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Increased light exposure consolidates sleep and strengthens circadian rhythms in severe Alzheimer's disease patients
Ancoli-Israel S, Gehrman P, Martin JL, Shochat T, Marler M, Corey-Bloom J, Levi L.. Behavioral sleep medicine, 2003-01-01
Topic: Amyloid, tau and blood-test diagnosis
Sleep in the nursing home environment is extremely fragmented, possibly in part as a result of decreased light exposure. This study examined the effect of light on sleep and circadian activity rhythms in patients with probable or possible Alzheimer's disease. Results showed that both morning and evening bright light resulted in more consolidated sleep at night, as measured with wrist actigraphy. Evening light also increased the quality of the circadian activity rhythm, as measured by a 5-parameter extended cosine model (amplitude, acrophase, nadir, slope of the curve, and relative width of the peak and trough). Increasing light exposure throughout the day and evening is likely to have the most beneficial effect on sleep and on circadian rhythms in patients with dementia. It would behoove nursing homes to consider increasing ambient light in multipurpose rooms where patients often spend much of their days.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
APA 7th
Ancoli-Israel, S., Gehrman, P., Martin, J. L., Shochat, T., Marler, M., Corey-Bloom, J., et al. (2003). Increased light exposure consolidates sleep and strengthens circadian rhythms in severe Alzheimer's disease patients. Behavioral sleep medicine. https://doi.org/10.1207/s15402010bsm0101_4
Vancouver
Ancoli-Israel S, Gehrman P, Martin JL, Shochat T, Marler M, Corey-Bloom J, et al. Increased light exposure consolidates sleep and strengthens circadian rhythms in severe Alzheimer's disease patients. Behavioral sleep medicine. 2003. doi:10.1207/s15402010bsm0101_4. PMID: 15600135.
BibTeX
@article{ancoliisrael2003-15600135,
author = {Ancoli-Israel, S. and Gehrman, P. and Martin, J. L. and Shochat, T. and Marler, M. and Corey-Bloom, J. and Levi, L.},
title = {{Increased light exposure consolidates sleep and strengthens circadian rhythms in severe Alzheimer's disease patients}},
journal = {Behavioral sleep medicine},
year = {2003},
doi = {10.1207/s15402010bsm0101_4},
pmid = {15600135},
url = {https://doi.org/10.1207/s15402010bsm0101_4}
}
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. The record names 7 authors; APA and Vancouver show the first six, BibTeX and the downloads carry all of them. Check the citation against the original before you use it.
Key findings
- Sleep in the nursing home environment is extremely fragmented, possibly in part as a result of decreased light exposure.
- Results showed that both morning and evening bright light resulted in more consolidated sleep at night, as measured with wrist actigraphy.
Why it matters
This study found that morning and evening bright light led to more consolidated night-time sleep in patients with probable or possible Alzheimer's disease, and evening light improved circadian activity rhythm quality. It suggests nursing homes consider increasing ambient light, but reports no effect on curing or preventing the disease.
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Study details
- Evidence strengthLow
How this study scored 54/100
Published in a peer-reviewed journal, and it is a randomised controlled trial. Scored zero for sample size and effect reported because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Behavioral sleep medicine) |
| Journal's citation record | 1 / 4 | Behavioral Sleep Medicine: journal h-index 84 (OpenAlex, 2026-10-29) |
| Study design | 11 / 12 | A randomised controlled trial (from PubMed type “Randomized Controlled Trial”) |
| 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 | 2003 — older than 20 years, still counted |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| 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 (pubmed indexes it as a clinical or observational study) |
| Randomised / blinded | 1 / 2 | Randomised (as stated in the record) |
| Times cited | 6 / 7 | Cited 348 times (OpenAlex, 2026-10-10) |
| Citations per year | 3 / 5 | 13.9 citations a year over 25 year(s) since 2003 |
| Impact for its field and year | 3 / 6 | Cited 4.9× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 2 / 6 | Cited by 6 other studies in this library |
| Still being cited | 2 / 4 | Cited 29 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 1 / 4 | Last-listed author Leah Levi: h-index 19 (OpenAlex, whole career) |
| Institution's track record | 0 / 3 | VA San Diego Healthcare System: institution h-index 478 (OpenAlex) |
| Multi-centre collaboration | 0 / 3 | OpenAlex lists 1 institution(s) in 1 country — scores zero (affiliation lists can be incomplete) |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 15600135) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 54 / 100 | — |
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