Injury Proven At 4km/h Impact

Whiplash Associated Disorder (WAD) Proven At 4km/h

Despite the documentation of thresholds and injuries, debate still continues regarding injury and whiplash associated disorder (WAD) at lower speeds. Likewise, disregarding multiple research studies, there is still an unfounded correlation being made between the property damage and bodily injury. Regarding bodily injury, an important question that has been answered is: “What is the threshold of patient tolerance to whiplash type forces?”

This question was addressed in a study by Brault, Wheeler, Siegmund, and Brault (1998): “Clinical response of human subjects to rear-end automobile collisions.“ The authors found: “Approximately 29% and 38% of the subjects exposed to the 4 km/h and 8 km/h speed changes, respectively, experienced WAD symptoms, with cervical symptoms and headaches predominating. Objective clinical deficits consistent with WAD were measured in both men and women subjects at both 4 km/h and 8 km/h.” [note: 4km/h is approx 2.48 mph]

Other effects noted were limited cervical (neck) range of motion. They state,  “Analysis of the effect of the 4km/h impact severity on ROM measurements over time revealed that, at both postimpact examinations, subjects with and without symptoms had a significant decrease in cervical flexion, extension, retraction, and right lateral flexion, with left lateral flexion ROM approaching statistical significance…At the 8km/h impact severity, ROM values were significantly reduced immediately post impact for cervical flexion, right and left lateral flexion, right rotation, and retraction for both groups with and without symptoms”

The conclusion of the study states: “The empirical findings in this study contribute to establishing a causal relationship between rear-end collisions and clinical signs and symptoms.”