Can a more neutral position of the forearm when operating a computer mouse reduce the pain level for VDU operators?

A prospective epidemiological field study covering a 1-year period has been published (Int. J. Hum.-Comput. Interaction, 1999; 2001). The aim of the study was to investigate if subjects with existing musculoskeletal pain experience a reduction in pain development when using a new mouse design (Anir/Renaissance) which allows a more neutral position of the wrist, compared with a traditional mouse. The study population consisted of 67 participants with average intensity of pain during the last 6 months of approximately 50 mm on a 100 mm visual analog scale (VAS). The total group was randomly divided into one intervention group and one control group. The study was performed as a prospective parallel group design. VAS was used to assess the average level of pain in the musculoskeletal system during the last 6 months. This was a three-part study; the first two parts of which have already been reported. In part 1, it was found that after using Anir mouse for 6 months, there were significant reductions in pain for neck, shoulder, forearm, wrist and hand (Int. J. Hum.-Comput. Interaction 11(2) (1999) 79). The control group, using the traditional mouse reported no significant changes in the pain level. In part 11, The Anir mouse was given to the control group 6 months after the start of the study. After 6 months of using the Anir mouse, the former control group reported a significant reduction in pain for neck, shoulder, forearm, wrist and hand. The group getting the initial intervention reported still significant reductions of pain in the upper part of the body, 12 months after the start of the study (Int. J. Hum.-Comput. Interaction 13(l) (2001) 13). The present paper covers the period from I to 3 years of the study. By inspection of the mean values of pain over time, no relevant changes seem to have appeared in the period from 12 to 36 months. No significant changes in confounding factors were found during the period from 12 to 36 months. The results from this study indicate the importance of using a more neutral position of the forearm when using a computer mouse.