When Patricia Riccio says she wants Alzheimer’s patients to see the light, she is not talking about a religious experience. Rather, the assistant professor of nursing will be exposing Alzheimer’s patients to a bright light therapy that may help with the sleep problems experienced by many with the disease.
Riccio recently received a grant from the Hoechst Marion Roussel Foundation and the Neuroscience Nurse Foundation to study the effects of bright light on the circadian rhythms of Alzheimer’s disease patients. “There is good evidence to suggest that light has an effect,” she said. “Bright light treatment can act as nonpharmacological intervention by phase delaying the sleep/wake circadian rhythms.”
Circadian rhythms – the biological processes such as sleep and waking – cycle approximately every 24-hours. They are regulated through a mechanism in the hypothalamus, the superchiasmatic nucleus, that gets its timing information from light striking the retinal fibers of the eye. Natural light “signals” the body that it is daytime, or time to be awake, or nighttime, or time to sleep.
As aging occurs, however, the body clock may actually speed up, said Riccio. “With Alzheimer’s patients, it may be shifted even further, creating such an advanced rhythm that patients will go to bed earlier, wake up earlier, have a hard time maintaining nighttime sleep schedules and have increased daytime sleepiness.”
“We’re hoping that by exposing them to bright light in the evening, the effect will be a slowing down of the circadian sleep/wake phase,” she said.
A few studies have already looked at the effect of light exposure on sleep/wake cycles, but “many of those have used light boxes which restrain the patient in front of light box,” she said. “What’s different here is that I’m using a portable light visor so patients can be a lot more mobile. It works with a battery pack, and they can do anything they want to do.”
The visor, in fact, was developed by Bethesda-based Biobright Inc. for treating jet lag.
Another advantage of the visor, said Riccio, is that “by having light focused close to the retina, there could be more dose control of the light.”
For the study, patients will wear wrist “actigraphs” for several days to establish and record rest and activity patterns. Then for seven days the patients are exposed to the bright light for several hours in the evening before bed. A control group will receive exposure to dim light. Then the light visor is removed and the patient’s sleep cycle is monitored with the wrist actigraph.
Riccio said she is collaborating with physicians at the Netherlands Institute for Brain Research in Amsterdam and the Akita University School of Medicine in Japan to determine the how long the bright light therapy should be administered and what the “dose” should be to have the greatest effect. “Preliminary data shows we may have to increase the exposure,” she said. Anyone interested in joining the study should call Riccio at 342-2010.