Research Reports - Physiological emotional under-arousal in individuals with mild head injury
Brain Inj. 2014;28(1):51-65
Baker JM, Good DE
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
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.