Computers and Carpal Tunnel Go Hand-in-Hand -- Or Do They?
This is Part 1 of a two-part series
June 11, 2001 -- Office workers can "breathe a sigh of relief," according to a Mayo Clinic researcher. Contrary to popular belief, a new study shows that using a computer doesn't appear to increase the risk of developing carpal tunnel syndrome. The study appears in today's issue of the journal Neurology.
"The popular thought is that computer use confers a risk of carpal tunnel syndrome. We were expecting to find an increased risk, and when we didn't, we were surprised," author J. Clarke Stevens, MD, tell WebMD.
"We basically looked at people who used the computer keyboard heavily -- that is between 6-7 hours a day -- to find out how many of those people had carpal tunnel syndrome, and we found ... that this heavy computer keyboard use did not increase the risk of carpal tunnel," says Stevens, a neurologist at the Mayo Clinic in Rochester, Minn.
The carpal tunnel is a bone-and-ligament passageway between the forearm and the hand, at the wrist. The median nerve, which supplies feeling to the thumb, index and ring fingers, and the tendons that bend the fingers, passes through this tunnel.
Usually, carpal tunnel syndrome is considered an inflammatory disorder caused by repetitive stress, physical injury, or other conditions that cause the tissues around the median nerve to swell. The swelling compresses the median nerve fibers, which in turn interferes with the transmission of nerve signals through the carpal tunnel. The result is pain, numbness, and tingling in the wrist, hand, and fingers, except the pinkie finger, which is not affected by the median nerve.
In the study, Stevens and his colleagues contacted more than 250 Mayo Clinic employees who used computers an average of six hours a day for their jobs. Approximately 30% said they had experienced numbness or pins-and-needles in their hands, but only 27 met the criteria for a diagnosis of the syndrome.
Nerve studies to confirm the diagnosis, however, found that only nine people actually had carpal tunnel syndrome. That's 3.5% of the original "heavy" computer users studied -- a percentage similar to that found in the general population.
Additionally, those with carpal tunnel were not any different -- in terms of type of occupation, years on the job, number of hours on the computer per day -- from those without the syndrome, leading the researchers to conclude that using a computer "heavily" does not enhance the risk of carpal tunnel syndrome.
"It has been known that certain occupations outside of the office -- for example, using jack hammers, working in the meat packing industry, working in factories, where, thousands of times a day, a single repetitive action is done using the hand and wrist -- do increase the risk of carpal tunnel syndrome, and ... people thought that perhaps computer keyboard use is a different kind of repetitive motion activity and, therefore, also increases the risk," says Stevens. "But this study would suggest that does not seem to be the case."