cut-off score and the sensitivity to AD was 0.6, but only one MCI patient was detected using the current cut-off score. Raising the cut-off score also raised the sensitivity to MCI without dramatic loss of specificity. Cut-off scores for the Wordlist learning test and Wordlist delayed recall, which have been found to differentiate normal aging from dementia, are lacking in the Finnish CERAD. The current data indicates that the Wordlist learning test might be relatively sensitive to MCI. CONCLUSIONS: The results indicate that the Finnish CERAD test battery with its current cut-off scores has low sensitivity to MCI, and using it as a sole cognitive screening instrument for MCI and preclinical dementia might result in false negatives.     

Quantitative digital clock drawing test as a sensitive tool to detect subtle cognitive impairments in early stage Parkinson's disease

IntroductionThe prevalence of subtle cognitive decline in the early stages of Parkinson's Disease (PD) is common and is thought to be even greater in patients carrying genetic mutations in the GBA gene. Current cognitive tests often lack sensitivity to identify subtle impairments. Technological advancements may offer greater precision. We explored the utility of a digitized cognitive clock-drawing test to assess cognition in patients with PD compared to healthy controls (HC) and its sensitivity compared to that of standardized neuropsychological tests. Further, we investigated the existence of a cognitive profile based on genotype.MethodsThe study included 75 early stage PD patients (24 with GBA-PD, 23 LRRK2-PD, 28 idiopathic PD cases) and 59 HC. Participants underwent a cognitive assessment which included the Montreal Cognitive Assessment (MoCA), the Color Trails Test (CTT) and a digital clock drawing test (DCTclock).ResultsPatients with PD presented lower scores than HC on all cognitive tests. The DCTclock best discriminated PD from HC (AUC: 0.807) compared to the MoCA (0.590) and CTT (0.636 and 0.717 for CTT-1 and CTT-2 respectively). In-depth quantitative analysis of the DCTclock revealed that LRRK2-PD showed better performance than other PD sub-groups.ConclusionThe use of quantitative digital cognitive assessment showed greater sensitivity in identifying subtle cognitive decline than the current standardized tests. Differences in cognitive profiles were observed based on genotype. The identification of early cognitive decline may improve the clinical management of PD patients and be useful for cognitive related clinical trials.     

Neural correlates of impaired performance on the clock drawing test in Alzheimer's disease

To identify the neural correlates for impaired performance on the clock drawing test (CDT) in patients with Alzheimer's disease (AD), we examined the relationship between the CDT performances and the regional cerebral blood flow (rCBF) in 100 AD patients. The patients were equally divided into a mildly impaired CDT group, a severely impaired CDT group, and two normal CDT groups, with age and dementia severity matched. Between-group comparisons revealed that rCBF reduction in the posterolateral region of the left temporal lobe was consistently associated with mild to severe impairment of the CDT in AD. Correlation analysis also showed that the rCBF in the left posterolateral temporal cortex was linearly correlated with CDT performance. The CDT scores in AD were significantly improved for the copy condition relative to the drawing-to-command condition. These findings suggest that CDT performance has a close relationship with the left posterior temporal function, and that semantic memory deficit may at least partly contribute to impaired CDT performance in AD.     

Screening for early cognitive impairment in multiple sclerosis patients using the clock drawing test

The clock drawing test (CDT) is a complex task assessing integrative functions, abstract thinking and visuospatial organization. In the present study we evaluated the CDT as a possible screening instrument for early cognitive impairment in multiple sclerosis (MS) patients. In total, 107 MS patients completed the CDT as well as a battery assessing five cognitive domains. There were 73 female and 34 male participants (mean age 45.4+/-11.6 years, range 19-69). The majority (76/107) were diagnosed with a relapsing-remitting disease course. Mean expanded disability status scale (EDSS) score was 4.3+/-2.4 (range 0-8). The CDT was scored on a 1-6 point scale with "1" being a perfect score and "6" reflecting severe disorganization. Mean CDT score was 2.6+/-1.4. In 53% of patients the CDT was normal while in 11.2% dementia was apparent. The CDT score did not correlate with the total EDSS. Significant correlations were obtained with the mental functional system score of the EDSS (r = 0.78; p = 0.0001), visual learning and recall, sustained attention and concentration. Our findings demonstrate the sensitivity of the CDT to several cognitive domains. The absence of correlation with total EDSS score coupled with significant correlation with the mental functional system suggests that the CDT may be useful for screening MS patients.     

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.     

The clock drawing test as a valid screening method for mild cognitive impairment

To validate the Clock Drawing Test (CDT) as a screening method for detecting mild cognitive impairment (MCI) and to find the appropriate scoring protocol and its cutoff point, we compared the sensitivity and specificity of three CDT protocols. Subjects included 219 outpatients with memory complaints, who were attending the geriatric memory clinic. Cahn's protocol, with a cutoff point of 7, was more successful at differentiating clinically diagnosed MCI subjects from normal elderly individuals, with higher sensitivity (74.7%) and specificity (75.6%), than were the other protocols. The CDT, as a handy screening method, may be useful for clinicians to reliably identify subjects with MCI, and it may contribute to early detection of dementia.     

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

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

Encoding specificity, depth of processing, and cued recall in Alzheimer's disease

Unlike normal aging, Alzheimer's disease (SDAT) subjects typically show no benefit in free recall from semantic depth of processing cues at acquisition, but their recall is enhanced by semantic cues at both acquisition and retrieval. However, this apparent encoding-specificity effect might result from cued recall alone. SDAT and control subjects studied pictures in a design comparing depth of processing, cued recall, and encoding specificity. Cued recall alone was ineffective for SDAT subjects but, consistent with other studies, the encoding specificity condition did enhance recall. Both control and SDAT subjects also showed a levels of processing effect in free recall, modified by recency of presentation. Conclusions were: (a) though impaired in the capacity spontaneously to do so, SDAT subjects can be assisted to exploit semantic aspects of material in memory; (b) for optimal remembering in SDAT, substantial cued support should be provided at both ends of the processing continuum.     

画钟测验对轻度阿尔茨海默病的诊断作用

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

Evaluation of cognitive dysfunction by the clock drawing test in multiple sclerosis and clinically isolated syndrome patients: Correlation with other neuropsychological tests

Objectives:To evaluate the cognitive status with a simple practical test, clock drawing test (CDT), in a larger multiple sclerosis (MS) patient group and in comparison, with controls.Methods:We included 171 patients (17–65 years) with MS and clinically isolated syndrome (CIS) and 98 healthy controls who applied between date 2018-2020 years in Neurology Department of Pamukkale University. The CDTs were applied to all subjects. In addition, the cognitive functions of the patient group were evaluated with the neuropsychological test battery.Results:The CDT scores were significantly lower in relapsing-remitting MS (RRMS) group than the control group (p<0.005). Progressive MS patients’ CDT scores were significantly lower than RRMS and CIS (p<0.0001). According to our results, the CDT showed progressive deterioration in MS better than another practical and free tests. Additionally, the CDT scores were statistically better in patients whose disease began with sensory symptoms than whose disease started with motor and brainstem symptoms (p<0.0001).Conclusion:The CDT cognitive impairment prediction performance is 60%, CDT is a useful, easy-to-administer, practical test that can be used in cognitive assessment in MS and CIS.

In multiple sclerosis (MS), cognitive impairment can be seen in the early period independently of neurological deficits. This situation causes many challenges, including morbidity, problems with work, and social dysfunction. The cognitive destruction in the early period occurs due to axonal loss secondary to inflammation and the neurodegenerative process in white and grey matter effected in the temporal and frontal cortex. ^1,2 Hence, both white and grey matter are responsible for cognitive impairments. In MS, particularly learning, memory, conceptual reasoning, speed of information processing, attention, and executive functions are affected, but language functions like fluency, repetition, and expression are generally preserved. ³ Multiple factors like age, disease duration, disease course, affective disturbance, and disability can change cognitive status without clear correlation. Some studies have shown that with the increase of disease duration, cognitive deterioration can be seen. However, in several studies the cognitive process-time relationship has not been demonstrated. ⁴ Therefore, even if the duration of the disease is short and the neurological deficit is minimal, a neuropsychological evaluation should be performed in the early stage. However, it is very important to be able to do this with a short, reliable, practical, and cost-effective test. The MMSE desktop test, which is very commonly used, is not sensitive enough. Although neuropsychological tests are very sensitive and specific, they are not practical because they take a long time and are not cost-effective. The clock drawing test (CDT) is a useful test in terms of abstract thinking, integrative functions, and visuo-spatial construction. ⁵ Barak et al ⁶ reported the sensitivity of the CDT as 93.4% and the specificity as 85.8% in early cognitive evaluation in MS. The CDT is an effective and practical method, since it evaluates the wide spectrum of cognitive functions and is not affected by the language, ethnicity, and educational background of individuals. ⁷ We already know that the CDT was used to evaluate cognition in people with MS in small groups ⁸ and without controls. ⁶ However, in our study, we aimed to evaluate the effect of the CDT on cognition in comparison with neuropsychological tests in larger patients and healthy control groups and at the onset of symptoms of the disease.     

Comparison of a clock drawing test in elderly schizophrenia and Alzheimer's disease patients: a preliminary study

The objective of this study was to compare between the quantitative and qualitative aspects of a clock drawing test in elderly schizophrenic and Alzheimer's disease (AD) patients. Three independent raters performed a retrospective analysis of the clock drawing item from the Cambridge Cognitive Examination (CAMCOG), in long-term open wards of a public psychiatric hospital and an outpatient psychogeriatric clinic. The study group comprised 21 elderly schizophrenic patients ('graduates') and 21 AD patients matched for gender and education, and cognitive impairment confirmed by a Folstein mini-mental state examination (MMSE) score of 18-23. The Clock Drawing Interpretation Scale (CDIS) was the measure used. Schizophrenic patients were significantly younger than AD patients (63.5 versus 81.3 years, p<0.0001), however, similar concerning gender, education, MMSE and CAMCOG scores. CDIS scores were not correlated with age in eight group. Inter-rater reliability was high (range 0.84-0.97). No significant differences between patient groups were found in mean CDIS total scores. A CDIS specific item analysis revealed that schizophrenic patients were significantly less impaired than AD patients on three out of 20 items: Number 7 (most symbols are aligned in a clockwise or a rightward direction). Number 8 (all symbols are totally within a closure figure), and Number 13 (numbers do not go beyond 12). Although schizophrenic patients and AD patients had similar total scores on the clock drawing test, they differed on specific test items related to spatial/planning deficit and preservation.