Elevated Delta and Theta Waves During Letter Number Reordering Tasks in Concussed Individuals

Abstract: As the prevalence of sports related concussions rises, the long-term effects of concussions have garnered increasing research attention. Previous research has demonstrated that certain dimensions of executive function are especially susceptible to mild traumatic brain injury, or mTBI, specifically working memory and attention. Previous studies using electroencephalogram (EEG) have found that increased delta and theta frequencies are associated with difficulties in cognition, hyperactivity and learning deficits in concussed individuals after mTBI. This study utilized continuous EEG during a letter number sequencing task on concussed and non-concussed individuals to assess possible deficits related to working memory. It was hypothesized that concussed student athletes would display abnormal EEG wave patterns during the Millisecond Letter Number Sequencing Task as a result of the long-term consequences associated with mTBI. Results of this study showed evidence of a significant increase in both the delta and theta waves in concussed individuals during completion of the letter number reordering span task. This study allowed for the conclusion that concussed individuals showed altered activity within the frontal lobe region during working memory tasks in the form of elevated delta and theta waves resulting from hyperactivity of various brain circuits involved in the complex working memory network. Different brain regions may have been working harder to recruit the resources necessary for completion of the LNS tasks, as a result of the consequences of the brain injury. Further research is required to describe the major cognitive resources lost due to concussion and to specify the circuits exhibiting hyperactivity.

Key Words: Concussion; Delta-Waves; Theta- Waves; Letter-Number-Task; Working Memory; Attention; Executive-Function

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