Table 3: Characteristics of studies.
Author/ Year |
Country |
Study Design, Setting, Period |
Population (Sample) |
Intervention Characteristics |
Outcome Measured |
Outcomes and Findings |
Cremascoli, et al. [30] |
Italy |
Randomised placebo- controlled, single-blind trial, over a 3-month period at the Unit of Sleep Medicine of IRCCS Mondino Foundation |
Patients with mild/ moderate AD Total sample: n = 13 Intervention group: n = 8 Control group: n = 5 Mean age: 73 4 females, 9 males |
Intervention group: Blue‐enriched light (Luminette glasses), 10,000 lux, 20 min once a day, every day, 4 weeks
Control Group: Use of the same Luminette device set at a fluorescence of 50 lux, 20 min once a day, everyday, 4 weeks
Light delivery was planned according to the individual circadian phase of each participants. |
Sleep-wake rhythms, sleep quality, mood, and cognition
Subjective sleep measurement: PSQI, ESS
Objective sleep measurement: Actigraphy watch, 24h wake-sleep diaries
Cognition: MMSE
Mood: NPI, Beck depression inventory |
The treatment induced an objective circadian phase shift consistent with the melatonin phase response curve to light exposure, led to a shortening of the phase angle DLMO-falling asleep time, and was associated with an improvement in subjective sleep quality and cognitive performance. |
Figueiro, et al. [31] |
USA |
Randomised placebo- controlled, crossover design clinical trial
8 long-term care facilities for two 4- week period (separated by a 4- week washout) |
Patients with moderate to late-stage AD and related dementia (ADRD)
Total sample: n = 46 Intervention group: n = 25 Control group: n = 21 Mean age: 85.1 30 females, 16 males |
Intervention group: High circadian stimulus, Full spectrum white light, 550-700 lux Bright light (light box, light panels) 24 h (tailored lighting), everyday, 14 weeks
Control group: Low circadian stimulus, 110-200 lux dim light, 24h, everyday, 14 weeks
Timers controlled all lights for both interventions, activating the lights according to the individual participants habitual wake times |
Sleep quality, depression, agitation, quality of life
Subjective sleep measurement: PSQI
Objective sleep measurement: Actigraphy
Mood and behaviour: CMAI, CSSD |
The active intervention significantly improved Pittsburgh Sleep Quality Index scores compared to the active baseline and control intervention. The active intervention also resulted in significantly greater active versus control differences in intradaily variability. As for secondary outcomes, the active intervention resulted in significant improvements in Cornell Scale for Depression in Dementia scores and significantly greater active versus control differences in Cohen- Mansfield Agitation Inventory scores |
Hjetland, et al. [32] |
Norway |
24-week cluster randomised Placebo- controlled trial |
Patients with severe dementia Total sample: n = 69 Intervention Group: n = 33 Control group: n =36 Mean age: 84 years females, 22 males |
Intervention Group: ambient light of 1000 lx and 6000 K from 10:00 to 15:00, with gradually increasing and decreasing light levels prior to and following this interval, using ceiling mounted light-fixtures and light emitting diode technology
Control Group: The placebo condition had continuous standard light levels (150-300 lx, ~ 3000 K) |
Sleep outcomes
Subjective Sleep: SDI
Objective Sleep: actigraphy |
Sleep as measured by the SDI was significantly improved in the intervention group compared to the control group from baseline to week 16 and from baseline to week 24. There was no significant effects in terms of actigraphically measured sleep.
There was no effect according to the SDI at week 8 compared to the control group, the intervention group fared better from baseline to week 16 and from baseline to week 24, as measured by the proxy-rated SDI. Overall, proxy-rated sleep improved among nursing home patients with dementia following 16 and 24 weeks of BLT. These improvements were not corroborated by actigraphy recordings |
Kheradmand, et al. [33] |
Iran |
Double-blinded randomized placebo- controlled study |
Patients with moderate to severe AD Total sample: n = 32 Intervention group: 16 Control group: 16 Mean age: 77.13 females, 15 men |
Intervention group: LLT for 10 minutes and 6 sessions (3 times a week for 2 weeks). The LLLT system includes a helmet and a control device. Lasers operated in pulse mode with a frequency of 75 Hz. In one session, the cumulative dose for each laser emitter and all 24 lasers inside the helmet were 12 and 288 J
Control group: Sham therapy for 10 minutes and 6 sessions (switched off laser) |
Cognition: MMSE |
The results showed considerable progress in the cognitive function of the patients undergoing LLLT based on the MMSE results 2 weeks after initiation of treatment. In contrast, the MMSE scores worsened in the sham group. In addition, after 6 weeks, the positive effect of LLLT on the cognitive function of the patients was also observed. |
Kim, et al. [34] |
South Korea |
Single-blind RCT |
Patients with mild and moderate AD Total sample: n = 25 Intervention group: n = 14 (77.36 ± 5.79 years; M: F = 2:12) Control group: n = 11 (78.55 ± 7.71 years; M:F = 5:6) |
Intervention Group: Blue-enriched white light: 30 lux; Blue attenuating light (10 lx), 1 times/day, 7 d/week, 60 min, 2 weeks
Control group: Same, blue-enriched white light + blue- attenuating sunglasses 1 times/day, 7 d/week, 60 min, 2 weeks.
Both groups Sat about 60 cm away from a small LED light box for 1h each morning for 2 weeks. |
Sleep, cognition, depression, mood, and behavior
Sleep: PSQI, actigraphy, sleep diary
Mood and behaviour: KNPI-Qs, CSDD-K , VAS
Cognition: MMSE- KC |
Blue‐enriched LT had a significantly better effect on the Pittsburgh Sleep Quality Index at T2 compared to blue‐ attenuated LT, and a trend of better effectiveness on total sleep time at T2. There was a significant increase in Mini‐Mental State Examination score at T2 after blue‐enriched LT than that at T0. Our findings suggest that morning blue‐enriched LT has a benefit in improving sleep and cognitive function in AD patients. |
Kolberg, et al. [25] |
Bergen, Norway |
24-week cluster randomised controlled trial |
Patients with severe dementia
Total Sample: n = 61 Intervention Group = 31 Control group = 30 Mean age: 84 44 females, 20 males |
Intervention Group: ceiling-mounted LED panels providing varying illuminance and correlated color temperature throughout the day, with a peak of 1000 lx, 6000 K between 10 a.m. and 3 p.m
Control Group: lights bulbs were changed but still delivered standard indoor illumination (~150-300 lx, 3000 at eye level in the center of the room). |
Rest-activity rhythms measured by actigraphs |
After 16 weeks, the acrophase was advanced from baseline in the intervention group compared to the control group. There was no significant difference between the groups on any other rest-activity measures. When comparing parametric and non-parametric indicators of rest- activity rhythms, 25 out of 35 comparisons were significantly correlated. The present results indicate that ambient bright light treatment did not improve rest-activity rhythms for people with dementia. |