Are there cognitive and neurobehavioural correlates of hormonal neuroprotection for women after TBI?

Abstract

This study examined possible cognitive correlates of hormonal neuroprotection following traumatic brain injury (TBI) using archival neuropsychological findings for 1563 individuals undergoing acute TBI rehabilitation between 1989 and 2002. Presumed age of menopause was based on the STRAW (Stages of Reproductive Aging) staging system (Soules, 2005; Soules et al., 2001) and general linear model (GLM) analysis of performance on neuropsychological testing by participants across gender and age groups (25-34, 35-44, 45-54, and 55-64) was performed. Hypotheses were (1) women with TBI in the oldest age group would have lower scores on neuropsychological tests and functional outcome measures than women in the younger groups, and (2) men in the oldest age group would have higher scores than women of the same age group. Analyses revealed that oldest females had significantly worse Trails B and SDMT written and oral scores than the youngest females. In addition, oldest females had significantly better Trails B, Rey AVLT and SDMT written scores than the oldest males. Possible cohort exposure to hormone replacement therapy, unknown hormonal status at time of testing, and sample-specific injury characteristics may have contributed to these findings.

Gender Differences in Awareness and Outcomes During Acute Traumatic Brain Injury Recovery

“…31,46,47 Overall, each approach to the study of hormone-related gender advantage for women following TBI has, much the same as the study of gender differences in post-TBI outcomes, yielded mixed results. 45 The finding that women with TBI in our study sample were able to appraise their injury-related impairments more accurately than men at discharge is similar to prior evidence 1,3 of superior postinjury executive functions for females. Researchers examining the role of reproductive hormones in TBI recovery might argue that the difference can be accounted for, in part, by hormonal neuroprotection related to higher levels of progesterone.…”

“…First, a preliminary explanation of the results finds a certain degree of support in recent research into hormonal neuroprotection. [45][46][47] Hormonal neuroprotection is often proposed as an underlying mechanism 4,[48][49][50][51][52][53][54][55][56][57] in what the TBI literature collectively suggests is a gender advantage in postinjury recovery. Although typically higher in women, progesterone is produced by neurons and glial cells in the central and peripheral nervous systems by both men and women and has become a frequent target in efficacy trials.…”

“…Researchers examining the role of reproductive hormones in TBI recovery might argue that the difference can be accounted for, in part, by hormonal neuroprotection related to higher levels of progesterone. 45,[48][49][50][51] However, blood samples indicating levels of hormones for female study participants were not drawn or analyzed. Future studies may want to add assays of blood levels of reproductive hormones as a variable of interest.…”

A systematic review of age and gender factors in prolonged post-concussion symptoms after mild head injury

“…There is evidence that in severe head injuries a degree of neuroprotection may be afforded by some of the female sex hormones, particularly progesterone [19]. The data in this area, however, are by no means consistent and some studies have demonstrated better neuropsychological outcome in women, while others have shown better functional outcome in men [19].…”

A Repeated Measures Pilot Comparison of Trajectories of Fluctuating Endogenous Hormones in Young Women with Traumatic Brain Injury, Healthy Controls

“…Based on this work, equal numbers report women and men recover better than the opposite sex after TBI, and still others report no sex differences in recovery. Neuropsychological test performance studies show adult women outperforming men in executive functions, as well as verbal and visual memory after TBI [7, 8, 20–22]. However, these reported sex differences partially reflect well-documented sex differences in innate abilities of healthy children and adults [23–25].…”