Clock drawing test in very mild Alzheimer's disease

Conventional clock drawing tests have low to moderate reliability and validity for detecting subtle cognitive impairments in community-dwelling older adults

Background

Early identification of subtle cognitive decline in community-dwelling older adults is critical, as mild cognitive impairment contributes to disability and can be a precursor to dementia. The clock drawing test (CDT) is a widely adopted cognitive screening measure for dementia, however, the reliability and validity of paper-and-pencil CDT scoring scales for mild cognitive impairment in community samples of older adults is less well established. We examined the reliability, sensitivity and specificity, and construct validity of two free-drawn clock drawing test scales-the Rouleau System and the Clock Drawing Interpretation Scale (CDIS)-for subtle cognitive decline in community-dwelling older adults.

Methods

We analyzed Rouleau and CDIS scores of 310 community-dwelling older adults who had MoCA scores of 20 or above. For each scale we computed Cronbach's alpha, receiver operating characteristic curves (ROC) for sensitivity and specificity using the MoCA as the index measure, and item response theory models for difficulty level.

Results

Our sample was 75% female and 85% Caucasian with a mean education of 16 years. The Rouleau scale had excellent interrater reliability (94%), poor internal consistency [0.37 (0.48)], low sensitivity (0.59) and moderate specificity (0.71) at a score of 9. The CDIS scale had good interrater reliability (88%), moderate internal consistency [0.66 (0.09)], moderate sensitivity (0.78) and low specificity (0.45) at a score of 19. In the item response models, both scales' total scores gave the most information at lower cognitive levels.

Conclusion

In our community-dwelling sample, the CDIS's psychometric properties were better in most respects than the Rouleau for use as a screening instrument. Both scales provide valuable information to clinicians screening older adults for cognitive change, but should be interpreted in the setting of a global cognitive battery and not as stand-alone instruments.

Brief Cognitive Tests for Distinguishing Clinical Alzheimer-Type Dementia From Mild Cognitive Impairment or Normal Cognition in Older Adults With Suspected Cognitive Impairment

BACKGROUND

The accuracy and harms of brief cognitive tests for identifying clinical Alzheimer-type dementia (CATD) are uncertain.

PURPOSE

To summarize evidence on accuracy and harms of brief cognitive tests for CATD in older adults with suspected cognitive impairment.

DATA SOURCES

Electronic bibliographic databases (from inception to November 2019) and systematic review bibliographies.

STUDY SELECTION

English-language, controlled observational studies in older adults that evaluated the accuracy of brief cognitive tests (standalone tests; memory, executive function, and language tests; and brief multidomain batteries) for distinguishing CATD from mild cognitive impairment (MCI) or normal cognition as defined by established diagnostic criteria. Studies with low or medium risk of bias (ROB) were analyzed.

DATA EXTRACTION

Two reviewers rated ROB. One reviewer extracted data; the other verified extraction accuracy.

DATA SYNTHESIS

Fifty-seven studies met analysis criteria. Many brief, single cognitive tests were highly sensitive and specific for distinguishing CATD from normal cognition. These included standalone tests (clock-drawing test, median sensitivity 0.79 and specificity 0.88 [8 studies]; Mini-Mental State Examination, 0.88 and 0.94 [7 studies]; Montreal Cognitive Assessment, 0.94 and 0.94 [2 studies]; and Brief Alzheimer Screen, 0.92 and 0.97 [1 study]), memory tests (list delayed recall, 0.89 and 0.94 [5 studies]), and language tests (category fluency, 0.92 and 0.89 [9 studies]). Accuracy was lower in distinguishing mild CATD from normal cognition and distinguishing CATD from MCI. No studies reported on testing harms.

LIMITATIONS

Studies were small. Few test metrics were evaluated by multiple studies. Few studies directly compared different tests, scores, cut points, or test combinations.

CONCLUSION

Many brief, single cognitive tests accurately distinguish CATD from normal cognition in older adults but are less accurate in distinguishing mild CATD from normal cognition or CATD from MCI. No studies reported on testing harms.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality. (PROSPERO: CRD42018117897).

Usefulness of the Clock Drawing Test as a Cognitive Screening Instrument for Mild Cognitive Impairment and Mild Dementia: an Evaluation Using Three Scoring Systems

Background and Purpose

Although the clock drawing test (CDT) is a widely used cognitive screening instrument, there have been inconsistent findings regarding its utility with various scoring systems in patients with mild cognitive impairment (MCI) or dementia. The present study aimed to identify whether patients with MCI or dementia exhibited impairment on the CDT using three different scoring systems, and to determine which scoring system is more useful for detecting MCI and mild dementia.

Methods

Patients with amnestic mild cognitive impairment (aMCI), vascular mild cognitive impairment (VaMCI), mild Alzheimer's disease (AD), mild vascular dementia (VaD), and cognitively normal older adults (CN) were included. All participants were administered the CDT, the Korean-Mini Mental State Examination (K-MMSE), and the Clinical Dementia Rating scale. The CDT was scored using the 3-, 5-, and 15-point scoring systems.

Results

On all three scoring systems, all patient groups demonstrated significantly lower scores than the CN. However, while there were no significant differences among patients with aMCI, VaMCI, and AD, those with VaD exhibited the lowest scores. Area under the Receiver Operating Characteristic curves revealed that the three CDT scoring systems were comparable with the K-MMSE in differentiating aMCI, VaMCI, and VaD from CN. In differentiating AD from CN, however, the CDT using the 15-point scoring system demonstrated the most comparable discriminability with K-MMSE.

Conclusions

The results demonstrated that the CDT is a useful cognitive screening tool that is comparable with the Mini-Mental State Examination, and that simple CDT scoring systems are sufficient for differentiating patients with MCI and mild dementia from CN.

Cognitive Estimation in Non-demented Parkinson's Disease

Objective

The Cognitive Estimation Test (CET) is widely used in clinical and research settings to assess the ability to produce reasonable estimates to items that individuals would not know that the exact answer (e.g., "How fast do race horses run?"). We examined the performance of non-demented Parkinson's disease (PD) patients on the CET, because previous studies reported heterogeneous results about possible cognitive estimation impairments in PD. We also examined whether PD patients improve their performance if given the chance to reconsider their initial CET responses.

Methods

Thirty non-demented idiopathic PD patients and 30 healthy controls matched in age, gender and years of education performed the two parallel forms of Italian CET. The estimation scores for initial and final responses as well as the number of times individuals changed their answers were examined. Additional neuropsychological tests, evaluating intellectual, frontal executive, speed of processing, naming and arithmetical abilities, were also administered.

Results

The PD group were not significantly poorer than healthy controls at estimating the answers to items on either CET versions. Moreover, PD patients did not significantly differ in their initial and final responses or number of response changes. Performance on the CET was significantly related to performance on a global measure of executive function, processing speed and arithmetic. However, PD patients were impaired compared to controls on the component involving mainly, but not exclusively, length-related estimations.

Conclusions

Non-demented PD patients have mild impairments in cognitive estimation ability, which may depend on the estimations they are required to provide.

Clinical Dementia Rating Orientation Score as an Excellent Predictor of the Progression to Alzheimer's Disease in Mild Cognitive Impairment

OBJECTIVE

This study aimed to examine the usefulness of each subscale score of the Clinical Dementia Rating (CDR) for predicting Alzheimer's disease (AD) dementia progression in amnestic mild cognitive impairment (MCI) elderly subjects.

METHODS

Fifty-nine elderly MCI individuals were recruited from a university dementia and memory disorder clinic. Standardized clinical and neuropsychological tests were performed both at baseline and at the time of 2 years follow-up. Logistic regression analyses were conducted to examine the ability of various clinical measures or their combinations to predict progression to AD dementia in MCI individuals.

RESULTS

MCIp individuals showed significantly higher CDR Orientation subscale and CDR sum-of-boxes (SOB) score than MCInp ones, while there were no significant differences in other CDR subscale scores between the two. MCIp individuals also showed marginally higher MMSE scores than MCInp ones. A series of logistic regression analyses demonstrated that the model including CDR Orientation subscale had better AD dementia prediction accuracy than either the model with either MMSE or CDR-SOB.

CONCLUSION

Our findings suggest that CDR Orientation subscale score, a simple and easily available clinical measure, could provide very useful information to predict AD dementia progression in amnestic MCI individuals in real clinical settings.

The Japanese version of the Rapid Dementia Screening Test is effective compared to the clock-drawing test for detecting patients with mild Alzheimer's disease

BACKGROUND

The Japanese version of the Rapid Dementia Screening Test (RDST-J) and the clock-drawing test (CDT) are both brief psychometric screening tools used to detect the severity of Alzheimer's disease. It remains unclear, however, which is more effective when screening for mild Alzheimer's disease.

METHODS

We administered the RDST-J and CDT to 250 patients with very mild to severe Alzheimer's disease and to 49 healthy volunteers. Patients with a Mini-Mental State Examination score of 12-26 had Clinical Dementia Rating (CDR) scores from 0.5 to 3. Patients were divided into four groups according to CDR score. We performed one-way factorial anova between the four groups and control subjects based on the CDT and RDST-J scores.

RESULTS

Data analysis revealed that RDST-J could distinguish patients with CDR 0.5 from the controls, but CDT could not. Furthermore, the sensitivity of a RDST-J score ≥8 was 57.1%, with a specificity of 81.0%, and the sensitivity of a RDST-J score ≥9 was 79.6%, with a specificity of 55.1% for discriminating CDR 0.5 from controls.

CONCLUSIONS

RDST-J is a more effective tool than CDT for distinguishing CDR 0.5 from controls.

Anti-arrhythmic Medication Propafenone a Potential Drug for Alzheimer's Disease Inhibiting Aggregation of Aβ: In Silico and in Vitro Studies

Alzheimer's disease (AD) is the most common form of dementia caused by the formation of Aβ aggregates. So far, no effective medicine for the treatment of AD is available. Many efforts have been made to find effective medicine to cope with AD. Curcumin is a drug candidate for AD, being a potent anti-amyloidogenic compound, but the results of clinical trials for it were either negative or inclusive. In the present study, we took advantages from accumulated knowledge about curcumin and have screened out four compounds that have chemical and structural similarity with curcumin more than 80% from all FDA-approved oral drugs. Using all-atom molecular dynamics simulation and the free energy perturbation method we showed that among predicted compounds anti-arrhythmic medication propafenone shows the best anti-amyloidogenic activity. The in vitro experiment further revealed that it can inhibit Aβ aggregation and protect cells against Aβ induced cytotoxicity to almost the same extent as curcumin. Our results suggest that propafenone may be a potent drug for the treatment of Alzheimer's disease.

"Alert and Oriented × 3?" Correlates of Mini-Cog Performance in a Post/Nondelirious Intensive Care Unit Sample

BACKGROUND

Cognitive impairment has been found to be a predictor of adverse medical outcomes, including nonadherence, recurrent medical crises resulting in early readmissions, and death.

OBJECTIVE

The Mini-Cog has been proposed for bedside/clinic cognitive testing. Its validity as a measure of central nervous system (CNS) impairment has never been tested against measures of CNS-medical history, CNS scans, selected laboratory findings, observed in-hospital nondelirious memory impairment, or collateral history from family.

METHODS

We observed Mini-Cog performance in 107 post/nondelirious medical intensive care unit patients and tested its association with age, CNS-medical history, CNS scans, selected laboratory findings, and behavioral history (in-hospital observation of memory problems and collateral history from family or significant others).

RESULTS

The overall Mini-Cog covaried with age, various measures of CNS impairment, abnormal laboratory findings, and measures of preadmission "forgetfulness" per family and by in-hospital staff observation. Unique variance in predicting overall Mini-Cog scores included age, positive CNS scan, and behavioral history. Of 91 patients found to be "alert and oriented × 3," 76% were impaired in immediate memory, short-term memory, or clock drawing.

CONCLUSIONS

The Mini-Cog appears to be a brief, yet valid, measure of CNS dysfunction that significantly enhances sensitivity of evaluation at the bedside. Failure to evaluate patients with a formal examination like the Mini-Cog appears to miss up to 76% of patients with moderate cognitive impairment.

Effects of pioglitazone or exercise in older adults with mild cognitive impairment and insulin resistance: a pilot study

AIMS

To examine the effects of pioglitazone or endurance exercise training on cognitive function in older adults with mild cognitive impairment (MCI) and insulin resistance.

METHODS

Seventy-eight adults (mean age ± SD: 65 ± 7 years) with central obesity and MCI were randomized to 6 months of endurance exercise, pioglitazone or control.

RESULTS

Sixty-six participants completed the study. Exercise training did not significantly increase peak oxygen uptake compared to control (p = 0.12). Compared to control, insulin resistance improved in the pioglitazone group (p = 0.002) but not in the exercise group (p = 0.25). There was no measureable effect of pioglitazone or exercise on cognitive performance compared to control.

CONCLUSION

In this pilot study, pioglitazone improved insulin resistance but not cognitive performance in older adults with MCI and insulin resistance.

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

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

Cerebrospinal fluid biomarkers of Alzheimer's disease

Alzheimer's disease (AD) is a fatal neurodegenerative disorder that takes about a decade to develop, making early diagnosis possible. Clinically, the diagnosis of AD is complicated, costly, and inaccurate, so it is urgent to find specific biomarkers. Due to its multifactorial nature, a panel of biomarkers for the multiple pathologies of AD, such as cerebral amyloidogenesis, neuronal dysfunction, synapse loss, oxidative stress, and inflammation, are most promising for accurate diagnosis. Highly sensitive and high-throughput proteomic techniques can be applied to develop a panel of novel biomarkers for AD. In this review, we discuss the metabolism and diagnostic performance of the well-established core candidate cerebrospinal fluid (CSF) biomarkers (β-amyloid, total tau, and hyperphosphorylated tau). Meanwhile, novel promising CSF biomarkers, especially those identified by proteomics, updated in the last five years are also extensively discussed. Furthermore, we provide perspectives on how biomarker discovery for AD is evolving.

[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.

Effect of the Tottori familial disease mutation (D7N) on the monomers and dimers of Aβ40 and Aβ42

Recent experiments have shown that the mutation Tottori (D7N) alters the toxicity, assembly and rate of fibril formation of the wild type (WT) amyloid beta (Aβ) Aβ40 and Aβ42 peptides. We used all-atom molecular dynamics simulations in explicit solvent of the monomer and dimer of both alloforms with their WT and D7N sequences. The monomer simulations starting from a random coil and totaling 3 μs show that the D7N mutation changes the fold and the network of salt bridges in both alloforms. The dimer simulations starting from the amyloid fibrillar states and totaling 4.4 μs also reveal noticeable changes in terms of secondary structure, salt bridge, and topology. Overall, this study provides physical insights into the enhanced rate of fibril formation upon D7N mutation and an atomic picture of the D7N-mediated conformational change on Aβ40 and Aβ42 peptides.

[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.

Alzheimer's disease diagnosis by detecting exogenous fluorescent signal of ligand bound to Beta amyloid in the lens of human eye: an exploratory study

We report results of a clinical exploratory human trial involving 10 participants using a combination of a fluorescent ligand and a laser scanning device, SAPPHIRE System, as an aid in the diagnosis of Probable Alzheimer's disease (AD). To the best of our knowledge, this is the first time that such a technique has been used in vivo of a human lens. The primary goal of the clinical trial, in addition to safety assessment, was to evaluate efficacy of the system. By detecting specific fluorescent signature of ligand bound beta amyloid in the supranucleus (SN) region of the human lens, a twofold differentiation factor between AD patients and Control groups is achieved. Data from our studies indicates that deeper regions of the SN provide the highest measures of ligand bound fluorescence signal from both controls and patients with AD. In addition, we present preclinical studies that were performed to investigate the binding affinity of the ligand to beta amyloid and evaluate the pharmacokinetics of the ligand in rabbit eyes. Further studies are underway involving a larger population for statistical evaluation of the method.

Cerebrovascular disease and gait and balance impairment in mild to moderate Alzheimer's disease

OBJECTIVES

Gait and movement abnormalities are traditionally considered infrequent in patients with mild/moderate Alzheimer's disease (AD). However, an increased risk of falls and gait abnormalities has been detected, even in early stages of the disease. Whether these abnormalities are associated with cerebrovascular disease, which has a high prevalence in AD, remains unclear.

DESIGN

Cross-sectional study.

SETTING

Dementia outpatient clinics.

PARTICIPANTS

24 mild/moderate AD patients with (AD+CVD) and 20 without (AD-CVD) cerebrovascular disease without a history of stroke and antipsychotic medications.

MEASUREMENTS

Physical performance, measured with the short physical performance battery [SPPB], a summary measure combining 4-meter gait speed, balance and muscle strength, and with 8-meter gait speed with a turn was compared between the two groups.

RESULTS

AD+CVD patients showed a significant higher prevalence of 4-meter gait speed slower than 0.8 m/s (37.5% vs. 5%, p-value=0.01) and balance impairment (37.5% vs. 10%, p-value=0.038), as well as a slower 8-meter gait speed with a turn (mean+SD=0.6±0.2 vs. 0.8±0.2, p-value=0.024). These associations were confirmed in multivariable models. No differences were observed for muscle strength.

CONCLUSION

In our sample, AD with cerebrovascular disease had worse gait and balance than AD without cerebrovascular disease. If confirmed, these results may have clinical implications, since cerebrovascular disease can be potentially prevented.

Role of testosterone in memory impairment of Alzheimer disease induced by Streptozotocin in male rats

BACKGROUND AND PURPOSE OF THE STUDY

Recent studies demonstrate that androgens, beyond regulating sexual behavior, exert several neuroprotective functions in the brain. The present study was designed to explore effect of testosterone in memory impairment induced by intra- cerebroventricular (icv) injection of streptozotocin (STZ) as a model of sporadic AD.

METHODS

Study was carried out on male Wistar rats. Animals were randomly divided into 11 equal groups. Experimental model of AD was induced by bilateral icv injection of STZ at the dose of 750 μg/Rat/10 μl ACSF at days 1 and 3. STZ-induced memory impairment was assessed two weeks after the last dose of STZ by using a passive avoidance task (1 mA). The interval between the placement of animals in the illuminated chamber and the entry into the dark chamber was measured as a step-through latency (STL). Castration was performed by surgical removing of testis and behavioral study of memory impairment was done after 4 weeks.

RESULTS

Results of this study showed that icv injection of STZ could induce marked (p < 0.05) memory impairment at the dose of 750 μg/Rat/dissolve10 μl CSF/bilateral/days 1 and 3. Therefore, we used this dose of STZ for induction of experimental model of AD. Memory was worsened in castrated rats (P < 0.05) when compared with normal and sham-operated animals. Testosterone replacement therapy (1 mg/kg, sc, for 6 days) in 4 week castrated rats restored memory up to the level of control groups. Testosterone had not any significant effect on memory impairments of non-castrated rats.

MAJOR CONCLUSION

According to the obtained results it can be concluded that testosterone improves cognitive and memory impairment of AD. We suggest that testosterone replacement therapy may have beneficial effect in ameliorating memory impairments of senile patients suffering from AD. Further clinical studies should be carried out to prove possible useful effect of testosterone as an adjuvant therapy in AD.

Curcumin binds to Aβ1-40 peptides and fibrils stronger than ibuprofen and naproxen

Binding of curcumin, naproxen, and ibuprofen to Aβ1-40 peptide and its fibrils is studied by docking method and all-atom molecular dynamics simulations. The Gromos96 43a1 force field and simple point charge model of water have been used for molecular dynamics simulations. It is shown that if the receptor is a monomer then naproxen and ibuprofen are bound to the same place that is different from the binding position of curcumin. However all of three ligands have the same binding pocket in fibrillar structures. The binding mechanism is studied in detail showing that the van der Waals interaction between ligand and receptor dominates over the electrostatic interaction. The binding free energies obtained by the molecular mechanic-Poisson-Boltzmann surface area method indicate that curcumin displays higher binding affinity than nonsteroidal anti-inflammatory drugs. Our results are in good agreement with the experiments.

Clock drawing test - screening utility for mild cognitive impairment according to different scoring systems: results of the Leipzig Longitudinal Study of the Aged (LEILA 75+)

BACKGROUND

There is a strong demand for screening instruments for mild cognitive impairment (MCI), as a pre-stage of dementia. The clock drawing test (CDT) is widely used to screen for dementia, but the utility in screening for MCI remains uncertain. In particular, it is still questionable which scoring system is the best in order to screen for MCI. We therefore aimed to compare the utility of different CDT scoring systems for screening for MCI.

METHODS

In a sample of 428 subjects of the Leipzig Longitudinal Study of the Aged (LEILA 75+) study, CDT scores of different scoring systems were compared between subjects with and without MCI. Comparison of receiver operating characteristic (ROC; area under the curve, sensitivity, specificity) was performed and inter-rater reliability was calculated.

RESULTS

The CDT scores differed significantly between MCI and non-MCI subjects according to all scoring systems applied. However, ROC of the CDT scores was not adequate.

CONCLUSIONS

None of the present CDT scoring systems has sufficient utility to screen reliably for MCI. The clinical value of the CDT could be improved by using semi-quantitative scoring, having a wider score range and focusing on specific details of the clock (e.g. the hands and numbers).

Technical aspects of amyloid imaging for Alzheimer's disease

[¹¹C]Pittsburgh Compound B positron emission tomography has now been extensively used to evaluate the amyloid load in different types of dementia and has become a powerful research tool in the field of neurodegenerative diseases. In the present short review we discuss the properties of amyloid imaging agent [¹¹C]Pittsburgh Compound B, the different modalities of molecular imaging, image processing and data analysis, and newer amyloid imaging agents.

Longitudinal assessment of cognitive function by clock drawing in older adults

AIMS

To test the hypotheses that performance on a clock-drawing task (CDT) diminishes over time and that poor performance is associated with development of dementia and reduced survival.

METHODS

Participants in the population-based Leisure World Cohort Study were asked to complete a CDT in follow-up questionnaires mailed in 1992 and 1998. Dementia status was determined using in-person evaluations, follow-up questionnaires, hospital data, and death certificates.

RESULTS

Of the 4,842 cohort members (mean age 80 years) who completed the CDT in 1992, 1,521 also completed it in 1998. Although performance in the CDT diminished over time in only a proportion of the cohort, the mean total score and the percentage of subjects with correctly drawn clocks decreased with each successive 5-year age group (p = 0.0001) and over time. Mean scores were lower in non-demented subjects later identified as demented compared with those who remained free of dementia. A low CDT score in 1992 was associated with a 28% increased risk of dementia and 13% reduced survival.

CONCLUSION

A CDT may help predict cognitive decline and future disability in the elderly. Identification of high-risk individuals using a CDT may lead to earlier diagnosis and treatment and improved patient management.

Independent association between preoperative cognitive status and discharge location after cardiac surgery

BACKGROUND

Among cardiac surgery patients, those with impaired cognitive status before surgery may have longer postoperative stays than do patients with normal status and may require additional care upon discharge.

OBJECTIVES

To determine if preoperative scores on a screening measure for cognitive status (the Clock-in-the-Box), were associated with postoperative length of stay and discharge to a location other than home in patients who had cardiac surgery.

METHODS

A total of 181 consecutive patients scheduled for cardiac surgery at a single site were administered the Clock-in-the-Box as part of the preoperative evaluation. Scores on the Clock-in-the-Box tool, demographic and operative information, postoperative length of stay, and discharge location were collected retrospectively from medical records.

RESULTS

The mean age of the patients was 68.1 years (SD, 0.7), and 99% were men. Mean postoperative length of stay was 10.5 days (SD, 8.2), and 35 patients (19%) were discharged to a facility. Scores on the Clock-in-the-Box assessment were not associated with postoperative length of stay. Increasing age, living alone before surgery, and duration of cardiopulmonary bypass were associated with discharge to a facility and were used as covariates in adjusted analyses. After adjustment, better preoperative cognitive status reduced the risk of being discharged to a facility (adjusted relative risk, 0.93; 95% confidence interval, 0.89-0.98) after cardiac surgery.

CONCLUSIONS

Cognitive screening before cardiac surgery can identify patients with impaired cognitive status who are less likely than patients with normal cognitive status to return home after cardiac surgery.

Can an 18-point clock-drawing scoring system predict dementia in elderly individuals with mild cognitive impairment?

The purpose of this study was to develop a clock-drawing scoring system better suited to detecting possible early markers of dementia in individuals with mild cognitive impairment (MCI). We modified the scoring system of Freedman et al. (1994), in which the major components are integrity of the circle, placement and size of the hands, and placement and sequence of the numbers. We rescored the clock-drawing test using a novel 18-point scoring system, which emphasizes hand elements-number of hands, direction indicated, and size differences. We retrospectively assessed 123 individuals (ages 58-88 years) selected from the Memory Clinic at the Jewish General Hospital in Montreal. These consisted of 21 normal elderly individuals (NORM group), 41 participants with mild cognitive impairment who did not develop dementia on follow-up visits (MCI-NP), 41 participants with mild cognitive impairment who became demented after a 48-month follow-up (MCI-D), and 20 participants diagnosed with Alzheimer's disease (AD). On the 18-point system, the MCI-NP and the MCI-D did not show any difference on overall total score (p = .166), However, using Pearson chi-squares to examine the within-categories effects comparing the mildly cognitively impaired groups (MCI-NP and MCI-D), there were three significant hand items that appear to be possible early markers of progression to dementia. The clock has two hands (p = .043), hour hand is towards correct number (p = .023), and size difference of the hands is respected (p = .004), all showed significant differences between progressors and nonprogressors. The 18-point clock-drawing scoring system may have advantages in better indicating MCI individuals more likely to progress to dementia.

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.

Beta-secretase: structure, function, and evolution

The most popular current hypothesis is that Alzheimer's disease (AD) is caused by aggregates of the amyloid peptide (Abeta), which is generated by cleavage of the Abeta protein precursor (APP) by beta-secretase (BACE-1) followed by gamma-secretase. BACE-1 cleavage is limiting for the production of Abeta, making it a particularly good drug target for the generation of inhibitors that lower Abeta. A landmark discovery in AD was the identification of BACE-1 (a.k.a. Memapsin-2) as a novel class of type I transmembrane aspartic protease. Although BACE-2, a homologue of BACE-1, was quickly identified, follow up studies using knockout mice demonstrated that BACE-1 was necessary and sufficient for most neuronal Abeta generation. Despite the importance of BACE-1 as a drug target, development has been slow due to the incomplete understanding of its function and regulation and the difficulties in developing a brain penetrant drug that can specifically block its large catalytic pocket. This review summarizes the biological properties of BACE-1 and attempts to use phylogenetic perspectives to understand its function. The article also addresses the challenges in discovering a selective drug-like molecule targeting novel mechanisms of BACE-1 regulation.

Sensitivity and specificity of the clock drawing test, incorporating Rouleau scoring system, as a screening instrument for questionable and mild dementia: Scale development

OBJECTIVE

The objective of this study was to validate the Rouleau scoring system for the Clock Drawing Test (CDT) in northern Taiwan, a non-English speaking area, to increase its generalization by detecting subjects with questionable dementia (QD) from normal controls (NC) and subjects with mild dementia (AD). The system consists of two parts: a 10-point scoring and error types. A cross-sectional design was used. One hundred and sixteen subjects were recruited from a memory disorder clinic (n=40 NC; n=34 QD; n=42 AD). Reliability and validity were estimated, the predictive accuracy was calculated using the receiver operating characteristic (ROC) curve analysis, and the error types were counted.

RESULTS

The results indicated that most of the error types committed were conceptual deficiencies and graphic difficulties; more errors were found in the command condition (CDT-command) than in the copy condition (CDT-copy); 15% of the subjects drew smaller clock circles in CDT-command, which did not relate to any other errors. No small clock was found in CDT-copy because a pre-dawn circle was provided. The inter-rater reliability of the Rouleau scoring system was .87 and .83 for the CDT-command and -copy, respectively, while the discriminate accuracy of the scoring system was relatively low in detecting QD vs. NC, QD vs. AD, but somewhat better in distinguishing AD vs. NC groups for the areas under the ROC curves was equal to .72 for the CDT-command, and .73 for the CDT-copy. Visuospatial construction and executive functioning explained the largest score variance of the CDT in both conditions, while depressive symptoms were not significantly associated with the CDT performance.

CONCLUSION

The CDT using the Rouleau scoring system has been validated in mild AD subjects in Taiwan; however, to screen for QD sufferers, alternative scoring systems emphasizing hands or combining CDT with different neuropsychological tests such as the Clinical Abilities Screening Instrument are recommended.

In my car the brake is on the right: pedal errors among older drivers

PURPOSE

To assess to what extent specific cognitive functions contribute to pedal errors among older drivers.

METHODS

180 subjects aged 65 and older completed a 30 min driving evaluation on a simulator as well as three cognitive tests, the Mini-Mental State Exam (MMSE), the Clock Drawing Test, and Trailmaking Part A and B. Analyses based on logistic regressions were performed using age, gender, MMSE, Trailmaking Part A and B, and Clock Drawing Test as independent variables.

RESULTS

Results indicate that Clock Drawing is the best predictor of pedal errors (odds ratio=10.04, p<.0001, 95% CI: 3.80, 26.63) followed by age > or =84 (odds ratio 6.10, p<.05, 95% CI: 1.77, 21.03). In contrast, Trailmaking Part A and B, gender, and the MMSE were not significantly related to pedal errors.

CONCLUSION

Executive dysfunction may be an important contributor to pedal errors and thus unsafe driving. Practitioners may wish to consider measures of executive function when evaluating patients for driving safety.

Error specific restrictions for older drivers: promoting continued independence and public safety

OBJECTIVES

To describe a population of older drivers with driving restrictions, their most common restrictions, and to compare restricted drivers to their safe and unsafe counterparts. Safe drivers are those who do not commit hazardous errors or traffic violations. Unsafe drivers are those who commit hazardous errors and/or traffic violations that place them in hazardous situations. Restricted drivers are those who have committed traffic or rule violations only under certain driving conditions.

DESIGN

A retrospective, cross-sectional study with mixed methodology.

SETTING

A clinical driving evaluation program within an academic geriatrics department.

PARTICIPANTS

Drivers age 60+ (N=108) referred for clinical driving evaluation and who consented to allow their data to be used for research purposes.

INTERVENTION

Drivers performing at an intermediate level driving fitness were issued error specific driving restrictions.

MEASUREMENT

Driving evaluation included clock drawing test (CDT), mini-mental status exam (MMSE), Trailmaking, geriatric depression scale (GDS), and simulated driving.

RESULTS

The three most common restrictions were limited driving distance (N=8), limited driving time (N=8), and daytime only driving (N=8). Safe, restricted, and unsafe drivers significantly differed on MMSE (F[2,104]=10.75, p<0.001), Trailmaking Part B (F[2,76]=9.96, p<0.001), CDT (F[2,98]=29.88, p<0.001), and total number of hazardous errors (F[2,97]=39.06, p<0.001). Tukey's test indicated safe and restricted drivers scored significantly better than unsafe drivers on MMSE (safe: p<0.001; restricted: p=0.008), CDT (p<0.001), and hazardous errors (p<0.001). Restricted and unsafe drivers required significantly more time to complete Trailmaking B than safe drivers (p=0.004).

CONCLUSION

Preliminary data indicate restricted drivers perform more like safe than unsafe drivers. Driving simulation is instrumental in discerning error specific limitations and categorizing patients as conditionally safe. This clinical evaluation pilots an effective alternative to premature driving cessation.

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

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

Incremental geriatric assessment

Older adults value (1) independence and the ability to make their own decisions, (2) mobility (the ability to travel outside or simply inside the home), (3) family and friends and the time spent with those persons who are important to them, (4) ethnicity, religion, and spirituality, and (5) home, wherever that might be. The importance of recognizing each person's individuality cannot be overemphasized. The method of incremental assessment presented in this article and summarized in Box 9 is intended to provide the office-based clinician with sufficient information to make decisions regarding the preventive, therapeutic, rehabilitative, and supportive goals of care. IADL and nutritional triggers are used to identify early signs of dysfunction in the home environment. The strengths and weaknesses of cognitive, physical, psychosocial, and spiritual aspects of function are examined in an incremental manner. Health care providers determine whether there is a match between the person's functional capabilities, the available support network, and the home environment. The approach prompts appropriate use of services needed by older adults who are either at risk for becoming, or already are, chronically ill, disabled, and functionally dependent. Use of validated assessment tools provides structure for the assessment process, helps assure consistency, and provides a mechanism for periodic re-evaluation. The assessment approaches also foster a common language for the health care team and consist of measurable parameters that can be used to monitor outcomes. The clinician should be flexible and realize that the assessment or the tools may need to be modified depending on the circumstances.

Therapeutic potential of neurotrophic factors in neurodegenerative diseases

There is a vast amount of evidence indicating that neurotrophic factors play a major role in the development, maintenance, and survival of neurons and neuron-supporting cells such as glia and oligodendrocytes. In addition, it is well known that alterations in levels of neurotrophic factors or their receptors can lead to neuronal death and contribute to the pathogenesis of neurodegenerative diseases such as Parkinson disease, Alzheimer disease, Huntington disease, amyotrophic lateral sclerosis, and also aging. Although various treatments alleviate the symptoms of neurodegenerative diseases, none of them prevent or halt the neurodegenerative process. The high potency of neurotrophic factors, as shown by many experimental studies, makes them a rational candidate co-therapeutic agent in neurodegenerative disease. However, in practice, their clinical use is limited because of difficulties in protein delivery and pharmacokinetics in the central nervous system. To overcome these disadvantages and to facilitate the development of drugs with improved pharmacotherapeutic profiles, research is underway on neurotrophic factors and their receptors, and the molecular mechanisms by which they work, together with the development of new technologies for their delivery into the brain.

Drawing clocks and driving cars

OBJECTIVE

The purpose of the study was to determine whether a new method of scoring the Clock Drawing Test (CDT) is a reliable and valid method for identifying older adults with declining driving competence.

DESIGN

Prospective cohort study.

SETTING

An outpatient driving evaluation clinic.

PARTICIPANTS

One hundred nineteen community-dwelling, active drivers with a valid driver's license, aged 60 and older referred for driving evaluation.

MAIN OUTCOME MEASURES

The CDT and a driving test using a STISIM Drive simulator.

RESULTS

The CDT showed a high level of accuracy in predicting driving simulation outcome (area under the receiver-operator curve, 0.90; 95% confidence interval, 0.82 to 0.95). CDT scoring scales were comparable and all correlations between CDT scores and driving performance were negative, implying that as the CDT score decreases, the number of errors increases. Interrater reliability of CDT scores was 0.95. Subjects scoring less than 5 out of 7 points on the CDT made significantly more driving errors, hazardous and in total (P<.001).

CONCLUSIONS

The CDT can help establish problems with executive function and indicate the need for a formal driving evaluation. Our CDT scoring scale is a reliable, valid, and time-effective screening tool for identifying elderly drivers in need of further evaluation.

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

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

Validation of a short cognitive tool for the screening of dementia in elderly people with low educational level

AIM

To validate the 'Prueba Cognitiva de Leganés' (PCL) as a screening tool for cognitive impairment in elderly people with little formal education.

METHODS

The PCL is a simple cognitive test with 32 items that includes two scores of orientation and memory and a global score of 0-32 points. It was applied to a population sample of 527 elderly people over 70 with low educational level, who were independently diagnosed by consensus between two neurologists as having normal cognitive function, age associated cognitive decline (AACD, IPA-OMS criteria) or dementia (DSM-IV criteria). Individuals with severe visual or hearing defects and those who rejected the exam were excluded from the study. The PCL was validated in a sample of 375 individuals: 300 normal, 42 with AACD and 33 with dementia. The sensitivity, specificity, accuracy and likelihood ratios, as well as the ROC curves for dementia and for AACD-dementia, were calculated. The confounding effect of sociodemographic variables was assessed by logistic regression analysis and convergent validity by partial correlations of the PCL with other cognitive tests. Inter-rater reliability was evaluated with the intraclass correlation coefficient.

RESULTS

The PCL identified dementia (cut-off < or =22) and AACD-dementia (cut-off < or =26), with the following diagnostic parameters, respectively: sensitivity 93.9%-80%, specificity 94.7%-84.3%, positive likelihood ratio 17.8-5.1, negative likelihood ratio 0.06-0.24, and accuracy 94.6%-83.4%. The areas under the ROC curve were 0.985 (95% Confidence Intervals (CI) 0.967-0.995) and 0.904 (95% CI: 0.870-0.932) respectively. The intraclass correlation coefficient was 0.79 (0.74-0.83).

CONCLUSION

The PCL is a simple instrument, which is both valid and reliable, for the screening of dementia in population samples of individuals with low educational level. This instrument could be useful in primary health care.