Sub-concussive trauma, acute concussion, and history of multiple concussions: Effects on quiet stance postural control stability.

Although balance control has been studied extensively following acute concussion, little is known regarding repetitive sub-concussive head impacts or chronic exposure to multiple concussive events. Quiet stance postural control was characterized in contact sport athletes at pre-season (n = 135) and post-season (n = 48) to evaluate the effects of subconcussive trauma to the head. To determine the impact of acute concussion on postural control, athletes diagnosed with a concussion during the season (n = 12) were tested at 72-h, 2-weeks, and 1-month post-injury. Because only 4 of the concussed athletes completed baseline testing, control athletes (n = 12) matched for sport, age, body mass index (BMI), and previous concussion history served as a comparison group. Finally, the effects of previous concussion history on quiet stance postural control were determined by comparing pre-season data in contact sport athletes with either zero (Hx0, n = 50) or three or more (Hx3+, n = 25) previous concussions. A force plate was used to compare changes in centre-of-pressure root-mean-square displacement (RMSdisp) and mean-velocity (COPvel) in the anterior/posterior (AP) and medial/lateral (ML) directions. One-minute trials were performed with feet hip-width apart, hands-on-hips, and A) eyes-open and B) eyes-closed. Biomechanical head-impact exposure (impacts over 10 g) was indexed over the season using mastoid-fixed impact sensors. In acutely injured athletes, repeated-measures ANOVA revealed a significant effect of time for RMSdisp AP with increased displacement at 2 weeks compared to 72 h (p = 0.008, 95% CI: -0.180, -0.310 cm). No other COP variables were affected by acute concussion. Moreover, there was no effect of concussion history or repeated sub-concussive impacts on any quiet stance metric. Additionally, head-impact exposure metrics were not correlated with COP metrics. Taken together, the data suggests alterations in COP sway during quiet stance persist in the acute 2-week period after injury. These findings were not present with either a history of multiple concussions or exposure to sub-concussive head impacts indicating acute concussion does not have appear to have long term effects for these measures.

Behavioral effects of prenatal versus postnatal androgen excess in children with 21-hydroxylase-deficient congenital adrenal hyperplasia.

Systematic behavioral studies show that females with congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH) are masculinized and defeminized in several ways; compared to their sisters, they play more with boys' toys, are more likely to use aggression when provoked, and show less interest in infants. We studied the extent to which these behavioral changes could be attributed to high levels of androgens in the prenatal vs. postnatal periods in 23 girls with CAH, aged 3-12 yr. Sex-atypical behavior was significantly associated with degree of inferred prenatal, but not postnatal, androgen excess; marked boy-typical play was associated with severe salt-wasting CAH, early age at diagnosis, and moderate genital masculinization at birth, but not with bone age advance, concurrent or cumulative high levels of 17-hydroxyprogesterone, or accelerated growth velocity in early childhood. Aggression and interest in infants were not consistently associated with indicators of prenatal or postnatal androgen excess, probably because those behaviors were measured less reliably than was toy play. The results are consistent with the idea that behavioral masculinization in girls with CAH results from high levels of androgens during fetal development and not in postnatal life.