PORTLAND, Ore. (AP) - Researchers at two Oregon hospitals are studying a common but rarely diagnosed ailment that causes millions of Americans to have a creepy-crawly feeling deep in their leg muscle or involuntarily kick their legs.
The neurological condition, called restless leg, is a nuisance, not life-threatening. But restless leg sufferers are driven to sometimes extreme lengths to move their legs, about the only thing that brings immediate relief.
Researchers at Oregon Health & Science University and Bend Memorial Clinic are participating in national studies to see how effective certain medicines are in treating the condition.
Both studies involve drugs that increase the level of a hormonelike substance called dopamine, which is essential in transmitting nerve impulses. Researchers at OHSU are looking at a drug called Requip, a dopamine prescribed for Parkinson's disease. In Bend, researchers are trying sumanirole, a new drug that shows promise for both Parkinson's and restless leg.
Although the drugs are designed to treat Parkinson's disease, a progressive nervous system disorder, doctors are quick to point out that restless leg and the more serious Parkinson's are not related.
The best estimates of restless leg syndrome's prevalence range from 6 percent to 15 percent of the adult population.
Although older people seem more vulnerable, children can have it, too. Some physicians think a small number of children diagnosed with hyperactivity disorders might actually have restless leg syndrome.
The ailment seems to run in families and is particularly prevalent in people with iron deficiency.
Newt Hagar, 84, a Portland resident, leads a support group for 20 to 30 restless leg sufferers who meet every other month.
Hager said whenever he relaxed in front of the television or started drifting off to sleep in bed, his legs will kick of their own accord, about once every 20 seconds. His legs will keep jerking throughout the night, making it impossible for his wife to sleep.
In movies or on airplanes, Hagar said he has an irresistible urge to get up and walk - about the only way he could make the kicking go away.
About 80 percent of those with restless leg syndrome also have Hagar's problem, legs that jerk during sleep.
Dr. Robert Sack, medical director of the OHSU Sleep Disorders Clinic and a restless leg researcher, says patients often have a hard time describing the disturbing feelings in their legs. As a result, they often don't talk to their doctors about the symptoms.
And even when they do, relatively few doctors know about restless leg.
"This is the most common disorder your doctor has never heard of," Sack says.