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Non-24-Hour Sleep-Wake Disorder in Blind Individuals

  • Published: 2011-07-08 (Revised/Updated 2017-06-14) : Author: Vanda Pharmaceuticals
  • Synopsis: For someone with Non-24-Hour Sleep-Wake Disorder (N24HWD or Non-24) their internal body clock changes every day.

Main Document

"Patients suffering from Non-24 experience severe insomnia and excessive daytime sleepiness, which often interferes with social, family and work obligations."

New website targets common sleep disorder in blind individuals - offers interactive tools and research updates to assist patients, friends and family.

For most people, the clock changes just twice a year for Daylight Saving Time. But for someone with Non-24-Hour Sleep-Wake Disorder (N24HWD, or Non-24), their internal body clock changes every day.

In the U.S. alone, it is estimated that approximately 65,000 - 95,000 people suffer from Non-24, a sleep disorder in which a person's sleep period can advance by about 15 minutes each night.

Patients suffering from Non-24 experience severe insomnia and excessive daytime sleepiness, which often interferes with social, family and work obligations.

Non-24 is most common in the totally blind who lack light perception and affects more than 50 percent of this population. Sighted people can experience similar sleep or circadian rhythm disorders as well, in the form of jet lag or from night shift work.

Vanda Pharmaceuticals Inc. launched to promote awareness and support for those who may suffer from Non-24. Utilizing the website, people can access helpful information and research articles, listen to interviews conducted with medical experts, and learn about clinical trials.

"'Non-24' is a serious health condition and, because many doctors themselves are unaware of the disorder, people can go undiagnosed for years. Though there's still no cure, it's important to have a place for people to go and learn about this condition, know that they're not alone, and then talk to their doctor about their options," said Melanie Brunson, Executive Director of the American Council of the Blind.

Circadian Rhythm

Circadian Rhythm is the daily activity cycle that drives the rhythms of our body- from digestion to hormone secretions to our ability to sleep.

The timing of human sleep is governed by the length of time since a person last slept and by their internal body clock. The body clock or circadian clock controls the timing of human sleep with a rhythm that is regulated by a region of the brain called the suprachiasmatic nucleus (SCN). The SCN, located in the hypothalamus, sends signals to help us stay awake and counteract the effects of fatigue. These signals peak in the evening, when the drive for sleep is high, and then diminish when bedtime approaches.

In most people, the sleep/wake circadian rhythm is maintained on a 24-hour day cycle and determined by the light exposure they get in the morning or evening. When a person's body clock is mismatched with their sleeping and waking schedule, it may create a circadian rhythm sleep disorder.

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