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

Abstract

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.

Functional magnetic resonance imaging of the trail-making test in older adults

“…The current findings support existing literature, which identifies age-related cognitive slowing and decline in many domains including memory, spatial ability, attention, processing speed, reasoning and global cognition, irrespective of health and education levels [54][55][56]. This is in accordance with previous studies, which have revealed both performance decrements and reduced levels of brain activity to be associated with increased age in a cognitively healthy older adult population [57,58]. Importantly, the results of this study clarify the neural basis underlying specific age-related changes in task performance, since the identified brain areas are implicated in cognitive functions vital for the TMT.…”

Tablet Technology for Writing and Drawing during Functional Magnetic Resonance Imaging: A Review

“…Brain activity and CDT performance were recently studied in the same cohort of healthy elderly adults as discussed immediately above and shown in Figure 6 , using fMRI and tablet prototype 2, including performance of the standard pen-and-paper CDT for comparison [ 44 ]. For both the standard and tablet CDT, significant negative correlations were found between CDT total score (sum of R1, R2, and R3) and age (i.e., older participants performed less well than younger participants).…”

“…For both the standard and tablet CDT, significant negative correlations were found between CDT total score (sum of R1, R2, and R3) and age (i.e., older participants performed less well than younger participants). A significant positive correlation was also found between the tablet CDT scores and the paper scores [ 44 ], suggesting that the tablet had good ecological validity when applied in this context. In the fMRI analysis, the contrast of CDT vs. control (visual fixation) revealed increased activity in regions associated with visual processing, visuospatial perception, executive function, working memory, motor performance and somatosensory processing [ 45 , 46 , 47 , 48 , 49 ].…”

“…In the fMRI analysis, the contrast of CDT vs. control (visual fixation) revealed increased activity in regions associated with visual processing, visuospatial perception, executive function, working memory, motor performance and somatosensory processing [ 45 , 46 , 47 , 48 , 49 ]. The study also reported reduced CDT-related brain activity in older adults compared to younger adults, suggestive of neural changes underlying age-related reductions in CDT performance [ 44 ].…”

Object-Based Practice Effects Recover the Graphic Object Concept in Alzheimer’s Dementia

“…Aging, mild cognitive impairment and dementia is currently assessed by the Clock Drawing Test which, besides the age factors shows a strong influence of education (Mazancova et al, 2016;Talwar et al, 2019). Indeed, creating pictures needs education and has been a human endeavour since ancient times as we know for sure from cave paintings which have survived until today (Anati, 2002;Milbrath, 2010).…”