Resumen de Ejercicio físico y cognición: mecanismos de acción y evaluación del valor terapéutico potencial en traumatismo craneoencefálico
The following thesis covers the growing and pertinent topic of the therapeutic use of aerobic physical exercise in cognitive function following traumatic brain injury. Various experimental methodologies are employed to globally assess the role of physical exercise in cognitive recovery following traumatic brain injury. The squeal of cognitive dysfunction after a traumatic brain injury can be devastating and affect personal, social and economic aspects of one’s life. Many animal models of traumatic brain injury suggest physical exercise can have both neuroprotective and neurorestorative effects following injury. This thesis aimed to gain an up-to-date understanding of the extant literature regarding the use of physical exercise in cognitive recovery following traumatic brain injury in humans. The first experimental chapter of the thesis found that few (6) studies have researched this topic with varying degrees of methodological quality. Consequently, the second experimental chapter aimed to assess the feasibility of introducing a dedicated 8-week program of aerobic physical exercise into the sub-acute phase of recovery form moderate-to-severe traumatic brain injury, in addition to standard multidisciplinary rehabilitation. Although the feasibility of this program was demonstrated, certain complications regarding the intensity of exercise and how to control for it were noted. Specifically, few of the participants were capable of exercise at higher exercise intensities. In response, the third experimental chapter aimed to gain an mechanistic understanding of the biological underpinnings of physical exercise’s effect on cognitive function, specifically that of light intensity exercise, an intensity proposed to be more achievable to those with physical complications secondary to a traumatic brain injury. The study used transcranial magnetic stimulation to measure short-term changes in cortical neuroplasticity as well as measuring peripheral levels of Insulin-like growth factor-1, a neurotrophin implicated in synaptic plasticity and recovery from traumatic brain injury. Results found that spatial working memory and cortical inhibition appear to be modulated by a single bout of light aerobic exercise in those with a mild traumatic brain injury. Whilst the aforementioned chapters discussed the use of physical exercise earlier after injury, the cognitive deficits can persist for decades post-injury. As such, the final experimental chapter assessed the relationship between physical activity levels and global and cognitive health in community-dwelling adults with a history of traumatic brain injury. The results demonstrated that those who were active (compared to insufficiently active) were around 3 times as likely to report good global and cognitive brain health.
