Brussels, 13 May 2003
The latest word from Danish researchers is the more you click your mouse, the higher the chance of repetitive strain injuries (RSI) for workers and frequent computer users.
The dreaded RSI is back. Just writing an article like this could increase the chances of acquiring a repetitive strain injury in the hand, neck and shoulder, leading authorities from two Danish research centres told a scientific conference in Brazil earlier this year.
Scientists from the Odense University Hospital found that people using a mouse – the small device that controls the movement of the cursor or pointer on a computer's display screen – over 30 hours per week have up to eight times greater risk of developing pain in the lower arm, twice the chance of experiencing moderate to severe neck pain and three times the risk of shoulder pain.
The findings come from a survey of some 7 000 machine technicians and technical assistants, validated by a follow-up study one year later. Shoulder symptoms became evident after only five hours of weekly use, while neck problems showed after more than 25 hours of use. The research noted that certain professions face a higher risk of acquiring RSIs, such as "computer-assisted designers [who] use the mouse all the time".
A hugely popular device
Ever since Douglas Engelbart of Stanford Research Centre invented the mouse in 1963, and Xerox pioneered its use in the 1970s, it was destined for success – freeing computer operators to a large extent from using the keyboard. The mouse has become especially useful for graphics programs and software with graphical interfaces which allow the mouse to be used like a pen or paintbrush.
Now that computers are a standard feature of the working environment, the mouse has become far more popular, and potentially dangerous. Researchers at the National Institute of Occupational Health (NIOH) in Copenhagen found that workers using computers for over two-thirds of their work time had a greater risk of developing hand or wrist problems.
Workers who spent nearly all day at the computer, and used the mouse at least half of that time, had four times more risk of associated RSI problems than those who used alternatives to the mouse a quarter of the time. The results come from a study of almost 3 500 workers in 11 Danish firms, with a follow-up about 18 months later.
From an occupational health perspective, the problem is not just using the mouse, but performing repetitive tasks, Dr Chris Jensen of NIOH told reporters at the th International Congress of Occupational Health. He recommended that people should vary the pattern of use between the keyboard and mouse. This is arguably the best solution for people who cannot reduce their time spent at the computer.