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TUESDAY, June 10, 2003 (HealthDayNews) -- Anecdotes and ergonomic keyboards aside, spending your days at the computer doesn't seem to greatly increase your risk of wrist problems.
That's according to Danish researchers who have found computer users don't face much if any increased risk of carpal tunnel syndrome, a condition believed to be caused in part by repetitive stress.
Their study finds those few who did have wrist problems should look not at their keyboard as a culprit, but at their mouse.
"It looks as if the occurrence of carpal tunnel syndrome is low in this group," says research leader Dr. Johan Andersen, an occupational medicine expert at Herning Hospital in Herning, Denmark. However, Andersen adds, "you should pay attention to your symptoms if you use a mouse more than 20 to 25 hours a week."
The findings appear in the June 11 issue of the Journal of the American Medical Association.
Carpal tunnel syndrome occurs when the tendons or ligaments in the wrist swell. In doing so they crowd the median nerve, which feeds the thumb and several fingers, leading to tingling, burning and numbness. The condition, which first crops up at night, can be treated, typically with immobilization, but more serious cases may only respond to anti-inflammatory drugs. In rare instances, doctors can perform surgery to relieve pressure in the wrist.
Previous studies have offered mixed results on whether people who work on computers are more likely to develop carpal tunnel symptoms. A 2001 study published in Neurology found no special link between computer use and the condition.
Andersen and his colleagues queried nearly 5,700 working Danes about their weekly computer use and their experience with signs of wrist trouble that might suggest carpal tunnel syndrome, such as persistent tingling or numbness in various parts of the hand. Most of the volunteers worked with computer-aided design software, spending between 2.5 and 15 hours a week typing and 10 to 25 hours a week using a mouse.
At the start of the study, roughly 11 percent of the men and women complained of tingling or numbness in their right hand. Interviews showed that between 1.4 percent and 4.8 percent may have had carpal tunnel syndrome.
A year later, 5.5 percent of the people had developed new symptoms of wrist distress. However, only 1.2 percent had median nerve problems that indicate true carpal tunnel syndrome. The risk appeared to be higher among those who used a computer mouse for at least 20 hours a week. However, no amount of keyboard typing was linked to the problems.
Why mouse use, but not typing, affects the wrist isn't clear, Andersen says, but it could have something to do with how the mouse arm is held. "You are more fixed in your positions when you work a lot with the mouse," he says.
Tingling and numbness in the hands could indicate carpal tunnel syndrome, the researchers write. But it's probable the symptoms reflect other medical conditions, such as trauma, "or are part of a large burden of medically unexplained symptoms that reflect the stresses and strains of everyday life."
More information
The National Institutes of Health and the National Library of Medicine have more on carpal tunnel syndrome.
