BLOG: TBI experience, recovery different in women, men
Most studies on traumatic brain injury, particularly when it comes to military populations and blast injuries, have enrolled men, either primarily or exclusively.
It is not unusual to find papers on traumatic brain injury (TBI) in which only 5% or 1% of the study cohort was female, with no attempt to analyze whether there were any differences in that small percentage of women relative to the group as a whole.
Without more information, we may be making flawed inferences about women’s experience of and recovery from TBI. Our treatment strategies, whether rehabilitative care or emergency neurosurgical procedures, are therefore much less evidence-based when applied to female patients than to males.
A few years ago, my colleagues and I conducted a review of the literature to determine what is known thus far about differences by sex in TBI (Kim et al.) We found that depression was a more prevalent comorbidity in women than in men. Additionally, women were dramatically more likely than men to report somatosensory deficits, including vision-related vestibular, oculomotor and proprioceptive problems.
Much more work is needed to understand the nuances behind these findings. In particular, we need larger retrospective data sets that include more women, as well as prospective data acquisition by gender that evaluates both brain structure and function.
My neuroscientist colleague Maheen Adamson, PhD, has been looking for surrogate markers in the brain that can help us understand the relationship between brain structure and functional changes after TBI. Cortical thickness is one such potential marker that is frequently used in neuro-imaging studies of neurological disease progression, but we don’t yet know how reliable it is in following acquired brain injuries like a TBI.
In healthy brains, there are gender-based differences in this marker: Women have about 6% thicker brain cortex than men. After a TBI, both men and women experience thinning of the cortex, but imaging studies suggest that female veterans had more severe cortical thinning than their male counterparts.
Ideally, we want to be able to see how these physiological changes in the brain correlate with patients’ symptoms and functional outcomes. We are still in the very early stages of this work, but it holds promise for better understanding and predicting response to treatment.
This work could be applied to other subpopulations besides women – to older or younger patients or to specific types of injuries, for example. It is not that the literature on TBI is untrue, it’s just that it is not nuanced enough for us to provide the most accurate care.
I am excited that many different specialties are beginning to notice and address this problem. Given the ongoing efforts, I am optimistic that we can develop a more complete picture of how women’s brains and brain function are affected by TBI so that we can truly practice evidence-based neurosurgery and brain injury rehabilitation.
- Kim LH, et al. Neurosurg Focus. 2018;doi:10.3171/2018.9.FOCUS18369.
For more information:
Odette Harris MD, MPH, is professor of neurosurgery and director of brain injury at Stanford University School of Medicine. She is also the deputy chief of staff for rehabilitation at Veterans Administration Palo Alto Health Care System and the site director, Traumatic Brain Injury Center of Excellence. Harris focuses on collaborative approaches in implementing and streamlining algorithms aimed at improving outcomes in neurosurgical care. She is the recipient of a National Medical Fellowship for excellence in academic medicine and has received many other awards for her clinical and research work. She is a former president of Women in Neurosurgery and director of the California Association of Neurological Surgeons.
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