Can light therapy be beneficial for Alzheimer's patients?

I found this interesting quote today: "Clinical research has shown that exposure to very bright light in the day and darkness at night can consolidate rest and activity patterns in AD patients.2 This clinical research was based on more basic studies of circadian regulation by light exposure in animals and humans.3,4 This large and growing body of research shows that bright light during the day is a powerful means of entraining natural circadian rhythms in all species, including humans. Depending on the timing, duration, intensity, and spectrum of the light, circadian rhythms can be synchronized or desynchronized (phase advanced or phase delayed) with the natural, 24-hour, daylight/darkness pattern." Source: http://sandygrdn.blogspot.com/2009/12/light-therapy-and-alzheimers-disease.html I would like to know whether exposure to full spectrum lighting conditions during the day time can prove beneficial for patients suffering from Alzheimer's disease?