A Study of Tissue Vibration Transmissibility Using a Scanning Laser Vibrometer

Prolonged exposure to vibration has been associated with the development of handarm vibration syndrome (HAVS). While vibration is known to have adverse physiological effects on the tissues of the human hand, it is still unclear how these physiological effects are influenced by factors such as tissue thickness or vibration intensity, frequency, and duration. Understanding the response of the hand to vibration may be helpful in determining the mechanisms behind the development of HAVS. Dynamic response of the hand and arm to vibration has been studied by several investigators (Abrams and Suggs, 1966, Burstrom, 1990). However, these studies have concentrated on the overall impedance of the hand/arm system or have looked only at the vibration transmitted along the bones or on the surface of the hand or arm. The vibration transmissibility through individual tissues such as skin, fat, muscle, blood vessels, and nerves has not been investigated because of the difficulty in making these measurements in vivo. Computer models of the hand have been proposed as a solution to this problem. By using finite element modeling techniques, each tissue can be modeled separately and the vibration transmissibility at different tissue depths can be calculated. However, for these models to be truly useful, validation is necessary. As a first approximation to validate these models, transmissibility in skeletal muscle and fat was measured as a function of the tissue depth using a scanning Doppler laser vibrometer. METHODS