Dawn Good

Mild head injury and sympathetic arousal: Investigating relationships with decision-making and neuropsychological performance in university students

Summary: The purpose of this study was to examine the relationships between neuropsychological performance, physiological arousal and decision-making in university students who have or have not reported a history of mild head injury (MHI). Methods: Forty-four students, 18 (41%) reporting a history of MHI, performed a design fluency task and the Iowa Gambling Task (IGT) while electrodermal activity (EDA) was recorded. Results: General cognitive ability and overall choice outcomes did not differ between groups. However, self-reported MHI severity predicted decision-making performance such that the greater the neural indices of trauma, the more disadvantageous the choices made by participants. As expected, both groups exhibited similar base levels of autonomic arousal and physiological responses to reward and punishment outcomes; however, those reporting MHI produced significantly lower levels of EDA during the anticipatory stages of decision-making. Conclusions: Overall, these findings encourage the acceptance of head injury as being on a continuum of brain injury severity, as MHI can emulate neurophysiological and neuropsychological features of more traumatic cases and may be impacting mechanisms which sustain adaptive social decision-making.

Physiological emotional under-arousal in individuals with mild head injury

Abstract Primary objectives: This study examined the potential emotional sequelae following self-reported mild head injury (MHI; e.g. ‘altered state of consciousness’ [ASC]) in university students with a particular focus on arousal status and responsivity to experimental manipulation of arousal. Research design: A quasi-experimental design (n = 91) was used to examine arousal status (self-reported and physiological indices) and response to manipulated arousal (i.e. induced psychosocial stress/activation; reduced activation/relaxation) between persons who acknowledged prior MHI and persons with no-MHI. Main outcome and results: University students who self-reported MHI were physiologically under-aroused and less responsive to stressors (both laboratory and environmental) compared to their no-MHI cohort. Those with reported loss of consciousness demonstrated the most attenuated emotional arousal responses (i.e. flattened electrodermal responsivity) relative to those with only a reported ASC, followed by those with no-MHI. Conclusions: The under-arousal in traumatic brain injury has been hypothesized to be associated with ventromedial prefrontal cortex disruption. This under-arousal may be mirrored in persons who self-report experiencing subtle head trauma. Students who reported MHI may be less able to physiologically respond and/or cognitively appraise stressful experiences as compared to their no-MHI cohort; and experience subtle persistent consequences despite the subtle nature of the reported head trauma.

Moral decision-making in university students with self-reported mild head injury.

ABSTRACT Converging evidence shows that the prefrontal cortex is involved in moral decision-making. Individuals who have suffered injury to the ventromedial prefrontal cortex are more willing to endorse personal moral transgressions (e.g., make their decisions faster, and have attenuated sympathetic responses to those violations). We examined whether university students who have experienced a mild head injury (MHI), and are asymptomatic, present with a similar pattern of responding to moral dilemmas. Students reporting a history of MHI responded more quickly when making moral choices and exhibited less reticence toward the endorsement of personal moral transgressions than their non-MHI counterparts. Our results are consistent with studies involving persons with more serious, and evident, neuronal injury, and emphasize the important relationship between head injury and moral decision-making.

The relationship between concussion and alcohol consumption among university athletes

Introduction This study investigated concussion as a potential risk factor for increased alcohol consumption in university athletes. Methods Using a cross-sectional design, 41 university students (37% with a history of concussion) completed self-report measures, while electrodermal activation (EDA) was recorded for each participant to capture baseline physiological arousal. Results As expected, concussion status significantly predicted alcohol consumption over and above athletic status, b = 0.34, p = 0.034, 95% CI [0.195, 4.832], such that those with a prior concussion history engaged in greater alcohol consumption. Importantly, concussion status also significantly predicted baseline physiological arousal, b = −0.39, p = 0.014, 95% CI [−0.979, −0.120], such that those with a history of concussion exhibited lower EDA. Conclusions Elevated alcohol consumption among athletes is a pronounced associate of concussion in sports and may be a behavioral reflection of disruption to the orbitofrontal cortex – an area implicated in inhibition.

Physiological underarousal as a mechanism of aggressive behavior in university athletes with a history of concussion

Research has indicated that athletes who engage in high‐risk athletic activities, such as football and hockey, have riskier personalities than their low‐risk and nonathlete counterparts (Ahmadi et al., 2011, Procedia Soc Behav Sci, 30 and 247–251; Zuckerman, 1983, Biological bases of sensation seeking, impulsivity, and anxiety, Lawrence Erlbaum Assoc Inc.). For instance, increased sensation‐seeking and aggression are common in high‐risk athletes, rendering these individuals more likely to sustain a subsequent injury, such as concussion. Elevated levels of certain personality traits, including impulsivity and aggression, have also been observed after concussion (Goswami et al., 2016, Brain Struct Funct, 221 and 1911–1925). The purpose of this study therefore was to determine whether aggressive behavior in university athletes may be accounted for, in part, by a history of concussion, rather than exclusively athletic status.