Qualitative Features of Clock Drawings in Normal Aging and Alzheimer's Disease

Dissociating Statistically Determined Normal Cognitive Abilities and Mild Cognitive Impairment Subtypes with DCTclock

OBJECTIVE

To determine whether the DCTclock can detect differences across groups of patients seen in the memory clinic for suspected dementia.

METHOD

Patients (n = 123) were classified into the following groups: cognitively normal (CN), subtle cognitive impairment (SbCI), amnestic cognitive impairment (aMCI), and mixed/dysexecutive cognitive impairment (mx/dysMCI). Nine outcome variables included a combined command/copy total score and four command and four copy indices measuring drawing efficiency, simple/complex motor operations, information processing speed, and spatial reasoning.

RESULTS

Total combined command/copy score distinguished between groups in all comparisons with medium to large effects. The mx/dysMCI group had the lowest total combined command/copy scores out of all groups. The mx/dysMCI group scored lower than the CN group on all command indices (p < .050, all analyses); and lower than the SbCI group on drawing efficiency (p = .011). The aMCI group scored lower than the CN group on spatial reasoning (p = .019). Smaller effect sizes were obtained for the four copy indices.

CONCLUSIONS

These results suggest that DCTclock command/copy parameters can dissociate CN, SbCI, and MCI subtypes. The larger effect sizes for command clock indices suggest these metrics are sensitive in detecting early cognitive decline. Additional research with a larger sample is warranted.

The Neural Correlates of the Clock-Drawing Test in Healthy Aging

Importance: The clock-drawing test (CDT) is an important neurocognitive assessment tool, widely used as a screening test for dementia. Behavioral performance on the test has been studied extensively, but there is scant literature on the underlying neural correlates.

Purpose: To administer the CDT naturalistically to a healthy older aging population in an MRI environment, and characterize the brain activity associated with test completion.

Main Outcome and Measure: Blood-oxygen-level dependent (BOLD) functional MRI was conducted as participants completed the CDT using novel tablet technology. Brain activity during CDT performance was contrasted to rest periods of visual fixation. Performance on the CDT was evaluated using a standardized scoring system (Rouleau score) and time to test completion. To assess convergent validity, performance during fMRI was compared to performance on a standard paper version of the task, administered in a psychometric testing room.

Results: Study findings are reported for 33 cognitively healthy older participants aged 52–85. Activation was observed in the bilateral frontal, occipital and parietal lobes as well as the supplementary motor area and precentral gyri. Increased age was significantly correlated with Rouleau scores on the clock number drawing (R2) component (rho = -0.55, p < 0.001); the clock hand drawing (R3) component (rho = -0.50, p < 0.005); and the total clock (rho = -0.62, p < 0.001). Increased age was also associated with decreased activity in the bilateral parietal and occipital lobes as well as the right temporal lobe and right motor areas.

Conclusion and Relevance: This imaging study characterizes the brain activity underlying performance of the CDT in a healthy older aging population using the most naturalistic version of the task to date. The results suggest that the functions of the occipital and parietal lobe are significantly altered by the normal aging process, which may lead to performance decrements.

Cognitive impairment in Parkinson's disease, Alzheimer's dementia, and vascular dementia: the role of the clock-drawing test

AIM

Cognitive impairment is present in several neurodegenerative disorders. The clock-drawing test (CDT) represents a useful screening instrument for assessing the evolution of cognitive decline. The aim of this study was to investigate the sensitivity of the CDT in monitoring and differentiating the evolution of cognitive decline in Alzheimer's dementia (AD), vascular dementia (VaD), and Parkinson's disease (PD).

METHODS

This study involved 139 patients, including 39 patients with PD and mild cognitive impairment, 16 demented PD patients, 21 VaD patients with mild cognitive impairment, 17 patients with VaD, 33 patients with mild cognitive impairment due to AD, and 13 patients with probable AD. All participants completed the CDT. The Mini-Mental State Examination was administered to establish patients' cognitive functioning.

RESULTS

Comparisons of quantitative and qualitative CDT scores showed significant differences between the various diseases. Impairment of executive functioning seems to be more pronounced in PD and VaD than in AD. Patients with AD committed more errors related to a loss of semantic knowledge, indicating a severely reduced capacity in abstract and conceptual thinking.

CONCLUSION

Results support the usefulness and sensitivity of the CDT in the detection of different dementia subtypes. Qualitative error analysis of the CDT may be helpful in differentiating PD, VaD, and AD, even in the early stages of each disease.

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.

Multiple clock drawing scoring systems: simpler is better

OBJECTIVE

The clock drawing test (CDT) is a widely used cognitive screening tool that has been well accepted among clinicians and patients for its ease of use and short administration time. Although there is ample interest in the CDT as a screening instrument, there remains a range of CDT administration and scoring systems with no consensus on which system produces the most valid results while remaining user friendly. The aims of this review are to synthesize the available evidence on CDT scoring systems' effectiveness and to recommend which system is best suited for use at the clinical frontlines.

DESIGN

A Pubmed literature search was carried out from 2000 to 2013 including manual cross-referencing of bibliographies in order to capture studies published after Shulman's comprehensive review published in 2000. A brief summary of all original scoring systems is included, as well as a review of relevant comparative studies.

RESULTS

The consensus from multiple comparison studies suggests that increasing the complexity of CDT scoring systems does little to enhance the test's ability to identify significant cognitive impairment. Moreover, increased complexity in scoring adds to the administration time, thereby reducing the test's utility in clinical settings.

CONCLUSIONS

In comparing scoring systems, no system emerged as consistently superior in terms of predictive validity. The authors conclude that when scoring the CDT as a screening instrument in a primary/general medicine/community setting, simpler is better, and perhaps qualitative assessment of "normal" versus "abnormal" may be sufficient for screening purposes and the establishment of a baseline for follow-up.

Brain activity during the Clock-Drawing Test: multichannel near-infrared spectroscopy study

The Clock-Drawing Test (CDT) is widely used in clinical practice for the screening of dementia. However, neural activity during real clock drawing has not been investigated due to motion artifacts. In the present study, we examined brain activity during real clock drawing using multichannel near-infrared spectroscopy (NIRS). We measured hemoglobin concentration changes in the prefrontal and temporal surface areas during clock drawing using 52-channel NIRS. Data obtained from 37 right-handed healthy volunteers were analyzed. We found significant increases in oxy-Hb in more than 96.2% of the channels (false-discovery rate corrected, p < .025). The time required for CDT performance showed a negative correlation with changes in oxy-Hb in the prefrontal region (r = -.529, p = .002). The mean value for oxy-Hb changes was higher in the left hemisphere in 20 subjects (54%) and in the right hemisphere in 17 subjects (46%). The NIRS/CDT combination is acceptable as a clinical tool, as the method has the advantages of direct measurement of cortical activation with high temporal resolution. Our results confirm the aspects of the CDT involving the frontal-lobe battery.

Videoconference diagnosis and management of Choctaw Indian dementia patients

BACKGROUND

This study reports a 5-year experience using videoconference (VC) technology in diagnosing and treating adult members of the Choctaw Nation with symptoms or complaints of cognitive impairment.

METHODS

Patients were given the option of a VC session or a face-to-face evaluation in the clinic. Before their VC session, patients underwent neuropsychological testing, Clinical Dementia Rating, Geriatric Depression Scale and Neuropsychiatric Inventory, brain computed tomography, and routine blood tests. Physical observations made by VC included eyesight, hearing, facial expression, gait and station, coordination, tremor, rapid alternating movements, psychomotor activity, and motor tests of executive function. Cogwheeling and rigidity were tested by our on-site nurse, who also obtained vital signs as indicated.

RESULTS

Between January 2005 and March 2010, there were 47 clinics, 171 visits, and 85 unique patients. There were 52 new evaluations and 119 follow-up visits. The number of visits ranged from one to eight and the length of follow-up from 1 month to 4.5 years. The no-show rate for all VC sessions in 2009 was 3%, and only two subjects in 5 years refused further VC visits.

CONCLUSION

Once cultural barriers are dealt with, VC-based diagnosis and treatment of adults with cognitive disorders who live in remote areas is feasible and well accepted by patients and families.

Contemporary review 2009: cognitive aging

This article addresses key topics in cognitive aging, intending to provide the reader with a brief overview of the current state of research in this growing, multidisciplinary field. A summary of the physiological changes in the aging brain is provided as well as a review of variables that influence cognitive abilities in older age. Normal aging differentially affects various aspects of cognition, and specific changes within various domains such as attention, executive functioning, and memory are discussed. Various theories have been proposed to account for the cognitive changes that accompany normal aging, and a brief examination of these theories is presented in the context of these domain-specific changes.

Factor analysis of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) in a large sample of patients suspected of dementia

The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS; Randolph, 1998) is a popular neuropsychological assessment instrument with research supporting its clinical utility. However, the index structure of the RBANS was derived theoretically and was not based on factor analysis. The purpose of this study was to examine the factor structure in a large heterogeneous sample of patients referred for a dementia evaluation, using exploratory factor analysis. Results suggest a two-factor solution, the first factor defined predominantly as a memory factor and the second as predominantly a visuospatial factor. This study also sought to validate the obtained factors by examining their relationship with external neuropsychological variables. Correlations between the external variables provide further support for Factor 1 as a memory factor. Correlations with Factor 2 support its visuospatial features, although this factor may also be associated with other cognitive domains such as attention and general ability.

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.

Cognitive and psychological issues in emphysema

Various psychological and cognitive difficulties have been documented in patients with emphysema. The aim of this article is to review prior literature on the prevalence of these difficulties in emphysema, as well as identify specific studies demonstrating improvement in these areas after therapy. Traditional therapies such as continuous and intermittent oxygen therapy and comprehensive pulmonary rehabilitation are reviewed. In general, these studies demonstrate reductions in symptoms of depression and anxiety as well as specific improvements in complex attention and verbal fluency. In a more recent study, patients with emphysema who underwent lung volume reduction surgery (LVRS) demonstrated improved psychomotor speed, verbal memory, and naming skills at 6 months compared with patients with emphysema who were in comprehensive rehabilitation only. The patients with emphysema who had LVRS also demonstrated greater decline in depressive symptoms compared with the rehabilitation patients at 6 months. There were no associations between improved neuropsychological tests and changes in depression, exercise tests, pulmonary function, oxygenation, or quality of life scores, and thus the mechanism of behavioral improvement identified in the patients who underwent LVRS remained unclear. Overall, studies suggest that psychological and cognitive improvements occur subsequent to a variety of medical and behavioral treatment therapeutic approaches, and that LVRS appears to have an advantage for some patients with emphysema.

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.

A study design to assess the safety and efficacy of on-pump versus off-pump coronary bypass grafting: the ROOBY trial

Background Since the late 1960s, coronary artery bypass graft (CABG-only) procedures were traditionally performed using a heart-lung machine on an arrested heart (on-pump). Over the past decade, an increasing number CABG-only procedures were performed on a beating heart (off-pump). Advocates of the off-pump approach expect to reduce many of the adverse side effects related to using the heart-lung machine, while advocates for the on-pump procedure raise concerns related to graft patency rates and long-term event-free survival for the off-pump technique.

Purpose The U.S. Department of Veteran Affairs (VA) Cooperative Studies Program funded a randomized, multicenter clinical trial comparing the clinical and resourcerelated outcomes following on-pump versus off-pump techniques for veterans undergoing a non-emergent CABG-only procedure. The planning committee was faced with several critically important challenges to assure feasibility of study costs and required sample size; generalizability to non-VA surgical practices; and comparability of clinically meaningful results. These challenges are discussed.

Methods This study is a prospective, randomized, multicenter, single blinded (patient) clinical trial that compares on-pump and off-pump techniques for veterans requiring non-emergent CABG-only procedures. There will be 2200 patients randomized at 17 VA Medical Centers when the five-year recruitment period ends on 15 April 2007. There are two primary objectives: a short-term objective to assess the immediate impact of the two techniques on 30-day mortality/morbidity and a long-term objective to assess one-year mortality/morbidity. Major secondary outcomes are one-year graft patency rates and change in neuropsychological assessments from baseline to one year. All patients are assessed at 30 days post-surgery or discharge from the hospital, whichever is latest, and at one-year post-surgery.

Results During planning, several key issues had to be decided. These included 1) choosing primary objectives: a short-term (30-day) and a long-term (one-year) objective were chosen; 2) choosing primary outcome measures: composite measures were selected to ensure sufficient end-points; 3) standardization of surgical techniques: minimal standardization required but guidelines and continuing discussions on both techniques provided; 4) establishing criteria for surgeons and residents for participation: surgeons required to have completed 20 off-pump procedures prior to doing study procedures and residents, in presence of study surgeon, capable of doing either procedure; 5) identifying metrics of cognitive dysfunction sensitive to treatment: a neuropshychologist hired who centrally monitors cognitive functioning testing; and 6) blinding participants of surgical procedure: attempt to blind participants.

Limitations Areas of concern are whether all surgeons sufficiently experienced on the off-pump procedure, should residents have been allowed to do study surgeries, should techniques have been standardized more and were the best neurocognitive tests selected.

Conclusion The study design presented allows for a balanced and fair assessment of the on-pump and off-pump CABG procedures across a diversity of clinical outcomes and resource use metrics. Its results have the potential to influence clinical cardiac surgical practice in the future.

Improved neurobehavioral functioning in emphysema patients following lung volume reduction surgery compared with medical therapy

STUDY OBJECTIVES

The goal of this study was to evaluate the neuropsychological and psychological functioning of emphysema patients following lung volume reduction surgery (LVRS) compared with patients receiving only medical therapy (MT).

DESIGN

Patients with moderate-to-severe emphysema who were enrolled in the National Emphysema Treatment Trial at two sites (National Jewish Medical and Research Center and Ohio State University) were given a neuropsychological battery at baseline, 6 to 10 weeks later (following participation in pulmonary rehabilitation), and at 6 months following randomization to either LVRS or MT treatment.

SUBJECTS AND MEASUREMENTS

Twenty patients randomized to MT, 19 patients randomized to LVRS, and 39 matched, healthy control subjects completed a battery of tests that measured cognitive functioning, depression, anxiety, and quality of life (QoL).

RESULTS

Controlling for practice, patients in the LVRS treatment arm at the 6-month follow-up demonstrated significant improvement compared with MT patients in cognitive tasks involving sequential skills and verbal memory. The LVRS patients also showed significant reductions in depression compared with the MT patients, as well as improved physical and psychosocial QoL. Correlational analysis indicated that improved immediate verbal memory in the LVRS group was related to improved QoL. No associations were found between changes in cognitive function and changes in depression, exercise performance, or pulmonary functioning.

CONCLUSION

Patients who received LVRS demonstrated improvement in specific neuropsychological functions, depression, anxiety, and QoL scores compared with patients with continued MT treatment 6 months following randomization. However, mechanisms for these neurobehavioral changes are unclear. Improved verbal memory and sequential skills following LVRS were not directly associated with depression or exercise capacity. Nonetheless, LVRS led to a strong and likely clinically significant improvement in neuropsychological functioning over and above that explained by practice effects or MT. This finding adds to the growing list of clinical benefits of LVRS over MT, and supports additional research into the underlying mechanisms of this therapeutic effect.

Clock drawing test in very mild Alzheimer's disease

OBJECTIVES

The primary objective of this study was to determine the efficacy of the clock drawing test to predict the presence of very mild Alzheimer's disease (AD). A secondary objective was to identify elements of clock drawing that were most useful in differentiating cognitively intact older adults from those with mild Alzheimer's disease.

DESIGN

Cohort based comparison of retrospective data.

SETTING

Academic research center.

PARTICIPANTS

Clock drawings from 41 outpatient cases of mild AD with Mini-Mental State Exam scores of 24 or higher and 39 age- and education-matched older adults were scored.

MEASUREMENTS

Clock drawings were blindly and independently scored by two raters using the Clock Drawing Interpretation Scale and the scoring system reported by Rouleau et al. Predictive values for positive and negative tests were calculated using cut-off scores for total score and component subscores from each of these two systems.

RESULTS

Two or more errors in the depiction of the clock hands on the Clock Drawing Interpretation Scale had a positive predictive value for AD of 100% and a negative predictive value of 51%. A score of 2 or less on the 4-point hand-placement component of the Rouleau et al. scoring system provided a positive predictive value for AD of 94% and was associated with a negative predictive value of 62%.

CONCLUSION

An individual who commits two errors or more in drawing the clock hands deserves further investigation for a possible dementia. Normal hand placement on the clock drawing test does not exclude AD. However, when prevalence rates of dementia in community-dwelling older adults are considered, these results argue that normal clock hand placement indicates that dementia is unlikely.