NEWS RELEASE, 6/1/99
Microsoft keyboard beats the competition, cuts hand pain 50 percent, new UC study shows
By Kathleen Scalise, Public Affairs
BERKELEY--Surprising results are in from the first long-range study of alternative computer keyboards and hand discomfort.
After investigating several commercial keyboards marketed to reduce typing aches and pains, University of California researchers found that one - the Microsoft Natural Keyboard - performed significantly better than its rivals and cut hand pain by 50 percent over six months. They report their findings in the June issue of the American Journal of Industrial Medicine.
"The results were unexpected," said David Rempel, a UC Berkeley bioengineering professor and UC San Francisco professor of medicine. "We didn't expect a dramatic difference between keyboards."
Besides the Microsoft product, his group examined the Apple Adjustable Keyboard, the Comfort Keyboard System and placebo keyboards in the first controlled, randomized workplace study to last more than a few weeks.
Rempel said the technology revolution has led to greater hand, shoulder, neck or arm problems in 20 to 60 percent of the workforce in industries where heavy computer use is common, including financial services, programming and telecommunications.
"This is an important public health problem and will only grow as we spend more time on computers," he said.
Eighty Lawrence Livermore National Laboratory employees diagnosed with possible carpal tunnel syndrome or tendonitis participated in the experiment. All had hand pain or numbness attributed to computer use. Each was randomly assigned one of the trial keyboards or a "placebo" keyboard, which was made from the subject's own computer equipment modified to appear enhanced.
For six months, the subjects "did all their usual work with the keyboard they were assigned," said Rempel. "Every six weeks we had them fill out a form to assess hand pain and function, and they had physical examinations at the beginning and the end of the study."
At the end of six months, only the Microsoft keyboard users showed improvement. These workers reported pain severity scores 50 percent lower than at the beginning of the research study. Pain for other subjects remained essentially constant.
Rempel said all three of the keyboards studied are split in the middle. The Comfort keyboard is the most complex and can adjust in many different ways, both vertically and horizontally. The Apple keyboard rotates outward in a fixed plane away from the center. The Microsoft design is fixed and essentially non-adjustable. However, it keeps the wrists straighter than a standard keyboard and rotates the hands so that the palms begin to face each other. "
It took awhile before improvement occurred with the Microsoft keyboard," said Rempel. "Pain improvement only became noticeable after about twelve weeks. The lesson here is that when people begin to modify their keyboard, mouse or workstation, it may take two or three months before there is an effect."
Rempel said this is the first such long-range study in the workplace. Most ergonomics experiments in the past have lasted only two weeks or less, he said. Mixed results have left an unclear picture of what attributes keyboards should have. Rempel believes such experiments must last at least several months to yield valid data.
The UC group does not know why the Microsoft keyboard fared best in the recent trials, but Rempel suspects the keyboard structure may hold the wrist in what is called a "neutral" position, causing less stress on nerves and tendons at the wrist.
Also, "the other adjustable keyboards gave more choice and it may be that users did not select the appropriate postures," he said.
Among the scientists on the study were Lawrence Livermore researchers Pat Tittiranonda, formerly a UC Berkeley graduate student, and Stephen Burastero, an occupational medicine physician. Thomas Armstrong of the University of Michigan Center for Ergonomics in Ann Arbor also participated. The U.S. Department of Energy funded the study.
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