Concussion is a life-altering injury that can affect people of all ages. Event-related potentials (ERPs) extracted from electroencephalography (EEG) have proven sensitive to concussion-induced cognitive deficits. The MMN, P3a, P3b, and N2b are some ERP components of interest, assessing automatic attention, attentional resource allocation, working memory, and inhibitory executive function, respectively. These ERPs can assess some common symptoms associated with concussion at a level that cannot be attained using self-report. A reduced amplitude and potentially delayed latency of the P3a and P3b is a well-replicated result in concussion research. Furthermore, recent research suggests that an alteration in amplitude of earlier peaks such as the N2b and MMN might represent an irreversible change in cognitive processing that tends to occur in the chronic stages of concussion. Many of these studies have focused on athletes, however little research has evaluated the cognitive effects of sustaining numerous blows to the head that do not result in a clinical diagnosis of concussion, as is the case for many athletes in contact sports. These blows are often referred to as subconcussive impacts. The present study examined the cognitive and neurophysiological effects of subconcussive impacts on collegiate contact-sport athletes and compared them to noncontact athletes. The athletes completed questionnaires to evaluate their health and athletic history, as well as estimates of exposure to subconcussive impacts such as position and playing time, prior to participating in three paradigms meant to assess various cognitive processes during an EEG recording. Across two experiments we demonstrated that subconcussive impacts within a season of play can result in alterations in neurophysiological markers of cognitive health. Our findings also reveal that continued involvement in contact sports can have serious implications in one’s automatic attention, resource allocation, and working memory as demonstrated by reduced ERP amplitudes in contact as compared to non-contact athletes. / Thesis / Master of Science (MSc) / A concussion is a devastating injury that can greatly affect how an individual functions in their day-to-day life. Concussions are often discussed in the context of contact sports because of these athletes’ exposure to repeated head impacts. That said, another cause for concern is the effects of head impacts that do not result in a concussion per se – these are known as subconcussive impacts. A brain imaging technique known as electroencephalography (EEG) involves recording brain activity from sensors on the head. Conducting this recording while individuals perform tasks known to evaluate brain function offers an opportunity to assess symptoms rather than relying on a patient’s own, subjective report of their experiences. The present study investigated the use of EEG in evaluating the effects of subconcussive impacts in collegiate athletes and found that repeated head impacts can reduce cognitive health, even if they do not result in a diagnosis of concussion.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/25519 |
| Date | January 2020 |
| Creators | Ewers, Nathalee P. |
| Contributors | Connolly, John F., Psychology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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