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Related Experiment Videos

CLOX: an executive clock drawing task

D R Royall1, J A Cordes, M Polk

  • 1Department of Psychiatry, University of Texas, Health Science Center at San Antonio, 78284-7792, USA. royall@uthscsa.edu

Journal of Neurology, Neurosurgery, and Psychiatry
|May 23, 1998
PubMed
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The clock drawing task (CLOX) effectively identifies executive dysfunction in elderly individuals, distinguishing it from constructional difficulties. This reliable tool aids in diagnosing dementia subtypes.

Area of Science:

  • Neuroscience
  • Gerontology
  • Psychometrics

Background:

  • Executive dysfunction is a key feature of cognitive decline in aging and dementia.
  • Differentiating executive impairment from constructional apraxia is crucial for accurate diagnosis.
  • Existing cognitive assessments may not fully capture executive control deficits.

Purpose of the Study:

  • To introduce and validate the Clock Drawing Task (CLOX) as a tool for assessing executive function.
  • To determine if CLOX can differentiate executive impairment from constructional failure.
  • To evaluate CLOX's reliability and correlation with other cognitive measures.

Main Methods:

  • The CLOX, comprising unprompted (CLOX1) and copied (CLOX2) tasks, was administered to 90 elderly subjects (45 healthy, 45 with Alzheimer's disease) and 62 young controls.

Related Experiment Videos

  • Subjects also completed the EXIT25 (executive test) and Mini-Mental State Examination (MMSE).
  • Inter-rater reliability was assessed, and CLOX subscores were correlated with cognitive severity and diagnostic groups.

    • Main Results:

    • CLOX subscores showed strong correlations with cognitive severity (CLOX1 with EXIT25, CLOX2 with MMSE).
    • The EXIT25 significantly predicted CLOX1 variance, while MMSE predicted CLOX2 variance.
    • CLOX subscales accurately classified Alzheimer's disease patients versus controls (83.1%) and differentiated dementia subgroups (91.9%).

    Conclusions:

    • The CLOX is a reliable, easy-to-administer measure with high inter-rater reliability.
    • CLOX scores are strongly associated with established cognitive test results.
    • The CLOX demonstrates potential for discriminating between clinical dementia subtypes based on failure patterns.