Unveiling human vulnerability and a new interspecies scaling law for brain injury under blast loading

The common belief that animals with larger heads are more tolerated to brain injury faces challenges under the extreme conditions of blast loading. Recent studies indicate that humans, who have notably larger heads than other species of similar body weight, exhibit a unique vulnerability. Integrating animal experimental data, advanced head modeling, and pressure propagation theories, this research elucidates the injury mechanisms across species as the blast wave transitions from the extremely hard skull to the extremely soft brain. We propose a new interspecies scaling law based on consistent peaks of intracranial pressure, rather than head size, to redefine the translation from animal exposure thresholds to human risk assessment. This shift in perspective underscores the imperative to comprehensively consider both head geometry and size in predicting tolerance to blast brain injury, moving beyond simplistic size-based comparisons. Our study's insights contribute significantly to redefining injury risk models and fostering innovative prevention strategies against blast-induced traumatic brain injury (bTBI).