The onset of dementia in an aging relative can be a devastating thing to watch, as memory and cognition slowly degrade. But a new study suggests one easy thing you can do to help hold back the fog: Turn on bright lights, and keep them on all day. The study in the Journal of the American Medical Association[subscription required] suggests that this simple intervention may boost a patients' cognition by reinforcing the body's circadian clock, the sleep-wake cycle that can be modulated by daylight.
When the circadian rhythms are disrupted (as in a case of jet-lag), the brain releases hormones and other agents that can affect cognition. Elderly dementia patients have several difficulties with their circadian clocks. The part of the brain that governs the sleep-wake cycle, the hypothalamus, becomes less active with age, and patients in long-term care facilities or hospitals tend to spend less time outside in the sunshine.
The study indicates that bright lights can partially make up for those handicaps. Researchers looked at patients with dementia in several long-term care facilities in the Netherlands, and compared patients who were exposed to very bright lights for nine hours a day to those whose environments were dimmer. They found that the patients who had been bathed in light not only had better scores on cognitive tests, they also had much fewer depressive symptoms. Earlier studies have also indicated that well-lit environments decreased insomnia in Alzheimer's patients. The lights the researchers used aren't the kind you have around the house:
In the study, [lead author Eus] Van Someren's group used 1,000-lux bulbs in overhead lights, which is equivalent to the brightness of television studio lights, and compared their effects to those of 300-lux bulbs, which are found in office and retail settings [Time].
One of the symptoms of dementia and Alzheimer's is the disruption of sleep cycles, and researchers hypothesize that the hypothalamus is being affected in other ways that aren't yet understood. Regardless of the cause, people who take care of family member in their homes often struggle to cope with a patient who doesn't follow normal sleep patterns. One expert, Dr. Michael Hastings, said these disturbances could be the "final straw" for caregivers.
"You can have a situation where someone is asleep for part of the day, then at 3am will be awake, wandering around the house, turning the gas on. Relatives can manage quite a few of the symptoms of mild or moderate dementia, but this can be too much" [BBC News].
Researchers in the current study pointed out that the improvement they saw in cognition just from the lighting change was about the same as the cognition boost provided by some Alzheimer's drugs. As light therapy is an easy, non-invasive technique, Van Someren suggested that hospitals, care facilities, and even households should bring on the wattage.