Show Notes for Podcast Seven of seX & whY, Part 1
Thank you for Alyson McGregor for correctly pointing out that although the NIH, as of January 2016, does require its basic scientists to include both males and female animals in their grant proposals it is not called the “Research for All Act”. The Research for All Act of 2014 is actually a bill sponsored by Congressman Jim Cooper of Tennessee that would require, among other things, that the FDA have access to subgroup analysis of data by sex prior to granting expedited approval of a new product. As of now, this bill has not passed.
Host: Jeannette Wolfe
Dr. Neha Raukar, Emergency and Sports Medicine Physician
Katherine Snedaker, Executive Director of Pink Concussions
Topic: Sex and Gender Differences in Concussions
Take home points
- The research behind traumatic brain injury is rapidly evolving as technology advances are allowing us to better understand how the human brain works and the nuances between male and female brains
- We still have a long way to go because most of the basic science surrounding traumatic brain injury has been conducted on male animals
- In 2015 the NIH passed The Research for All Act that requires NIH funded basic science to include both male and female animals or be able to justify their exclusion
- Men, compared to women, have an overall greater incidence of traumatic brain injury and this is likely associated with differences in risk tolerance and exposure to activities associated with potential injury
- In situations in which risk exposure is the same- like playing basketball or soccer- after sustaining the same impact, women appear to have a lower neurobiological threshold to obtain a traumatic brain injury than men
- Definitive/proportionate reasons for these differences are not fully understood, however possible factors include:
- Weaker neck muscles
- Decreased neurobiological threshold for injury
- Hormonal differences
- Reporting bias- this theory is quite controversial and it was emphasized throughout the podcast that many athletes, especially at elite levels- will underreport symptoms regardless of their biological sex
- Hormonal influences- it appears that a woman’s vulnerability to traumatic brain injury may vary depending upon where she is within her menstrual cycle (with injury during the luteal phase leading to increased concussive symptoms) or whether or not she is on oral contraceptives (with some evidence that women on OCPs having decreased symptoms).
- Symptoms of concussion can be broken down into different categories:
- Cognitive- issues with memory/concentration/fogginess
- Emotional- anxiety, irritability/sadness
- Somatic- headaches/ light noise sensitivity/nausea and vomiting
- Vesitibular/Ocular- balance, eye tracking
Collins, C.L., Fletcher, E.N., Fields, S.K. et al. Neck Strength: A Protective Factor Reducing Risk for Concussion in High School Sports J Primary Prevent (2014) 35: 309. https://doi-org.ezproxy.library.tufts.edu/10.1007/s10935-014-0355-2
Covassin T, Moran R, Elbin RJ. Sex differences in reported concussion injury rates and time loss from participation: an update of the National Collegiate Athletic Association Injury Surveillance Program from 2004-2005 through 2008-2009. J Athl Train. 2016;51:189-194.
Wilcox, B. J., Beckwith, J. G., Greenwald, R. M., Raukar, N. P., Chu, J. J., McAllister, T. W., … Crisco, J. J. (2015). Biomechanics of head impacts associated with diagnosed concussion in female collegiate ice hockey players. Journal of Biomechanics, 48(10), 2201–2204.
Wunderle K, Hoeger KM, Wasserman E, Bazarian JJ. Menstrual phase as predictor of outcome after mild traumatic brain injury in women. J Head Trauma Rehabil. 2014;29: