A new study has discovered a method on how to correct the sleep problems
of the blind.

kelly





The New York Times: June 22, 1999
Melatonin Used to Restore Sleep Patterns in Blind People
By ERICA GOODE

 In the early 1970's, Dr. James Stevenson, then a graduate student in
psychology at Stanford University, developed a theory about why he had
so much trouble sleeping.
Dr. Stevenson, who had been blind from birth, suffered insomnia at
night, and in the daytime experienced "sleep attacks," which arrived
one hour later each day, playing havoc with his efforts to get to
classes on time.
He had read that in blinded animals, the body's clock, normally
harnessed to the 24-hour cycle of daylight and darkness, often goes
into free run, shifting sleep patterns. His own sleeping difficulties,
Dr. Stevenson suspected, might have a similar origin.
A sleep researcher, Dr. Laughton Miles, later confirmed what Dr.
Stevenson had concluded: In the absence of light, his body had taken
up a free-running, 24.9-hour circadian rhythm of sleep and
wakefulness, a schedule that shifted his natural sleeping time back by
nearly an hour each day.
But Dr. Miles, who in 1977 published a scientific report on Dr.
Stevenson's case, could find no way to fix the problem, nor could
other researchers, who have spent two decades seeking effective
treatments for the sleep problems caused by free-running circadian
rhythms, which affect about half the 200,000 Americans who are totally
blind.
If a study to be presented Tuesday at the annual meeting of the
Associated Profession Sleep Societies in Orlando, Fla., holds up,
however, the search may finally be over.
Dr. Robert L. Sack, Dr. Alfred J. Lewy and Richard W. Brandes of the
Sleep and Mood Disorders Laboratory at Oregon Health Sciences
University, are scheduled to present their finding that a daily
10-milligram dose of the hormone melatonin successfully "entrained"
the free-running rhythms of 6 out of 7 totally blind subjects,
returning them to a normal, 24-hour sleep pattern.
"Even entraining one blind person with melatonin is important," said
Dr. Charmane Eastman, director of the Biological Rhythms Research
Laboratory at Rush Presbyterian-St. Lukes Medical Center in Chicago.
The new study, she said, has implications not only for the blind, who
often list sleep problems as one of the most difficult aspects of
their disability, but also for sighted people, whose circadian rhythms
can be altered by jet lag or shift work.
Dr. Lewy, director of the sleep lab at Oregon, said, "Totally blind
people offer a natural way to study the human body clock, without the
interference of light cues."
In an earlier study, the researchers tried using a 5-milligram dose of
melatonin without success. "We got some shifting of rhythms, but we
weren't able to establish a clear 24-hour cycle," Dr. Sack said.
A few otherinvestigators have reported single cases in which melatonin
corrected free-running sleep-wake cycles in blind people. And Dr.
Stevenson, now a research psychologist at NASA Ames Research Center in
Mountainview, Calif., said he began taking melatonin before bedtime in
1987, and now sleeps normally. But the new study compared melatonin
with placebo pills in a group of subjects.
Melatonin is secreted by the pineal gland -- a tiny structure deep in
the brain -- and helps regulate the body's biological clock. In
sighted people, melatonin secretion is synchronized with the 24-hour
cycle of daylight and darkness, turning on at nightfall, and
continuing for about 12 hours. But in the absence of light, most
people's body clocks run on a cycle slightly longer than 24 hours, Dr.
Sack said.
The hormone is also sold over the counter as a nutritional supplement,
usually in 3-milligram tablets. Taken in the afternoon, it shifts the
body's clock earlier, tricking it into thinking dusk has already
fallen. Taken in the morning, however, it delays the clock, as if dawn
had not yet arrived.
Scientists still know little about the effects of melatonin at
different dosages: In sleep studies, researchers have used doses as
small as .3 milligrams and as large as 75 milligrams or higher. Dr.
Sack said for some blind people 10 milligrams may be more than is
needed. He and his colleagues are conducting further research to see
if dosages between 5 and 10 milligrams are equally effective.
In the study, the subjects, who did not know which treatment they were
receiving, took melatonin an hour before bedtime for a period of
weeks, then were switched to a dummy pill, or vice versa. The length
of time it took for the melatonin to shift rhythms back to normal
varied from person to person. "Without knowledge of a person's
circadian phase," Dr. Sack and his colleagues wrote, "it may be
difficult to know the best day for initiating melatonin treatment;
thus entrainment may not occur for weeks or months."
Clifton Zang, a 47-year-old man from Portland who has been totally
blind since being hit in the head by a stray bullet while sitting in
his pickup truck 16 years ago, said the benefits of melatonin became
apparent not long after he started taking the supplement. "Before the
study, I had no control of my sleep," Mr. Zang said. "I'd sleep any
time of the day or night. I'd be awake at 2 in the morning and fall
asleep at noon. But since I've been on the melatonin I go to sleep at
11 o'clock and wake up at 5, 6 or 7."


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