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

Abstract

Brief cognitive tests are widely used in neuropsychology and related areas, in order to assess and diagnose develop mental, neurological, and psychiatric conditions. The Clock Drawing Test (CDT) is also adopted as a screening tool for cognitive impairment in several conditions such as dementia, stroke, schizophrenia, mild cognitive impairment and mood disorders¹. The CDT basically consists of the drawing of dif ferent elements of a clock, including the clock face, numbers, and arrow-hands. The instructions and scoring methods vary according to each version. Influences of aging and education are also related to test performance, where children and the elderly perform worse than adults and lower education asso ciates with worse performance².Different versions of the CDT were developed. Although very similar and highly correlated³, they differ in diagnosis accuracy 4 and probably on the cognitive processes involved ABSTRACTThe Clock Drawing Test (CDT) is a cognitive screening tool used in clinical and research settings. Despite its role on the assessment of global cognitive functioning, the specific cognitive components required for test performance are still unclear. We aim to assess the role of executive functioning, global cognitive status, visuospatial abilities, and semantic knowledge on Shulman's CDT performance. Fifty-three mild cognitive impairment, 60 Alzheimer's dementia, and 57 normal elderly controls performed the CDT, the Frontal Assessment Battery, the Mini-Mental State Examination, the Stick Design Test, and a naming test (TN-LIN). An ordinal regression assessed specific neuropsychological in fluences on CDT performance. All the cognitive variables were related to the CDT, accounting for 53% of variance. The strongest association was between the CDT and executive functions, followed by global cognitive status, visuospatial processing, and semantic knowledge. Our result confirms the multidimensional nature of the test and the major role of executive functions on performance.Keywords: clock drawing test, executive functions, visuospatial abilities, semantic knowledge, dementia. Palavras-chave: teste do desenho do relógio, funções executivas, habilidades visioespaciais, conhecimento semântico, demência. RESUMO

Effects of Exercise on Cognition: The Finnish Alzheimer Disease Exercise Trial: A Randomized, Controlled Trial

“…The CDT is widely used to measure executive function. Although a strong association between the CDT and executive function has been established, global cognitive functioning, visuospatial abilities, and semantic knowledge also influence the test results …”

“…Although a strong association between the CDT and executive function has been established, global cognitive functioning, visuospatial abilities, and semantic knowledge also influence the test results. 36 More than 95% of participants in all three groups were taking AD medication, and the CG received highquality community care, which may have diluted the effect of the intervention. It has been suggested that women benefit more from exercise with respect to cognition.…”

Spontaneous Brain Activity in Type 2 Diabetics Revealed by Amplitude of Low-Frequency Fluctuations and Its Association with Diabetic Vascular Disease: A Resting-State fMRI Study

“…Conceptually, the CDT is viewed as a visuospatial task and is sensitive to right parietal pathology [48] . However, numerous studies have recently demonstrated that it also reflects frontal-lobe functions, such as executive functioning and attention [49] , [50] . Thus, in relation to the present study, poor performance on the MoCA and CDT suggest that the global cognitive decline exhibited by the T2DM patients of this cohort was multi-dimensional and may be due to damage in visuospatial- and executive-related brain regions such as the occipital and frontal regions.…”

Cross-Sectional and Longitudinal Effects of CREB1 Genotypes on Individual Differences in Memory and Executive Function: Findings from the BLSA

“…We selected six cognitive tests that have previously been shown to be sensitive to individual differences in primarily memory (Golski et al, 1998; Balthazar et al, 2008; Goh et al, 2012) or both memory and executive function (Paula et al, 2013; Shao et al, 2014) during healthy cognitive aging. These tests included the Boston Naming Test (BNT), the Benton Visual Retention Test (BVRT), California Verbal Learning Test (CVLT), the Clock Drawing Test (CLOCKs), the Category and Letter Fluency Tests.…”