The stability of equal sensation contours for whole-body vibration.

Using the modified matching procedure described by Oborne and Humphreys (1976), individual equal sensation contours for frequency range 3-80 Hz were obtained from twenty subjects. Each subject provided two sets of contours, the second set being obtained after an elapsed time period (between 1 and 66 days). In each case the curves obtained on the two occasions were extremely similar in shape, indicating the stability of individual response to vibration over time. Similar to that described by Oborne and Humphreys (1976), however, considerable variability existed between individual subject's contours. After suitable analysis, individual curves could be grouped according to the percentage of linear and quadratic components which They contained and, when the average contours obtained from each group were compared, the possibility of important differences in individual reaction to vibration were highlighted.