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CLOX: an executive clock drawing task
Royall DR, Cordes JA, Polk M.. Journal of neurology, neurosurgery, and psychiatry, 1998-05-01
Topic: Risk, prevention and care in population studies
Objective To describe a clock drawing task (CLOX) designed to elicit executive impairment and discriminate it from non-executive constructional failure. Subjects 90 elderly subjects were studied (45 elderly and well persons from the independent living apartments of a continuing care retirement community and 45 patients with probable Alzheimer's disease). The clock drawing performance of elderly patients was compared with that of 62 young adult controls.
Key findings
- Subjects 90 elderly subjects were studied (45 elderly and well persons from the independent living apartments of a continuing care retirement community and 45 patients with probable Alzheimer's disease).
- The clock drawing performance of elderly patients was compared with that of 62 young adult controls.
- Methods Subjects received the CLOX, an executive test (EXIT25), and the mini mental state examination (MMSE).
- The CLOX is divided into an unprompted task that is sensitive to executive control (CLOX1) and a copied version that is not (CLOX2).
Why it matters
This study describes a clock drawing task designed to detect executive impairment and distinguish it from non-executive constructional failure. It is a test-development study comparing elderly well persons, patients with probable Alzheimer's disease, and young adult controls, not a treatment study.
Study details
- Participants45
- Evidence strengthLow
How this study scored 51/100
Published in a peer-reviewed journal. Scored zero for study design, effect reported and randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Journal of neurology, neurosurgery, and psychiatry) |
| Journal's citation record | 3 / 4 | Journal of Neurology Neurosurgery & Psychiatry: journal h-index 336 (OpenAlex, 2026-10-29) |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 1998 — older than 20 years, still counted |
| Sample size | 1 / 4 | 45 participants |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 6 / 7 | Cited 846 times (OpenAlex, 2026-10-10) |
| Citations per year | 4 / 5 | 28.2 citations a year over 30 year(s) since 1998 |
| Impact for its field and year | 3 / 6 | Cited 4.2× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 3 / 6 | Cited by 23 other studies in this library |
| Still being cited | 3 / 4 | Cited 67 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 2 / 4 | Last-listed author Marsha J. Polk: h-index 28 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | The University of Texas at San Antonio Health Science Center: institution h-index 883 (OpenAlex) |
| Multi-centre collaboration | 1 / 3 | OpenAlex lists 2 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 9598672) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 51 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
- DOI: 10.1136/jnnp.64.5.588
- PubMed: 9598672
- Original source →
- Free full text: Journal of Neurology Neurosurgery & Psychiatry →
Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. Check the citation against the original before you use it.
APA 7th
Royall, D. R., Cordes, J. A., & Polk, M. (1998). CLOX: an executive clock drawing task. Journal of neurology, neurosurgery, and psychiatry. https://doi.org/10.1136/jnnp.64.5.588
Vancouver
Royall DR, Cordes JA, Polk M. CLOX: an executive clock drawing task. Journal of neurology, neurosurgery, and psychiatry. 1998. doi:10.1136/jnnp.64.5.588. PMID: 9598672.
BibTeX
@article{royall1998-9598672,
author = {Royall, D. R. and Cordes, J. A. and Polk, M.},
title = {{CLOX: an executive clock drawing task}},
journal = {Journal of neurology, neurosurgery, and psychiatry},
year = {1998},
doi = {10.1136/jnnp.64.5.588},
pmid = {9598672},
url = {https://doi.org/10.1136/jnnp.64.5.588}
}
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