The CDT score of the MoCA (MCS) ranges from 0 to 3. The MoCA is a brief screening tool used to diagnose early dementia and MCI by evaluating a range of cognitive domains: memory, language, naming, visuospatial, attention, and executive functions. This study was approved by the internal review board at the College of Medicine, King Saud University, Riyadh, Saudi Arabia. Additionally, disease-related information, including the type of dialysis (peritoneal or hemodialysis), dialysis vintage, and the presence of diabetes and hypertension, was obtained. Demographic information, including age, gender, and years of education, was collected. Those with a history of brain injury, untreated metabolic disorders (e.g., thyroid disease and B12 deficiency), demyelinating disease, CNS vasculitis, or symptomatic hemorrhagic or ischemic strokes were also excluded.

We also excluded patients who had active psychiatric disorders or were taking any substances that could affect the central nervous system (CNS), such as antipsychotic medications, sedatives, or opiates. We excluded all illiterate patients, those diagnosed with a dementia disorder, or those with language or speech disorders. A total of 89 patients with ESRD, over 18 years of age, who were on dialysis for at least 90 days, were included to eliminate any possibility of uremic effects.

Data collection was conducted between November 2018 and April 2019. This is a quantitative, observational, cross-sectional study performed at the dialysis unit at King Saud University Medical City (KSUMC). The second aim of the study was to use an exploratory factor analysis to determine whether the short clock scale from the MoCA, with limited subcategories, would agree with the detailed subcomponents of two detailed clock scoring scales. Therefore, the first aim of this study was to compare CDT results measured by three scoring systems among a sample of non-dementia-diagnosed ESRD patients on dialysis and identify which patient demographic, dialysis, or comorbidity variables would significantly influence their performance. However, it is still not entirely clear how the simple method described in the MoCA corresponds with other more detailed scales, particularly in ESRD patients on dialysis. , which score the CDT on 10-point and 18-point scales, respectively. There are more detailed scales, such as those by Rouleau et al. One easy-to-use and highly familiar measure is the Montreal Cognitive Assessment (MoCA) tool, which simply grades the CDT with a score ranging from 0 to 3. The numerous scoring scales for the CDT (which have varying levels of detail) raise the question about which one is the best to use in a busy clinical setting. Considering that the CDT can be implemented by medical staff of various backgrounds, it can be used to easily screen ESRD patients for cognitive changes. Executive dysfunction is the most likely cognitive domain to be involved, while age and education are major influencers on tests of cognitive assessment in this population. Severe dementia occurs in at least a third of ESRD patients.

Patients with end-stage renal disease (ESRD) have an increased risk of developing cognitive impairment. The CDT is valuable in detecting impairments from various disorders, such as Alzheimer's disease, vascular cognitive impairment, Huntington's disease, and Parkinson's disease. The test has also been found to be complimentary to the MMSE in better detecting executive impairments. While the CDT is likely more useful in detecting dementia than mild cognitive impairment (MCI), its little influence from culture and good test-retest reliability make it a useful assessment tool that correlates with other neuropsychological tests, such as the Mini-Mental State Exam (MMSE), the dementia rating scale, the frontal assessment battery (FAB), and other measures of visuospatial and semantic functions. This test has remained popular over the years owing to its ability to assess executive function, visuospatial abilities, and short-term memory, giving it wide applicability to different disorders of cognition. Its earliest use was with patients suffering from parietal lobe lesions. The clock drawing test (CDT) is a classical test of cognition.

Moca scoring on clock hands