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

Diagnostic accuracy of the Brief Assessment of Impaired Cognition case-finding instrument in a general practice setting and comparison with other widely used brief cognitive tests-a cross-validation study

BACKGROUND AND PURPOSE

The aim of this study was to examine the discriminative validity of the Brief Assessment of Impaired Cognition (BASIC) case-finding instrument in a general practice (GP) setting and compare it with other widely used brief cognitive instruments.

METHODS

Patients aged ≥70 years were prospectively recruited from 14 Danish GP clinics. Participants were classified as having either normal cognition (n = 154) or cognitive impairment (n = 101) based on neuropsychological test performance, reported instrumental activities of daily living, and concern regarding memory decline. Comparisons involved the Mini-Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), the Rowland Universal Dementia Assessment Scale (RUDAS), the Mini-Cog, the 6-item Clock Drawing Test (CDT-6) and the BASIC Questionnaire (BASIC-Q).

RESULTS

BASIC demonstrated good overall classification accuracy with an area under the receiver operating characteristic curve (AUC) of 0.88 (95% confidence interval [CI] 0.84-0.92), a sensitivity of 0.72 (95% CI 0.62-0.80) and a specificity of 0.86 (95% CI 0.79-0.91). Pairwise comparisons of the AUCs of BASIC, MMSE, MoCA and RUDAS produced non-significant results, but BASIC had significantly higher classification accuracy than Mini-Cog, BASIC-Q and CDT-6. Depending on the pretest probability of cognitive impairment, the positive predictive validity of BASIC varied from 0.83 to 0.36, and the negative predictive validity from 0.97 to 0.76.

CONCLUSIONS

BASIC demonstrated good discriminative validity in a GP setting. The classification accuracy of BASIC is equivalent to more complex, time-consuming instruments, such as the MMSE, MoCA and RUDAS, and higher than very brief instruments, such as the CDT-6, Mini-Cog and BASIC-Q.

The Value of Clock Drawing Process Assessment in Screening for Mild Cognitive Impairment and Alzheimer's Dementia

Many clock drawing test (CDT) scoring systems focus on drawing results and lack drawing process assessments. This study created a CDT scoring procedure with drawing process assessment and explored its diagnostic value in screening for mild cognitive impairment (MCI) and early Alzheimer's disease (AD) from normal control (NC). We used logistic regression and receiver operating characteristic (ROC) curves to determine a new, sensitive scoring system for AD and MCI patients in a derivation cohort. The new scoring method was then compared to two common scoring systems and externally validated in a second cohort. We developed a new scoring system named CDT5, which contained one process assessment item: remember setting time without asking. Compared with two published scoring systems, CDT5 had better discriminatory power in distinguishing AD patients from NCs in derivation (area under the ROC curve [area under the curve, AUC] = .890) and validation (AUC = .867) cohorts. Three scoring systems had poor diagnostic accuracy at discriminating MCI patients from controls, with CDT5 being the most sensitive (78.57%). Adding the drawing process in CDT helps accurately detect patients with early AD, but its role in identifying patients with MCI needs to be further explored.

Discriminative capacity and construct validity of the Clock Drawing Test in Mild Cognitive Impairment and Alzheimer's disease

Objectives: The aim of this study was to analyze the psychometric and diagnostic properties of the Clock Drawing Test (CDT), scored according to the Babins, Rouleau, and Cahn scoring systems, for Mild Cognitive Impairment (MCI) and Alzheimer's disease (AD) screening, and develop corresponding cutoff scores. Additionally, we assessed the construct validity of the CDT through exploratory and confirmatory factor analysis. Methods: We developed a cross-sectional study of ambulatory MCI and AD patients, divided in two clinical groups (450 MCI and 250 mild AD patients) and a normal control group (N = 400). All participants were assessed with the CDT, Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) for convergent validity. Results: The selected scoring systems presented adequate validity and reliability values. The proposed cutoff scores showed 60 to 65% sensitivity and 58 to 62% specificity to identify MCI patients. The corresponding values for AD were 84 to 90% sensitivity and 76 to 78% specificity. Exploratory and confirmatory factor analysis revealed that the Babins scoring system had good construct validity and allowed us to propose a three-factor model for this system. Conclusions: Our results confirmed the complexity of the CDT and support it as a cognitive screening instrument particularly sensitive to AD. The use of the CDT with MCI patients should be interpreted with more caution due to the lower sensitivity and specificity for milder forms of cognitive impairment.

Age and Graphomotor Decision Making Assessed with the Digital Clock Drawing Test: The Framingham Heart Study

BACKGROUND

Digital Clock Drawing Test (dCDT) technology enables the examination of detailed neurocognitive behavior as behavior unfolds in real time; a capability that cannot be obtained using a traditional pen and paper testing format.

OBJECTIVE

Parameters obtained from the dCDT were used to investigate neurocognitive constructs related to higher-order neurocognitive decision making and information processing speed. The current research sought to determine the effect of age as related to combined motor and non-motor components of drawing, and higher-order decision making latencies.

METHODS

A large group of stroke- and dementia- free Framingham Heart Study participants were administered the dCDT to command and copy with hands set for "10 after 11". Six age groups (age range 28-98) were constructed.

RESULTS

Differences between age groups were found for total time to completion, total pen stroke count, and higher-order decision making latencies in both command and copy test conditions.

CONCLUSION

Longer age-related decision making latencies may reflect a greater need for working memory and increased self-monitoring in older subjects. These latency measures have potential to serve as neurocognitive biomarkers of Alzheimer's disease and other insidious neurodegenerative disorders.

The Reliability of Clock Drawing Test Scoring Systems Modeled on the Normative Data in Healthy Aging and Nonamnestic Mild Cognitive Impairment

The Clock Drawing Test (CDT) is a commonly used tool in clinical practice and research for cognitive screening among older adults. The main goal of the present study was to analyze the interrater reliability of three different CDT scoring systems (by Shulman et al., Babins et al., and Cohen et al.). We used a clock with a predrawn circle. The CDT was evaluated by three independent raters based on the normative data set of healthy older and very old adults and patients with nonamnestic mild cognitive impairment (naMCI; N = 438; aged 61-94). We confirmed a high interrater reliability measured by the intraclass correlation coefficients (ICCs): Shulman ICC = .809, Babins ICC = .894, and Cohen ICC = .862, all p < .001. We found that age and education levels have a significant effect on CDT performance, yet there was no influence of gender. Finally, the scoring systems differentiated between naMCI and age- and education-matched controls: Shulman’s area under the receiver operating characteristic curve (AUC) = .84, Cohen AUC = .71, all p < .001; and a slightly lower discriminative ability was shown by Babins: AUC = .65, p = .012.