Vibration absorbing brace for study of work-related upper extremity musculoskeletal disorders.

The use of hand-held power tools can result in absorption of significant vibration energy by the worker's hand and arm, and is a causal factor in the development of various muskuloskeletal disorders (MSD's) such as carpal tunnel syndrome (CTS) and hand-arm vibration syndrome (HAYS). A novel brace incorporating vibration damping materials is proposed that could reduce this energy absorption, resulting in lower incidence of vibration-related occupational MSD's. The National Occupational Research Agenda (NORA) has identified this type of injury as a priority research area. The proposed brace will have utility in the top three NORA-sponsored areas for research tools and approaches: clinical assessment of exposure to environmental vibration; practical use as improved personal protective gear; and evaluating the effects of reduced vibration exposure on MSD incidence. Clinical test results for prototype braces on human volunteers are reported: splints with piezoelectric material showed a median improvement of 12% in vibration damping as compared to otherwise identical nonpiezoelectric splints (median allowable error of +/- 1.5%). The use of these splints to further study how the hand-arm system absorbs vibration energy is also discussed.