Event-Related Potentials in Concussion Detection and Recovery

Abstract

Concussion, defined as a functional injury with complex symptomatology, affects millions annually and has been classified as a serious public health concern. Clinical tools currently available for concussion assessment fail to objectively measure cognitive function and thus, are inadequate for proper evaluation of the cognitive dysfunctions associated with the injury. As a result, investigation into the neurological consequences associated with concussion has become a prominent focus in neuroscience research. Traditionally, neuroimaging methods have been used primarily on concussion detection, while behavioural and neuropsychological assessments have been used for both concussion detection and cognitive-performance tracking. However, to date, minimal work has explored the use of neuroimaging to track the consequences of concussion at the neurophysiological level. Accordingly, the present thesis sought to investigate the clinical applicability of electroencephalography (EEG) as an effective neuroimaging tool capable of concussion detection, as well as its ability to objectively track neurophysiological changes over time. Event-related potentials (ERPs) were used to assess specific functions, or more accurately, dysfunctions of select cognitive processes as reflected by electrophysiological changes in the brain. Specifically, the Mismatch Negativity (MMN), N2b, and P300 were investigated to evaluate memory, attention, and executive control in concussed populations. The results of this thesis demonstrated alterations in each of the aforementioned ERPs, signifying cognitive dysfunctions linked to neurophysiological abnormalities in concussed populations. Of particular importance, Chapter 2 revealed the first instance of MMN abnormalities in a concussed population, Chapter 3 was the first to assess concussed adolescents at the acute stage of their injury, and Chapter 4 demonstrates the potential of ERPs to track neurophysiological changes from the acute to post-acute stages of the injury. Ultimately, the findings presented in this dissertation support the clinical viability of using ERPs to not only detect cognitive dysfunctions associated with concussion, but also to objectively track neurophysiological changes on the path to recovery.