Impairments in Physiological Reactivity to Emotive Stimuli After Traumatic Brain Injury: A Systematic Review of Skin Conductance and Heart Rate Variability Evidence

Objective: To examine evidence of impairments in physiological reactivity to emotive stimuli following traumatic brain injury (TBI). Methods: A search of PsychINFO, CINAHL (Cumulative Index to Allied Health Literature), Web of Science, EMBASE (Excerpta Medica dataBASE), and Scopus databases was conducted from 1991 to June 24, 2021, for studies comparing changes in skin conductance or heart rate variability to emotive stimuli between adults with TBI and controls. Two reviewers independently assessed eligibility and rated methodological quality. Results: Twelve eligible studies examined physiological reactivity to laboratory-based emotive stimuli, which included nonpersonal pictures/videos, posed emotion, stressful events, and personal event recall. Overall, 9 reported evidence that individuals with TBI experience lower physiological reactivity to emotive stimuli compared with healthy controls, although the findings varied according to the type and valence of emotional stimuli and physiological parameter. Most studies using nonpersonal pictures or videos found evidence of lower physiological reactivity in TBI participants compared with controls. Conclusions: Based on laboratory-based studies, individuals with TBI may experience lower physiological reactivity to emotive stimuli. Further research is needed to investigate physiological responses to personally relevant emotional stimuli in real-world settings and to understand the interplay between physiological reactivity, subjective experiences, and behavior.