A slightly different version of this study is published in TRL Journal of Research 1999, Volume 2, No 1, 1999, pp1-11, and for the abstract see ITRD E102122 or text following. A sample of 174 road accident victims suffering from Whiplash Associated Disorder were studied over a two year period. The vehicles they had been travelling in were examined to assess the impact severity and, where possible, measurements were made of seat and head restraint adjustment with the subject sitting in the vehicle. Each subject was interviewed to assess the disability resulting from their injuries, and their progress was followed up for twelve months. Women suffered significantly greater disability than men, but there was no correlation with occupant age, height or weight. The benefit of having a head restraint fitted could not be consistently demonstrated. The overall sample also showed no correlation between disability and vertical restraint adjustment, awareness of impending impact or impact speed. Comparison of impact directions produced inconsistent results. Horizontal distance from head to restraint had no effect on initial disability scores but, for long-term outcome, small horizontal distance was significantly associated with higher disability, contrary to the received wisdom. A significant proportion of the sample had suffered lumbar strain injury in addition to whiplash, but segregation of the sample by lumbar injury status failed to give a clearer picture. Seat back angle had a significant effect on the lumbar injury cases, but was not important for non-lumbar cases. It is concluded that variations in restraint, seat and vehicle structural design are likely to have swamped the expected variations due to individual restraint adjustment. (A)
Abstract