Characterized at its extreme by physical convulsions, epilepsy has long been thought to cause excitability and contrariness in children. But UF researchers writing in the journal Epilepsy & Behavior believe the real reason some of these children cannot sit still or pay attention is because they don't get enough shut-eye.
"When we treated kids with sleep disturbances, not only did their epilepsy get better, their daytime behavior, concentration and capacity to learn increased," said Dr. Paul Carney, chief of pediatric neurology at UF's College of Medicine and a professor at the B.J. and Eve Wilder Center for Excellence in Epilepsy Research. "Many kids with epilepsy aren't being adequately assessed for underlying sleep disorders. We can significantly have an impact over their cognition, learning and maybe even improve their epilepsy by improving their sleep."
Epilepsy describes a group of disorders that occur when electrical activity in the brain goes haywire, resulting in bursts of frenetic activity that cause seizures. It strikes more than 2 million people in the United States, according to the National Institute of Neurological Diseases and Stroke.
UF scientists monitored the brain and muscular activity of 30 children with epilepsy between the ages of 7 and 14 during single overnight stays. None of the children had seizures, but some awoke hundreds of times because of breathing problems.
In all, 24 of the children -- 80 percent -- breathed shallowly or had breathing disruptions caused by apneas, which usually happen when the soft tissue in the rear of the throat relaxes during sleep and blocks a person's airway.
As the breathing disruptions increased in duration, the children spent less time in rapid eye movement, or REM, sleep, a period in the sleep cycle when brain activity is highest and people dream intensely. The children in the study spent 17 percent of total sleep time in the REM stage. The norm for young adults is 25 percent.
"Removing the sleep problem does seem to improve the behavior problem significantly, because it changes the child's level of alertness," Carney said. "Commonly, adults are just not as awake if they have a sleep disorder. But children who haven't taken their nap are wound up instead. Treating their sleep disorder, we think, can enable their brain to have some control over unwanted behavior."
Seventy-three percent of the children studied -- 22 of the 30 -- met clinical criteria for inattention or hyperactivity, according to Carney, who conducted the research with Eileen Fennell, a child neuropsychologist in the College of Public Health and Health Professions, and Danielle Becker, M.S., a former graduate student now pursuing a medical degree.
Of these 22 children, each had a sleep disorder, 14 had problems paying attention during the day and eight had hyperactive symptoms, supporting the idea that a poor night's sleep is associated with children's daytime attention problems. UF scientists found no correlation between seizure frequency and behavioral problems. Epilepsy alone did not appear to predispose them to behavioral problems.
Research with different groups of children is now under way to determine whether treatment of sleep disorders will reduce seizure frequency and severity, and to more fully understand the effects of sleep disorders on children's behavior and cognitive abilities. A tonsillectomy is a common treatment for sleep apneas in children.
In general, scientists don't know exactly why people need sleep, but it is vital for good memory, physical performance and psychological well-being, according to the National Institutes of Health. Some experts believe sleep gives brain cells a chance to shut down and repair themselves. Sleep also may allow the brain to exercise important connections that might wither from lack of activity.
"The fact is we don't know all of what's going on in terms of sleep disorders and epilepsy," said Dr. Beth Malow, an associate professor of neurology at Vanderbilt University and director of the Vanderbilt Sleep Disorders Center. "We've seen that identifying and treating sleep disorders help with epilepsy in adults. It may be sleep deprivation or drowsiness contributes to seizures. Or it could be the frequent going into and out of sleep. People with sleep apneas also have increased production of proteins that help regulate the immune system called cytokines, which are known to promote seizures. It's going to take a lot more research before we find all the answers."