Impact of cognitive exertion on autonomic reactivity in individuals with persistent post-concussive symptoms (P7-1.010)

Abstract

<h3>Objective:</h3> Examine the impact of cognitive exertion on autonomic reactivity in symptomatic and asymptomatic individuals with history of concussion and controls without history of concussion. <h3>Background:</h3> Following concussive head injuries, many individuals continue to experience physical, cognitive, and emotional symptoms that can persist for months or years. Recent studies suggest that concussive head injuries can also produce persistent dysfunction of the autonomic nervous system. However, it remains unclear if acute bouts of cognitive exertion moderate autonomic dysfunction in individuals with persistent post-concussion symptoms. <h3>Design/Methods:</h3> A cross-sectional design was used to investigate autonomic reactivity in 23 individuals without history of concussion (HC-) and 35 individuals with history of concussion, including 20 symptomatic (HCx-S) and 15 asymptomatic (HCx-A). Participants were classified based on clinical history and symptom reports obtained from a comprehensive questionnaire of their medical history and the Rivermead Post-Concussion Questionnaire (RPQ). Participants initially completed a seated, six-minute resting assessment with eyes open in the dimly lit room. They then completed a continuous reaching variant of the traditional Go/NoGo task. Continuous electrocardiography was recorded and utilized to compute time-domain metrics of heart rate variability (HRV) during the resting assessment and cognitive task. <h3>Results:</h3> HCx-S participants reported greater symptom burden on the RPQ and performed significantly worse on the Go/NoGo task compared to HC- and HCx-A participants. While HRV metrics failed to reveal any significant differences between HCx-S, HCx-A, and HC-participants during resting assessment (p’s &gt; 0.8), HCx-S participants exhibited significantly greater HRV than HCx-A and HC-participants during the Go/NoGo task (p’s &lt; 0.03). <h3>Conclusions:</h3> Increased HRV in HCx-S participants compared to HC- and HCx-A participants during the Go/NoGo task indicates that concussion may induce greater autonomic reactivity, characterized by higher levels of vagal/parasympathetic tone. This may reflect impairments in the capacity of the autonomic nervous system to efficiently adapt to situational demands. <b>Disclosure:</b> Dr. Moore has nothing to disclose. Taylor Marie Wynne has nothing to disclose. Dr. Broglio has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for MCW. Dr. Broglio has received personal compensation in the range of $0-$499 for serving as a Consultant for U Calgary. Dr. Broglio has received personal compensation in the range of $5,000-$9,999 for serving as an Expert Witness for Montgomery McCracken Walker &amp; Rhoads LLP. The institution of Dr. Broglio has received research support from DoD. The institution of Dr. Broglio has received research support from NCAA. The institution of Dr. Herter has received research support from Woodcock Institute. The institution of Dr. Herter has received research support from National Institutes of Health. The institution of Dr. Herter has received research support from National Institutes of Health. The institution of an immediate family member of Dr. Herter has received research support from Centers for Disease Control and Prevention.