Table 2.
Effect of light in AD patients.
| First author, year, reference | Participants | Head-to-light distance | Intervention | Duration and frequency | Assessment tools | Outcome |
| Sonia Ancoli-Israel, 2010[59] | 92 probable or possible Alzheimer's disease patients | 1.0 m | 2500 lux bright light or <300 lux red light | 9:30 am to 11:30 am and 5:30 pm to 7:30 pm for 10 days | The Actillume recorder | Both morning and evening bright light resulted in more consolidated sleep at night |
| Sonia Ancoli-Israel, 2002[48] | 77 dementia patients | 1.0 m | 2500 lux bright ligh tor <50 lux red light | 9:30 am to 11:30 am and 5:30 pm to 7:30 pm for 10 days | Scales and actillume recorder | Increasing exposure to morning bright light delayed the acrophase of the activity rhythm and made the circadian rhythm more robust. |
| Constantine G Lyketsos, 1999[53] | 15 AD patients | 3 feet | 10,000 lux bright light and dim, digital, low-frequency blinking light | 1 h in the morning for 4 weeks and for an additional 4 weeks in the other condition | Scales and sleep diaries | Patients sleep more hours at night when administered morning BLT. |
| Glenna A. 2008[47] | 70 AD patients | 4 feet | 2500 lux bright light or indoor light | 09:30 am to 10:30 am or 3.30 pm to 4.30 pm Monday through Friday for 10 weeks | Scales and actigraphy | One hour of bright light, administered to subjects with AD either in the morning or afternoon, did not improve nighttime sleep or daytime wake compared to a control group of similar subjects. |
| Lisa L. Onega, 2016[56] | 60 dementia patients | 27 inches | 10,000 lux bright light or 250 lux dim light | 30 min twice a day (8:00 am to 12:00 pm, and 2:00 pm to 8:00 pm), five times a week for 8 weeks | Scales and actigraphy | Bright light exposure was associated with significant improvement in depression and agitation. |
| Barbara B, 1995[57] | 6 dementia patients | 1.0 m | 2500 lux bright light | 09:30 am to 11:30 am for two 10-day periods. | Scales | BLT can reduce agitation. |
| Alistair Burns, 2009[12] | 48 dementia patients | – | 10,000 lux bright light or 100 lux dim light | 10:00 am –12:00 am for 2 weeks | Scales and actigraphy | BLT is a potential alternative to drug treatment in people with dementia who are agitated. |
| Andre Graf, 2001[55] | 23 AD or VD patients | 90 cm | 3000 lux bright light or 100 lux dim light | 2 h from 5:00 pm to 7:00 pm for 10 days | Scales and body temperature | Short-term evening BLT may exert beneficial effects on cognitive functioning in patients with dementia. |
| Rixt F, 2008[10] | 189 dementia patients | – | 1000 lux bright light or 300 lux dim light | Between 10:00 am and 5:00 pm for 15 months | Scales and actigraphy | Light can improve some cognitive and noncognitive symptoms of dementia. |
| Ann Louise Barrick, 2010[58] | 66 dementia patients | – | 2000 lux bright light | am bright light (7–11 am), pm bright light (4–8 pm), all day bright light (7 am –8 pm); or standard light for 3 weeks | Actigraphy | BLT does not appear promising as a treatment for agitation. |
AD: Alzheimer disease; BLT: Bright light therapy; VD: Vascular dementia.