NO tool has characterized the modern workplace like the personal computer. An estimated 60 million PCs adorn desks in virtually every work environment today, achieving remarkable increases in productivity while virtually transforming entire industries. At the same time, however, an increasing number of employees are heavy computer users who suffer painful and sometimes debilitating (and occasionally career-ending) injuries called work-related musculoskeletal disorders (WRMSDs) involving their hands and arms.
According to Dr. Steve Burastero, director of Lawrence Livermore's Interdisciplinary Ergonomics Research Program and a physician in the Health Services Department, the mounting numbers of injuries should not come as a surprise. After all, someone typing 60 words per minute for 6 hours a day will keystroke a half-million keys every week, often in an awkward position or under stress.
Burastero says the number of cases of WRMSDs has increased dramatically to near-epidemic proportions in the U.S. workforce, from about 20% of occupational illnesses nationwide in 1981 to more than 60% of all occupational illnesses today, according to U.S. Bureau of Labor statistics. Within computer-intensive occupations, the incidence of injury has doubled every year for the past four years.
These disorders cost the nation over $40 billion per year in medical costs alone. When productivity losses and disability and retraining costs are included, the total bill may top $80 billion per year. A common injury is tendonitis--inflammation of tendons, which connect muscle to bone. Another well-publicized injury, carpal tunnel syndrome, involves damage to the median nerve that travels through a tight space in the wrist called the carpal tunnel.
Burastero notes that in the past, safety at most work sites, including Lawrence Livermore, traditionally focused on avoiding accidental injuries caused by hazardous materials or industrial equipment. As a result, procedures and instruments were developed that can detect, for example, toxic solvents at extremely low levels.
"We have technology that is very good for detecting the most minute amounts of hazardous materials," says Burastero. "The technology for measuring musculoskeletal risk is very crude in comparison. At Lawrence Livermore, we rarely see people inhaling toxic materials, but, as at worksites everywhere, we see musculoskeletal injuries among computer users."
Experts say preventing WRMSDs begins with ergonomics, a relatively new field concerned with studying the interaction between individuals and their working environment to ensure that tasks are performed safely and efficiently. Burastero contends, however, that all too often, products labeled ergonomic are not backed by data gained from rigorous research or extensive field trials. As a result, there's a surprising lack of knowledge on how injuries can be prevented.
In response to the lack of scientific data, Lawrence Livermore's Interdisciplinary Ergonomics Research Program is addressing comprehensively the problem of WRMSDs plaguing U.S. industry. The program uses a multidisciplinary research team that taps LLNL's strengths in human factors design and engineering, computational modeling, biomechanical engineering, sensors, industrial hygiene, and occupational medicine.
These strengths make it appropriate for Lawrence Livermore to tackle a pressing national problem such as WRMSDs, says Burastero. The LLNL work is funded by Livermore's Laboratory Directed Research and Development, the Department of Energy, and the computer industry. The research projects have attracted collaborators from the University of California's San Francisco School of Medicine, UC Berkeley, the National Institute of Occupational Health in Sweden, and the University of Michigan.
The research is also closely aligned with the Laboratory's Center for Healthcare Technologies and an internal ergonomics program. The latter is an employee-oriented research program that aims to reduce the severity of ergonomic injuries and illnesses at the Laboratory and to reduce the lost and restricted time attributed to these injuries.

Unique Resources at LLNL
Livermore's ergonomics research program draws upon a combination of four resources, which together exist nowhere else in the national laboratory family. The first is an ergonomics laboratory (see photo below) that is outfitted with state-of-the-art three-dimensional motion-analysis equipment that is used to study dynamic wrist motion, a sensor-based hand tracking system, an image processing lab, and a variety of ergonomic assessment equipment. Much of the equipment can be transported to an employee's worksite for "real-world" analysis of how people interact with their computers.

The ergonomics lab works closely with computational modeling experts in LLNL's Institute for Scientific Computing Research. This modeling capability, the program's second significant resource, is being applied to the study of human-machine interactions. For example, ergonomics laboratory data help validate the work of LLNL bioengineer Karin Hollerbach, who is developing a dynamic computational model of the bones and joints that are often associated with these injuries. (See September 1996 S&TR, pp. 19-21).
Biomedical engineer Robert Van Vorhis, who coordinates the ergonomics lab, also heads the technical aspects of a project to enhance a physician's visualization during endoscopic surgery for carpal tunnel syndrome. Improvements in endoscopic surgery could improve the cure rate of this minimally invasive surgical procedure such that, when it is successful, employees return to work in two weeks instead of six. This project is also leveraging Livermore's capabilities in optics and digital imaging with spinoff applications in advanced manufacturing.
The ergonomics research program's third major resource is Health Services' occupational health clinic (see photo at top), which has expertise in the diagnosis, treatment, and rehabilitation of WRMSDs. Livermore physicians and nurse practitioners diagnose and manage problems while physical therapists administer on-site treatment.
Finally, LLNL's large, stable, and innovative workforce provides excellent subjects for testing new products in the workplace and for providing valuable feedback. "We are a mini-town, with every profession represented, including editors, administrators, accountants, computer scientists, physicists, technicians, and engineers," says Burastero. All use computers differently, and most, he adds, are not shy about voicing their ideas and problems concerning computer usage.
With these four resources--laboratory, computer modeling, clinic, and employees--Livermore is providing a better picture of how these injuries are initiated and prevented and the role that computer accessories play in prevention and cure. Burastero says combining data from laboratory studies, workplace observation, long-term subject feedback, and expert medical monitoring is much preferable to other methods that consist solely of testing people in a controlled setting for a few hours or lending them a product to try.
Much of the research program's focus has been studying recent alternatives to standard computer keyboards. Conventional keyboards have been suspected of causing or exacerbating WRMSDs because their design can encourage use with wrists bent into awkward postures. Burastero notes that keyboards really have not changed much during the past 30 years--witness the host of "vestigial keys" such as "scroll lock" that date from the PC's earliest days.
Pat Tittiranonda, an ergonomist with the program, recently completed the most comprehensive computer-keyboard study ever performed. The three-year study involved 80 participants representing a broad range of occupations at Livermore. All had suffered WRMSDs such as carpal-tunnel syndrome or tendonitis. The volunteers were given one of four alternate keyboards to use for six months. The keyboards had been developed and marketed by different companies with the goals of increasing user comfort and reducing the risks of awkward wrist postures.
Over a period of six months, the research team closely analyzed how the subjects used their keyboards, including how much force they exerted on the keys with their fingers. The team also did video and three-dimensional motion analysis of the volunteers working at their computers. The results showed for the first time that keyboards specifically designed to lessen pressure on wrists can relieve the symptoms of WRMSDs and promote recovery. What's more, many of the alternative keyboards did not impair productivity and were relatively easy to learn.
The test subjects also completed a questionnaire on supervisor and coworker support and conflict. The data affirmed preliminary findings that the effectiveness of ergonomic interventions can be reduced in a stressful working situation.
The study, says Burastero, should have a "significant impact" by changing the way keyboards are designed and providing safety and health professionals with a greater understanding of the role of keyboards in WRMSDs. "There had been a lot of anecdotal evidence, but until now no one had systematically looked at how people actually work with keyboards or at the long-term effects," he says.
Livermore ergonomics experts caution that keyboards are only one factor associated with WRMSDs. For example, chairs, desks, terminals, and lighting conditions also play roles. So do pointing devices such as mice and trackballs, which the research team is planning to investigate in depth. At the very least, says Burastero, Lawrence Livermore can provide a knowledgeable perspective to manufacturers, clinicians, and workers everywhere.

--Arnie Heller

Key Words: carpal tunnel syndrome, ergonomics, industrial health, work-related musculoskeletal disorders (WRMSDs).

For further information contact Stephen Burastero (510) 424-4506 (

Back to March 1997