Sept. 24, 2010 -- Ellen Vincenti went through a two-and-a-half day stretch she wil never forget. She spent that time stuck in a remote swamp in the woods about 15 miles from her home in Tuftonboro, New Hampshire.
"I managed to get up on a tiny piece of land, but the water was waist-deep around me," said Vincenti.
What was worse was the fact that she has no idea how she got there.
"Saturday night, I kissed my husband goodnight. I took the new medication I was on and said I was going to read until I'm tired. The next thing I knew, it was 5:30 Sunday morning and I was in my car in the middle of the woods," said Vincenti.
Vincenti said she was disoriented at that point, and walked in the direction of the traffic she heard. After that, she said she found herself waist-deep in water.
"I spent Sunday screaming for help, but no help came," she said. She kept on screaming, and help finally came on Tuesday after a woman living nearby heard her.
Vincenti was shaken by the incident but otherwise uninjured. She said her doctor told her the medication she was taking, which she did not want to disclose, was the likely trigger of her nighttime excursion. She also said she has a history of sleepwalking and sleep talking.
Sleepwalking is perhaps the most well-known form of parasomnia -- a disorder that interrupts sleep and often involves disruptive behaviors -- but experts say there are others that can either be very milid or cause severe disturbances. The next few pages feature a closer look at some of these disorders.
The fact that Vincenti somehow got in her car and ended up getting stuck in the woods is uncharacteristic of most sleepwalkers, though experts say it can happen.
"An extreme case is the individual who actually gets out of the house," said Dr. Helene Emsellem, director of the Center for Sleep and Wake Disorders in Chevy Chase, Md.
"In general, the furthest they go is the next room," said Joyce Walsleben, associate professor of medicine at the NYU School of Medicine.
Experts say a number of factors can contribute to sleepwalking, including certain medications, stress and sleep deprivation. It's most common in children between the ages of 8 and 12, and they outgrow it by their early teens.
"It typically happens coming out of deep sleep, so sleepwalkers are half in and half out of arousal," said Walsleben.
People who sleepwalk don't remember what they did during an episode. While most don't involve any serious or life-threatening incidents, there have been a number of high-profile cases of crimes that were committed by people who said they were sleepwalking.
One recent case concluded this past August. A Bloomington, Ill. man was acquitted of sexual assaulting a woman after a party. He said he was sleepwalking and had no memory of the incident.
A London man became an Internet celebrity after his wife posted videos of him talking in his sleep on a blog.
Adam Lennard blurted out things like, "Elephants in thongs are not something you see every day. Enjoy it," and "Vampire penguins. Zombie guinea pigs. We're done for. Done for."
Outbursts like these are characteristic of sleep talking. They can be funny and sometimes graphic.
"You'll wake up for a second and say something," said Walsleben. "It tends to happen in the earlier part of the night when you're going from deep sleep into lighter sleep."
"If it happens during REM sleep [the stage characterized by rapid eye movements], it could be associated with dreaming," said Dr. Mark Dyken, professor of neurology at the University of Iowa College of Medicine.
Sleep talking can be caused by stress, certain medications and certain mental illnesses. Experts estimate about half of all children between the ages of 3 and 10 talk in their sleep, and about 5 percent of adults do it.
If talk becomes violent, that's a characteristic of a more serious disorder known as REM behavior disorder.
"There will be screaming, yelling, punching and other outbusts, such as flying out of bed or lunging at something," said Walsleben.
REM behavior disorder is most common among older men. It's caused by a deterioration in the brain, Walsleben said.
There are often stories of people who wake up with crumbs in their bed but have no idea how they got there, or people who walk into their kitchen in the morning and find it inexplicably in complete disarray. People may also find that they've eaten bizarre things, like cigarette butts or flour.
Sleep experts believe there are a number of factors that contribute to sleep eating.
"If you go to bed hungry, your stomach is going to win," said Emsellem.
Certain medications can also precipitate sleep eating.
"Ambien is known to increase the risk of nocturnal eating," said Emsellem. She also said selective serotonin reuptake inhibitors -- antidepressants similar to Prozac -- can also lead to sleep eating episodes.
Stress can also play a role, especially if someone is dieting and focused heavily on food during waking hours.
Dyken also suggested the roots of sleep eating are planted during infancy and childhood.
"Parents sometimes feed kids late at night, and they wake up becasue their rhythms are off and have adpated to being hungry at night. It's induced by parents who have been negatively conditioned by a hungry child," said Dyken. "This has developed into a patient wandering around and going to the kitchen."
Sleep deprivation and improper use of sleep medication are two causes experts believe contribute to the phenomenon of texting while asleep.
Studies have shown that tech-crazed kids frequently lose a lot of sleep over those gadgets they can't put down, but that could cause them to send messages they can't even remember.
"Some of these kids are working on fumes. They just have to text and it interferes with getting into sleep. They may actually be in an early stage of sleep when they're texting," said Dyken.
Adults who take sleep medication incorrectly may also find themselves sending text messages or e-mails while asleep.
"People need to be in a dark room and in bed when they take sleep medication," said Walsleben. "A lot of times, they'll just take it and think they have 20 minutes or so to send an e-mail or a text message."
Sex during sleep, or sexomnia, is a sub-category of the parasomnias known as confusion arousals, according to Dyken. Confusion arousals occur when a person is in a mixed state of being both asleep and awake.
A recent study in the Journal of Sleep Research analyzed more than 800 people suspected of having sleep disorders. The study found that about 8 percent of them were having sex while they slept.
"There's probably a lot more of it going on than people like to talk about," said Emsellem.
Sexomnia is characterized by an extreme level of sexual arousal, and people who exhibit it may masturbate or engage in sexual activity with their partner lying next to them and not remember it.
"It's very troubling to patients and their bed partners," Emsellem said.