Detection and outcome of mild traumatic brain injury in patients and sportsmen : persisting symptoms, disabilities and life satisfaction in relation to S-100B, NSE and cortisol

Abstract: Traumatic brain injuries are common (hospitalization incidence: 250-300 per 100.000 inhabitants/year) and a great majority of these injuries (80-85%) are classified as mild traumatic brain injury (MTBI/concussion). Many patients with MTBI (20-80%) suffer from subsequent persistent and often disabling symptoms. In previous studies serum levels of biochemical markers of brain tissue damage (S-100B and neuron-specific enolase, NSE) have been propounded to serve as predictors of persisting symptoms.In the present studies serum concentrations of S-100B, NSE and cortisol in acute phase and post-concussion symptoms, post-traumatic stress-related symptoms, disabilities and life satisfaction one year after the trauma, were investigated in 88 patients (53 men and 35 women) with MTBI. Serum concentrations of S-100B and NSE were also assessed in elite players (n=54) of typical contact sports (ice-hockey and soccer), which are known to be high risk activities with respect to head injury. Basketball players (n=18) were used as a control group. A majority of patients with MTBI showed higher serum concentrations of S-100B, NSE and cortisol on admission compared with a second blood sample obtained about 7 hours later (p<0.001 for all analyses). Sequelae were common one year after the injury. Postconcussion symptoms were encountered in 45 % of the patients, stress-related symptoms in 17 % and disabilities in 48 %, but only 3 patients (4 %) were on sick-leave on follow-up due to the head trauma. There was a statistically significant negative correlation between the total score of life satisfaction and the total score of disability (r= -0.514, p<0.001). Symptoms on admission (dizziness, nausea) and S-100B were statistically significantly associated with disabilities (p<0.024, multiple logistic regression analysis). Nausea on admission was also statistically significantly associated with life satisfaction (p=0.004). A statistically significant association was found only for S-100B with early (0-1 week postinjury, p=0.008) and only for cortisol with late (more than 52 weeks post-injury, p=0.022) post-traumatic stress-related symptoms. Concentrations of S-100B after game were statistically significantly increased in comparison with the levels before game (soccer, p<0.001; ice-hockey, p<0.001; basketball (p<0.001). Concentrations of NSE were only raised after soccer play (p<0.001). Increases in S-100-B (post-game minus pre-game values) were correlated to the number of jumps in basketball play (r=0.706, p=0.002). For soccer, increases in S-100B were correlated to the number of headers (r=0.428, p=0.02) and to the number of acceleration/deceleration events other than heading (r=0.453, p=0.02). The findings provide support for the idea that injury of brain tissue is involved in the genesis of persisting disabilities and long-term changes of life satisfaction in MTBI. Since S-100B increases in serum were correlated to the number of headers and since soccer play also increased serum levels of NSE (in contrast to ice hockey and basketball), it seems that heading may have an impact on brain tissue. The studies have also shown that ordinary playing of the team sports in question (i.e. soccer, ice hockey and basketball) increases S-100B serum concentrations, which has to be taken into consideration when S-100B is used for the detection of injury of brain tissue in sportsmen with acute/overt head trauma during sport practice. An analysis of the biochemical markers of brain damage (in particular S-100B) may be an additional source of valuable information in the management of patients and sportsmen with MTBI. S-100B also seems to be promising for the prediction of impairments and disabilities after MTBI.