Sports neurology topics in neurologic practice: A survey of AAN members.

We sought to assess neurologists' interest in sports neurology and learn about their experience in treating sports-related neurologic conditions. A survey was sent to a random sample of American Academy of Neurology members. A majority of members (77%) see at least some patients with sports-related neurologic issues. Concussion is the most common sports-related condition neurologists treat. More than half of survey participants (63%) did not receive any formal or informal training in sports neurology. At least two-thirds of respondents think it is very important to address the following issues: developing evidence-based return-to-play guidelines, identifying risk factors for long-term cognitive-behavioral sequelae, and developing objective diagnostic criteria for concussion. Our findings provide an up-to-date view of the subspecialty of sports neurology and identify areas for future research.

Estimation of head impact exposure in high school football: implications for regulating contact practices.

BACKGROUND: Increased attention is being placed on the role of subconcussive impacts to the head during football participation and long-term cognitive health. Some have suggested that mitigating impacts to the head can be achieved by reducing or eliminating contact football practices. The effect that this might have on the number and magnitude of impacts is unknown. PURPOSE: To estimate the effect of limiting contact practices on the frequency and magnitude of head impacts through the retrospective assessment of in vivo head impact data. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Data on impact magnitude and frequency were collected with the Head Impact Telemetry System during the 2009 football season among 42 varsity high school football athletes (mean age, 16.2 ± 0.6 years; mean height, 180.9 ± 7.2 cm; mean weight, 89.8 ± 20.1 kg). Head impacts were compared between player positions and session types (noncontact practice, contact practice, and game). These results were used to estimate the frequency and magnitude of head impacts when contact sessions were restricted. RESULTS: The participants collectively sustained 32,510 impacts over the 15-week season. The typical athlete sustained a mean of 774 ± 502 impacts during the season, with linemen (center, guard, and offensive or defensive tackle positions) sustaining the highest number of impacts per athlete (1076 ± 541), followed by tight ends, running backs, and linebackers (779 ± 286); wide receivers, cornerbacks, and safeties (417 ± 266); and quarterbacks (356 ± 433). When viewed by session type, noncontact practices (n = 21) accounted for 1998 total impacts (2.4 ± 1.4 per athlete per session), contact practices (n = 36) accounted for 16,346 impacts (10.5 ± 7.7 per athlete per session), and games (n = 14) accounted for 14,166 impacts (24.1 ± 19.1 per athlete per session). Significantly more impacts occurred during games when compared with contact (P = .02) and noncontact practices (P < .001), and contact practices yielded significantly more impacts than noncontact practices (P = .02). Limiting contact practices to once per week would result in a 18% reduction in impacts for the duration of a season, while eliminating all contact practices would further reduce seasonal impacts by 39% across all players. Impact magnitudes were significantly highest during game sessions compared with contact and noncontact practices. CONCLUSION: Our findings suggest that limiting or eliminating contact football practices may reduce the number of head impacts sustained by athletes over the course of a season, although the effect that such rule changes may have on the magnitude of head impacts during practice sessions is less clear. As such, the potential effect of reductions in contact practices on athletes' long-term cerebral health remains unknown.

Field-based measures of head impacts in high school football athletes.

PURPOSE OF REVIEW: Recent technological advances have allowed the in-vivo measurement of impacts sustained to the head during helmeted sports. These measurements are of interest to researchers and clinicians for their potential to understand both the underlying mechanics of concussive injuries and the potential for real-time injury diagnostics. Following an overview of impact biomechanics, this review will evaluate the following: in-vivo technology being used in American football players; impact frequencies and magnitudes; and the biomechanical threshold for concussion. RECENT FINDINGS: The average high school athlete sustains over 650 impacts in a season, and the level at which concussion occurs is approximately 100  g and 5500  rad/s/s. SUMMARY: High school athletes sustain a significant number of head impacts each year. The impacts are similar in both volume and magnitude when compared with collegiate athletes. The magnitude of impact that results in concussion is also the same at both levels of play, although the collegiate athlete may have a higher injury tolerance.

Cognitive decline and aging: the role of concussive and subconcussive impacts.

Concussion has been viewed historically as a transient injury with no evidence supporting the existence of persistent effects. However, our recent work demonstrates electroencephalographic and motor control changes in otherwise healthy individuals with a history of concussion. We therefore hypothesize that concussive and subconcussive head impacts set about a cascade of pathological events that accelerates declines in cognitive function typically associated with the aging process.