Physiological emotional under-arousal in individuals with mild head injury

Abstract

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.

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

“…It was hypothesized that athletes would endorse more aggression compared to nonathletes and that individuals with a history of concussion would endorse higher levels of aggression compared to those without a prior concussion, independent of athletic status. Consistent with the continuum of injury severity (Iverson & Lange, 2009) and previous research (e.g., Baker & Good, 2014; van Noordt & Good, 2011), those with a history of concussion were expected to exhibit lower levels of baseline physiological arousal (i.e., attenuated EDA) compared to those without a prior concussion. Lastly, as per the somatic marker hypothesis (Damasio, 1994), it was predicted that physiological arousal would mediate the relationship between injury severity and aggression whereby those with more severe concussive impacts would exhibit lower levels of arousal and subsequently higher levels of reactive aggression.…”

“…Importantly, when investigating potential mechanisms of this relationship, it was found that physiological arousal was a partial mediator of the relationship between injury severity and physical aggression, such that those with more severe injuries exhibited lower levels of physiological arousal, which in turn accounted for higher levels of aggression. Consistent with previous work indicating physiological dysregulation after concussion (e.g., Alcock et al., 2018; Baker & Good, 2014; van Noordt & Good, 2011), these findings imply that aggressive behaviors may be associated with concussion history (i.e., physiological underarousal), over and above athletic status, due to physiological unpreparedness. Alternatively, due to their chronically underaroused state, these athletes may be more likely to engage in aggressive forms of play in an attempt to increase their baseline levels of alertness; however, the current study did not directly test these potential explanations.…”

“…First, concussion history was determined via retrospective self‐report; thus, many of the reported injuries remain unconfirmed by collateral sources. However, it has been found that the majority of university students reporting concussions indicate that they were not admitted to a treating medical facility for their injuries (e.g., Baker & Good, 2014; Segalowitz & Lawson, 1995), thereby limiting collateral evidence, and the possible impact of retrospective reporting bias is somewhat mitigated in this study in that participants were not motivated by litigation or incentives, nor were they aware of the researchers’ added interest in head injury upon recruitment. Further, while the majority of injuries captured in this study were mild in nature according to injury severity indices, it is acknowledged that the ACRM criteria allow for moderate and severe TBI classifications to fall into this group; thus, this research may include a broader spectrum of individuals across the continuum and may not be restricted to the mild category.…”

“…The vmPFC's location proximal to the orbital bones of the skull (Morales, Diaz‐Daza, Hlatky, & Hayman, 2007) renders it more susceptible to disruption following rapid acceleration/deceleration of the head; as a result, attenuated arousal is experienced across the spectrum of injury severity (Iverson & Lange, 2009)—even after milder injuries (Alcock, Gallant, & Good, 2018; Baker & Good, 2014; van Noordt & Good, 2011). Physiological underarousal, indexed by dampened respiration, electrodermal activation (EDA), and heart rate (Craig, 1968; Lazarus, Speisman, & Mordkoff, 1963), has been proposed as a mechanism of impulsivity and risk‐taking behavior.…”

Mild Traumatic Brain Injury Chronically Impairs Sleep- and Wake-Dependent Emotional Processing

“…11 In the past, self-reported mild TBI has been linked with cognitive, neuropsychological, and physical impairments. [26][27][28][29][30] Therefore, we feel participants' self-reports are a valid measure of having had a concussion. Participants in the non-TBI group were required to have never had a concussion.…”