Braille Monitor                                                 March 2012

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Rare Sleep Disorder Leaves Some Who Are Blind Out of Sync

From the Editor: The authors of many studies conducted on blind people ask the NFB to participate. Some we regard as having merit and join in them. Others seem to study issues having nothing to do with blindness, and we politely decline to be a part.

Many of us who are blind experience trouble sleeping. While it is undoubtedly true that, as a cross-section of human beings, some of our sleep problems relate to those shared with the sighted, the proportion of blind people having sleep difficulties indicates that a study to determine what part blindness plays and to find a solution is in order. For this reason we have publicized the efforts of Vanda in promoting its study and are glad to run this article, which they have asked us to include in the Braille Monitor:

So much for drinking a warm glass of milk or counting sheep when you cannot sleep. Those remedies may work for others who toss and turn at night but not for people who have a rare and under-recognized sleep disorder called Non-24-Hour Sleep Wake Disorder (N24HSWD), a chronic circadian rhythm sleep disorder that occurs when individuals are unable to synchronize their internal clock to the 24-hour light-dark cycle. As a result the sleep-wake cycle of these people moves gradually later and later each day if their circadian period is more than 24 hours or earlier and earlier if it is less than 24 hours. This condition occurs almost entirely in those who are totally blind and lack the light sensitivity necessary to reset the circadian clock.

Exposure to daylight provides cues to the brain that help organize daily life. It sets the hands of the body’s master clock, a tiny pair of nerve clusters in the center of the brain that anchor body rhythms to the earth’s twenty-four-hour light/dark cycle. In blind people lack of environmental cues like daylight block an important signal to the brain that enables synchronized patterns.

People with N24HSWD suffer from cyclic insomnia and sleep deprivation, which may lead to difficulties with concentration and memory, as well as an increased risk of errors and accidents. For some totally blind people the sleeplessness and daytime fatigue have significant impact on their social and occupational lives and are considered the most disabling aspect of blindness.

At this time no treatment has been approved by a pharmaceutical regulatory authority for N24HSWD in blind people without light perception. The good news is that help may be on the way. Over a year ago Vanda Pharmaceuticals, a specialty pharmaceutical company based outside of Washington, D.C., launched an important clinical research study to evaluate a potential treatment for N24HSWD. The company has made significant strides in educating the public on N24HSWD and collaborating with the NFB to make information available to people who may suffer from the disorder. In addition, Vanda has developed a survey to help identify people who may qualify for its research study. For every completed survey, Vanda will donate $25 to the NFB. Those who are interested are encouraged to call (888) 389-7033 or visit <> as soon as possible.

According to a Vanda press release, the company has been able to prove that a drug, Tasimelteon, does in fact help in resetting the body clock in people with Non-24. This is the first time that a pharmaceutical agent has been able to do this in patients with Non-24. For updates on progress in this area of research, please continue to check <>. For more information and references about Non-24-Hour Sleep Wake Disorder, visit <>.

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