Ancoli‐Israel 2003.

Study characteristics
Methods	Study design: RCT Follow‐up: day 11–15
Participants	Country: USA Setting: unclear number of long‐term care facilities Inclusion criteria: probably or possible Alzheimer's disease Exclusion criteria: recent or severe stroke primary psychiatric disorder which predated the suspected onset of dementia Number of participants completing the study: 92 (IG1 30, IG2 31, CG3 31) Baseline characteristics: not reported Group differences: no group differences
Interventions	Intervention 1: morning bright light: given from 9:30 a.m. to 11:30 a.m., bright light resulted in an exposure of 2500 lux for 10 days Intervention 2: evening bright light: given from 5:30 p.m. to 7:30 p.m., bright light resulted in an exposure of 2500 lux for 10 days Intervention 3: morning dim red light: given from 9:30 a.m. to 11:30 a.m., dim red light resulted in an exposure of < 300 lux for 10 days Intervention 4: residents were accompanied by staff members for 6 hours during the day for 10 days, ensuring that residents would not fall to sleep
Outcomes	Wake after sleep onset (actigraphy) Total sleep time in hours (actigraphy) Percentage wake (actigraphy) Percentage sleep (actigraphy)
Funding	Sponsorship source: National Institute on Aging National Cancer Institute Department of Veterans Affairs Mental Illness Research, Education, and Clinical Center Research Service of the Veterans Affairs San Diego Healthcare System
Notes	In a personal communication (email 17 July 2022) the first author Dr Ancoli‐Israel confirmed that the 2 publications refer to the same study.
Risk of bias
Bias	Authors' judgement	Support for judgement
Sequence generation	Low risk	Quote: "Block‐stratified randomization using preassignment by order of entry was used. Stratification was by gender and by quartiles of the categorical SSS distribution. This information was used to assign patients randomly to one of four treatments: evening bright light, morning bright light, evening dim red light, and daytime sleep restriction (DSR)."
Allocation concealment	Unclear risk	Participants were randomly assigned to 1 of 3 treatment groups: morning bright light (30 participants), morning dim red light (31 participants), or evening bright light (31 participants), by block stratified randomisation using preassignment by order of entry within strata. Participants were stratified by type of agitation (i.e. agitated primarily in the morning, agitated primarily in the evening, or agitated all day based on nurses' ratings).
Blinding of participants and personnel All outcomes	Unclear risk	Unknown.
Blinding of participants and personnel Subjective sleep quality (carer ratings)	Unclear risk	Unknown.
Blinding of participants and personnel Objective sleep measures	Unclear risk	Unknown.
Blinding of outcome assessors Objective outcome measures	Low risk	Although nursing staff and research staff could not be kept blind to light treatment condition, all were told that both white and red light conditions were expected to show improvement and the study was examining which light colour would be better.
Blinding of outcome assessors Subjective sleep quality (carer ratings)	Unclear risk	No information available.
Incomplete outcome data All outcomes	Unclear risk	Of the 92 participants, 8 (8.7%) refused to wear the Actillume. 1 initially agreed, but then took the Actillume off and lost it. 9.5% of data were loss due to either human or device error. Overall, of 368 data files, 84% were usable. For 12 participants, 1 of the 4 files (baseline, treatment days 1–5, treatment days 6–10, or post‐treatment follow‐up) was missing; therefore, data for those 12 participants could not be included in all analyses. Complete analyses were performed on the remaining 72 participants. Judgement comment: 72/92 participants not assessed with no information about allocation.
Selective outcome reporting	Unclear risk	Protocol not identified.
Other sources of bias	Low risk	None.