As our knowledge of concussions has grown over the years, so too has the focus and techniques used for treatment. Prior treatments for concussion focused on periods of extended rest with low environmental or physical stimulation, while more modern treatments have recognized the importance of environmental and physical cognitive stimulation to promote neuroplasticity in order to alter (and/or improve) brain structure for functional use (Keenan & Mahaffey, 2017).
Neuroplasticity (or neural plasticity as it is often called) refers to the capacity of an individual’s central nervous system (CNS) to undergo structural and/or functional reorganization in response to changing cognitive demands and/or environmental stimuli (Christiansen & Siebner, 2022). Increased neuroplasticity has been a focus of concussion treatment in many rehabilitation centers to help the brain adapt in the presence of dysfunction (Keenan & Mahaffey, 2017).
There are many ways to stimulate neuroplasticity in an individual suffering from a concussion, one of the most common ways is through chronic aerobic exercise. Aerobic exercise has shown to promote neuroplasticity in two ways.
Firstly, it improves the ventilatory response to exercise to help decrease arterial carbon dioxide partial pressure (PaCO2) during exercise (increased PaCO2 levels can elevate cerebral blood flow out of proportion to exercise causing symptoms such as headache and dizziness) to allow for improved cerebral oxygen uptake during exercise to promote neuroplasticity (Leddy, et al., 2018).
Secondly it has shown to increase the central nervous system (CNS) uptake of brain-derived neurotrophic factor (BDNF), insulin-like growth factor (IGF-1) and vascular endothelial growth factor (VEGF) (El-Sayes, et al., 2018). These three neurotrophins/growth factors work together to cause chemical changes in the brain through neurogenesis (process by which neurons are produced), with VEGF preparing the brain’s environment to be suitable for neuron growth and proliferation of neural precursors, IGF-1 maintains normal brain development/maintenance and BDNF which is for upregulating transcription and signaling cascades to maintain/promote the structural components of neuroplasticity (El-Sayes, et al., 2018). Of these three, BDNF is typically the primary focus of studies on prolonged and chronic aerobic exercise’s effects on neuroplasticity as it is the only one that can be affected by exercise in a non-age dependent manner consistently. By increasing BDNF, we are attempting to promote neuroplasticity by repairing/restoring previously altered neural pathways back to their pre-injury form (Leddy, et al., 2018). By having the patient work at sub-threshold levels, we aim to increase the uptake of BDNF to promote neuroplasticity, without causing a severe increase in concussion symptoms to ensure that the patient can increase the uptake of these molecules to brain without triggering the patient’s symptoms to a point where they are unable to continue long term aerobic exercise.
By having the patient do repeated bouts of exercise, it allows more of the neurotrophic and growth factors to cross the blood-brain barrier, leading to structural, functional, and behavioural changes (El-Sayes, et al., 2018).
References:
- Christiansen, L., & Siebner, H. R. (2022). Neuroplasticity. Neuroplasticity – an overview | ScienceDirect Topics. https://www.sciencedirect.com/topics/neuroscience/neuroplasticity
- El-Sayes, J., Harasym, D., Turco, C. V., Locke, M. B., &; Nelson, A. J. (2018, April 21). Exercise-induced neuroplasticity: A mechanistic model … – sage journals.https://journals.sagepub.com/doi/10.1177/1073858418771538
- Keenan, A., &; Mahaffey, B. (2017). Concussion care: Moving beyond the standard. Missouri medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6140182/
- Leddy, J. J., Haider, M. N., Ellis, M., & Willer, B. S. (2018, August). Exercise is medicine for concussion. Current sports medicine reports. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6089233/
