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Shaw Chiropractic Know Your Literature Throughout 1999 I was teaching a seminar series called ABeating the Expert=s Report@. The emphasis of the program was directed towards preparing non-scientists (attorneys and support staff) to review biomechanical expert=s reports and to determine if the opinions hold up to scientific standards. More important, to see if the opinions expressed are consistent with the existing medical/scientific literature. During the seminar I discussed the commonly used defense and plaintiff oriented papers. This newsletter will review the John R Brault et al study from the January 1998 issue of the Archives of Physical Medicine and Rehabilitation. The article was titled Clinical Response of Human Subjects to Rear-End Automobile Collisions. In this study, subjects were exposed to delta Vs (? V) of 2.5 MPH and 5 MPH. The 2.5 MPH ?V was used based upon a previous study by McConnell which reported no symptoms. Approximately 29% and 38% of individuals exposed to the rear-end impacts at these ? Vs experienced whiplash symptoms. The authors noted that the presence of symptoms with ? Vs as low as 2.5 MPH conflicts with all previously published accounts of low speed collisions on human subjects. The subjects selection for this study was interesting in that they limited the subjects to 20-40 years of age. The subject group had no history of soft tissue disease. Subjects with neck or back problems within the last three years were excluded and pre-test MRI found no significant lesions. Also interesting is the fact that head restraints were properly adjusted which is uncommon in real world crashes. The authors note that the most significant finding in their study was the post traumatic reduction in ranges of motion in the cervical spine. They state that this Asuggests a measurable clinical defect@ and was found at both 2.5 MPH and 5 MPH ? V groups. The clinical findings of the subjects were highly variable which Aattests to the non-specific effect of the whiplash injury mechanism@ This lends credence to the common finding that two individuals subject to the same injury mechanism may demonstrate quite different clinical findings. The following factors are known to increase the injury severity and were not necessarily controlled in the Brault study:
Subsequent to the Brault et al paper there have been other scientifically valid papers supporting the contention that lower velocity impacts have the capacity to cause injury. For more information about these papers or to schedule a seminar please contact us at 1-800-232-6824. |
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