Scattered throughout past sleep research are a number of reports describing unusual behavior while sleepwalking, including sleep eating, sleep phone calls, sleep sex -- and even sleep rape and murder.
Now, a new case study is adding one more bizarre sleep phenomenon to the literature: sleep e-mailing.
In an article published in the journal Sleep Medicine, Seton Hall University researchers document the case of a 44-year-old woman who struggled with severe insomnia for years before she was prescribed the popular sleeping aid, zolpidem (also known by the brand name Ambien), in 2004.
The zolpidem helped with her insomnia at first, but the effects of the drug began to wear off after a period of time. Soon her doctor increased her dose, allowing her to get five hours of sleep per night.
But after starting this increased dose regimen, the woman received a puzzling phone call from a friend who said she was accepting her dinner invitation -- an invitation that she could not remember extending.
The woman's friend reminded her of the e-mail she'd sent the night before -- an e-mail of which the woman had no recollection. A search through her sent items folder recovered the following e-mail that she had apparently sent to her friend at 11:47 the previous night:
"I don't get it. Please explain Lucy! Come tomorrow and sort this hell hole out! Dinner and drinks, 4:00pm?Wine and caviar to bring only. Everything else, a guess?"
There were two other e-mails sent to her friend at 11:50 p.m. and 11:53 p.m., each of which seemed to be written in a strange language, full of capitalization errors and nonsensical phrases.
According to Dr. Fouzia Siddiqui, lead author of the case report and a neurologist at the University of Toledo, this particular sleepwalking case is unique; it is the first and only published case of "sleep e-mailing." But he says that it is even more notable for the amount of complex actions the woman had to take in order to compose these e-mails.
"Sleepwalking has occurred in the past where people will [conduct] other activities such as cooking or moving furniture around," Siddiqui said. "But this case is unique in that she wasn't just sleepwalking but doing things like turning on her computer, remembering her user name and password and typing entire e-mails."
Siddiqui said in this patient's case, the cause of her unusual sleepwalking episode was her increased zolpidem dosage. Siddiqui immediately reduced the patient's dose; since then, she has not had any episodes of sleepwalking.
Sleepwalking falls under the category of sleep disorders called parasomnia. Parasomnias are characterized by abnormal movements or behaviors that can occur in between sleep stages or from sleep arousal.
Studies on sleepwalking have found that somewhere between 5 percent and 10 percent of people are sleepwalkers.
Although this is the first case study reported on sleep e-mailing, Dr. Mark Mahowald, director of the Minnesota Regional Sleep Disorders Center at the University of Minnesota, said that he is no stranger to this phenomenon.
"Our group certainly has heard of e-mail sending and Web purchasing during sleepwalking," Mahowald said.
And while this phenomenon of sleep e-mailing is highly uncommon, most sleep experts agree that it is not so different from other types of sleepwalking episodes.