Concussion management is changing. Recent years have marked a sea change, with the former rest-is-best approach being supplanted by an exercise-is-medicine mindset. Despite this, important questions remain unanswered in the pediatric exercise-concussion literature. The overarching aim of this thesis was to examine the effects of exercise on outcomes beyond concussion symptoms, and build our understanding of the relationship between pediatric concussion and physical activity.
Four studies were performed to this end. First, per a systematic review, we found that randomized trials on the effects of exercise on neuroimaging and cognitive outcomes remain limited. Studies suggest that exercise may improve brain structure and function post-concussion, while data with respect to cognitive outcome were mixed. Second, we provided the first evidence that the functional neuropathology of pediatric concussion differs by sex at 1 month post-injury, with females demonstrating impairment not observed in males. Namely, only females with concussion showed patterns of both hyper-connectivity (between the lateral pre-frontal cortex & inferior frontal gyrus, lateral pre-frontal cortex & lateral occipital cortex, and the posterior cingulate cortex & cerebellum; all p-corrected <0.05) and hypo-connectivity (between the anterior cingulate cortex & precuneus, anterior cingulate cortex & cingulate gyrus, and posterior cingulate cortex & paracingulate gyrus; all p-corrected <0.05). Third, we provided the first accelerometer-based characterization of physical activity and sedentary time in children with concussion in comparison to 1:1 matched healthy controls. Relative to healthy controls, children with concussion were more sedentary, with a mean difference [MD] of 38.3 minutes/day (95% confidence interval [CI] 11.2 to 65.4, p<0.01), and they also performed less light (MD -19.5 minutes/day, CI -5.3 to -33.7, p<0.01), moderate (MD -9.8 minutes/day, CI -5.7 to -13.8, p<0.001) and vigorous physical activity (MD -12.0, CI -6.9 to -17.2, p<0.001); greater physical activity deficits were observed in females with concussion. Fourth, per the first study to employ both accelerometry and functional neuroimaging in pediatric concussion, we found that intra-network connectivity of the default mode network was associated with subsequent accelerometer-measured light (F(2, 11) = 7.053, p = 0.011, Ra2 = 0.562; β = 0.469), moderate (F(2, 11) = 6.159, p = 0.016, Ra2 = 0.528; β = 0.725), and vigorous (F(2, 11) = 10.855, p = 0.002, Ra2 = 0.664; β = 0.792) physical activity. This study provides the insight into a potential link between brain activity and physical activity in pediatric concussion. The next wave of exercise and physical activity research in concussion needs to move beyond symptom studies, employ sex-specific analyses, understand the impact of exercise on brain function, and consider interventions that increase habitual physical activity. Doing so is necessary for exercise to become medicine for concussion patients. / Thesis / Doctor of Philosophy (PhD) / Until a few years ago, the advice children received after a concussion (or mild brain injury) was to rest until they no longer had symptoms. But the way concussions are being treated is changing. Scientists have found that exercising soon after a concussion can lessen symptoms. It is no longer thought that rest-is-best. Instead, it is now believed that exercise-is-medicine. But there are still important questions about the role of exercise after a concussion that have not been answered. The four studies in this thesis had the goal of answering some of those questions. In the first study, we found that while exercise improves symptoms after a concussion, we know less about how it impacts the brain and our ability to think. From the second study, we learned that a concussion impacts the brains of boys and girls in different ways, and that girls may have longer lasting brain changes after a concussion than boys. Our third study showed that after a concussion, girls take part in less physical activity than boys throughout the day. The fourth study suggests that there may be a link between brain activity and physical activity in children with a concussion. This thesis adds to our knowledge of the role of exercise in concussion. It also raises some important questions that should be answered by new studies in the near future.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/26884 |
| Date | January 2021 |
| Creators | Sharma, Bhanu |
| Contributors | Timmons, Brian W, Medical Sciences |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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