How Concussions Incorrectly Date Your Dead Brain
Bang! The pain reverberates through your skull as you sluggishly move, recovering from the initial hit. However, the effects of your accident will stay with you longer than you think.
Common in injuries or sports, a concussion is a brain injury caused by head trauma [3]. Recent studies posit a confounding impact of concussions in Postmortem Interval (PMI) calculations, or time since death. The National Insitute of Justice sites PMI as critical for criminal and forensic investigations. Thus, it is paramount for these calculations to be accurate. [4]
Two studies recently published in the International Journal of Legal Medicine and Nature’s Scientific Reports observed the physiological changes to the lateral cerebral ventricle (LCV) postmortem [1][2]. The LCV is a brain cavity responsible for circulating cerebral fluid, which cushions the brain and spine from trauma.
The first study, led by Fabio De-Giorgo of Università Cattolica del Sacro Cuore, proposed using X-rays of the LCV to determine PMI [1]. A second study, led by Bailey Hiles-Murison of Curtin University, considered the inflammatory effects of concussions on the LCV [2]. The results of the two studies raise questions about how concussions may lead to incorrect PMI determinations in patients who have had brain injuries.
De-Giorgo’s research team studied 10 cadavers of various causes of death, age, and sex [1]. All observed cadavers lacked head injuries or diseases to ensure a baseline condition for comparison [1].
The researchers periodically took X-ray scans dissecting the LCV in each cadaver. They observed a proportional decrease in ventricle volume with increasing time since death [1]. The team also noted that older cadavers had larger initial cavities, hinting at age being a possible variable in PMI calculations [1]. The varying morphologies ultimately prevented the researchers from standardizing an inflammation reduction rate [1].
Unfortunately, the detrimental effects of concussions on the LCV complicate De-Giorgo’s method.
Hiles-Murison’s research team sought to model the impact of concussions on the LCV through mice [2]. Two groups of 8 mice were formed, a control and an experimental group [2]. Over two weeks, the experimental group underwent a concussion stimulation every three days [2].
Prior to each stimulation, the Hills-Murison team anesthetized the mice [2]. The researchers then successively dropped a 25-gram weight one meter above the mice’s heads a total of 10 times, pausing 10-20 seconds after every interval [2].
After two weeks, the concussions’ effects on the mice’s coordination were observed through a series of increasingly narrow balance beam tests [2]. Despite their injuries, the experimental group passed all the tests, seemingly not impaired by the trauma [2]. In fact, the researchers determined both groups successfully performed the test with similar ranges of error [2].
However, cross-sections of the experimental group’s brains revealed severe LCV inflammation. Despite their normal post-recovery behavior, the experimental group retained significant, permanent brain damage in the cross-section examinations [2]. The retention of damage raises significant concerns for athletes and others at high risk for head injuries.
The recovery rate from a concussion can vary across age groups and physiological health. This uncertainty prevents the usage of precedential data and lowers the accuracy of PMI calculations.
For example, a brain cavity inflamed by multiple concussions may falsely implicate an older individual, misinforming criminal investigators about the victim. This misinterpretation can detrimentally derail cases with limited identification information available.
Still, De-Giogro is hopeful about the future of using radiology in forensics.
“Forensic radiology a new discipline,” he discusses in his study. “We feel that a multiparametric and multiscale approach…that combin[es] different radiological techniques with findings from forensic medicine, pathology, physics, and biomechanics, would help to provide new insights into the complex problem of determining the postmortem interval” [1].
So, the next time you are playing a sport or taking part in a dangerous activity, watch your head! Every bump may add a couple more years.
About the Author: Grace Cheng
Grace Cheng is currently a fourth-year Biological Science major at UC Davis. While she plans to pursue medical school after her undergraduate degree, she is a firm believer in spreading scientific knowledge and research. Particularly, she has an interest in the medical and scientific processes that occur in the body post-mortem, fueling the creation of this article.
Author's Note
The purpose of this article is to publicize to a general audience two recent studies on the impacts of concussions as well as conflicts in determining Postmortem Intervals. I chose a supplemental study that is applicable to a lay audience, as concussions can occur from sports or accidents. I would like my audience to gain an appreciation of what the Postmortem Interval is, how it is obtained, and how incidents in our daily lives shape our bodies, before and after death.
References
De-Giorgio, F., Ciasca, G., Fecondo, G., Mazzini, A., Spirito, M. D., & Pascali, V. L. (2022, February 23). Estimation of the time of death by measuring the variation of lateral cerebral ventricle volume and cerebrospinal fluid radiodensity using postmortem computed tomography - International Journal of Legal Medicine. SpringerLink. https://link.springer.com/article/10.1007/s00414-021-02698-6
Hiles-Murison, B., Lavender, A. P., Hackett, M. J., Armstrong, J. J., Nesbit, M., Rawlings, S., McGonigle, T., Warnock, A., Lam, V., Mamo, J. C. L., Fitzgerald, M., & Takechi, R. (2021, April 29). Blood–brain barrier disruption and ventricular enlargement are the earliest neuropathological changes in rats with repeated sub-concussive impacts over 2 weeks. Scientific Reports. https://www.nature.com/articles/s41598-021-88854-9
“What Is a Concussion?” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 12 Feb. 2019, www.cdc.gov/headsup/basics/concussion_whatis.html.
- “Estimating the Postmortem Interval of Human Skeletal Remains Using Rapid, Inexpensive Microbiome Tools.” National Institute of Justice, National Institute of Justice, 2019, nij.ojp.gov/funding/awards/2019-du-bx-0010.