The severity of injury associated with sport concussions that present with a loss of consciousness or impact seizures is ambiguous. A disconnect between the clinical and biomechanical aspect can be observed throughout the literature pertaining to loss of consciousness and impact seizures. Clinicians have dismissed a loss of consciousness or the presence of impact seizures as an indicator of severity. However, early biomechanical research suggests that loss of consciousness is caused by greater magnitudes of impacts and damage to more vulnerable brain regions. However, this research was conducted on animal and cadaver models and may not adequately represent sport-related concussions. Recent methodologies such as laboratory reconstructions of head impacts and finite element modeling can provide new information on the severity of impact associated with these signs of concussions.
Study One compared the magnitudes of head dynamic response and brain tissue deformation between impact representations of punches that lead or do not lead to LOC in boxing. The main findings of this study revealed knockout punches were the result of by unprotected hooks to the mandibular angle resulting in greater brain tissue trauma.
Study Two compared cases of concussions with and without LOC in American football. Head dynamic response and brain tissue deformation was also greater in the LOC group in this sport, consistent with boxing impacts. The main predictor of LOC was found to be impact velocity which has implications in terms of prevention.
Study Three compared the magnitudes of head dynamic response and brain tissue deformation between cases of concussions with a loss of consciousness and cases of concussion with impact seizures in American football. The two types of clinical presentations had similar severities of brain tissue deformation with the exception of strain rate in the white matter being smaller in cases of impact seizures.
The findings of this thesis support the notion that concussions with loss of consciousness or impact seizure represent a more severe injury than concussions without these signs. It may be appropriate to address these signs of injury differently in return to sport protocols to reflect their severity. The findings also suggests that prevention of loss of consciousness should be sport specific. Hooks to the side of the jaw were the primary cause in boxing, whereas LOC could be caused by different event types in American football. However, in both sports, impact velocity and impact location played an important role in the risk for loss of consciousness.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/38632 |
| Date | 03 January 2019 |
| Creators | Cournoyer, Janie |
| Contributors | Hoshizaki, Thomas |
| Publisher | Université d'Ottawa / University of Ottawa |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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