November 22, 2012
Researchers Believe They Are On The Right Track For An Antidote For Hypersomnia
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Connie K. Ho for redOrbit.com — Your Universe OnlineA new study by scientists at Emory University found that some patients who suffer from hypersomnia also have an antidote in their cerebrospinal fluid that works similarly to a sleeping pill.
In particular, hypersomnia occurs when individuals have a higher need for sleep. This sleep disorder will make it difficult for people to wake up, with some sleeping over 70 hours. The effects of hypersomnia can hurt people´s progress in school and work, making it difficult for them to focus on tasks and assignments. According to Fox News, the strange molecule, otherwise called “somnogen,” is thought to cause the condition. The research on the sleep disorder first started five years ago when a patient, an Ivy League-graduated lawyer, slept as much as 57 hours consecutively.
"These individuals report feeling as if they're walking around in a fog — physically, but not mentally awake," remarked the study´s lead author Dr. David Rye, a professor of neurology at Emory University School of Medicine, in a prepared statement. "When encountering excessive sleepiness in a patient, we typically think it's caused by an impairment in the brain's wake systems and treat it with stimulant medications. However, in these patients, the situation is more akin to attempting to drive a car with the parking brake engaged. Our thinking needs to shift from pushing the accelerator harder, to releasing the brake."
The clinical study included seven patients who reported feeling sleepy even after normal amounts of sleep and treatment with stimulants. In some cases, the participants became more alert with the drug flumazenil but it wasn´t seen with all seven patients. In the past, flumazenil has been used for overdoses of benzodiazepines, a commonly used type of anesthetic and sedative. The researchers measured the alertness of the study subjects with a psychomotor vigilance test, which tracked reaction time.
"Primary hypersomnias are disabling and poorly understood. This study represents a breakthrough in determining a cause for these disorders and devising a rational approach to therapy," explained Merrill Mitler, who serves as a program director at the National Institute of Neurological Disorders and Stroke, in the statement. "Further research is required to determine whether or not the results apply to the majority of patients."
The researchers found that the cerebrospinal fluid in the patients was not a benzodiazepine drug. They believed that the fluid has a substance that improves the effects of gamma-amino butyric acid (GABA), a chemical in the brain. Considered one of the inhibitory chemicals in the nervous system, GABA can be enhanced by alcohol, barbiturates, and benzodiazepines.
"In some of the more severely affected patients, we estimated the magnitude of the GABA-enhancing effect as nearly equivalent to that expected for someone receiving sedation for outpatient colonoscopy," noted Rye, who also works as the director of research for Emory Healthcare's Program in Sleep, in the statement. "This is a level of impaired consciousness that many subjects had to combat on almost a daily basis in order to live their usual lives."
Researchers are not clear as to the makeup of the GABA-enhanced substance. The team of investigators posits that it could be peptide due to its size and response to specific enzymes. Further investigation of the body-produced substance could help the group of scientists better understand how the brain moderates states of consciousness like alertness and sleep.
"In some of the more severely affected patients, we estimated the magnitude of the GABA-enhancing effect as nearly equivalent to that expected for someone receiving sedation for outpatient colonoscopy," concluded Rye in the statement. "This is a level of impaired consciousness that many subjects had to combat on almost a daily basis in order to live their usual lives."
Other medical experts believe that the results of the findings are important. According to Bloomberg News, hypersomnia is so debilitating that some of the study participants applied for disability and others took time away from school and work to rehabilitate.
“It´s a breakthrough,” remarked Rochelle Zak, a sleep medicine specialist at the University of California San Francisco Medical Center, in an interview with Bloomberg News. “It gives a mechanism for doing clinically relevant future studies, both in terms of understanding the mechanism and in terms of developing an effective therapy.”
The research findings were published recently in the journal Science Translational Medicine.