TO THE EDITOR:
Letter to the Editor Regarding “A Comprehensive Review of Low-Speed Rear Impact Volunteer Studies and a Comparison to Real-World Outcomes” by Cormier et al
We take issue with Cormier et al,1 who recently compared injury outcomes between laboratory volunteers and occupants in real-world low-speed rear-end crashes (LSRECs) and then concluded that (i) volunteers do not under-report symptoms, and (ii) volunteers can be safely exposed to rear-end impacts up to 18 km/h without meaningful injury risk. First, despite the large sample, the volunteers were not randomly sampled from the general population,2 making inferences to real injury rates difficult. Second, the real-world crashes were extracted from a database that purposefully excludes many LSRECs and typically omits the delayed-onset symptoms and comorbidities common to many, but not all, whiplash injuries. Thus, neither their volunteer injury data nor their field injury data adequately represent the complex outcomes frequently reported in the exposed population. More worrying is their failure to cite actual prospective data from real-world crash-related injuries3 that instead show a small percentage of individuals suffer prolonged symptoms following LSRECs with speed changes above 6.5 km/h. This omission, combined with both a convenient redefinition of injury and a call for higher speed volunteer tests, diminishes the real risk of prolonged symptoms in both the actual exposed population and future volunteers.
1. Cormier J, Gwin L, Reinhart L, et al. A comprehensive review of low-speed rear impact volunteer studies and a comparison to real-world outcomes. Spine (Phila Pa 1976)
2. Freeman MD, Croft AC, Rossignol AM, et al. A review and methodologic critique of the literature refuting whiplash syndrome. Spine (Phila Pa 1976)
3. Krafft M, Kullgren A, Malm S, et al. Influence of crash severity of various whiplash injury symtoms - a study on real-life rear-end crashes with recorded crash pulses (Paper No. 05-0363). Proceedings of the 19th
International Technical Conference on the Enhanced Safety of Vehicles; June 6–9, 2005, Washington, DC; 2005.