Loss of emotional experience after traumatic brain injury: Findings with the startle probe procedure.

Abstract

The authors used affective modulation of the eyeblink startle response to examine the impact of traumatic brain injury (TBI) on emotional reactions to pictures. Participants were 13 individuals with severe TBI and 24 controls. Participants were presented with pictures that differed in affective valence (e.g., mutilated bodies, erotic couples, and household objects) while the eyeblink startle response to an acoustic probe was measured. Startle amplitude was used to assess valence of emotional response, and startle latency was used to index interest in the pictures. Subjective ratings of the affect and arousal elicited by the various pictures were also obtained. TBI impaired startle potentiation to unpleasant pictures but not startle attenuation to pleasant pictures. Further, subjective ratings indicated that TBI participants found unpleasant pictures less arousing than did controls. The results are consistent with recent evidence of differential impairment in negative versus positive emotions after TBI and are discussed in relation to 2 competing explanations of startle modulation.

Neurophysiological correlates of dysregulated emotional arousal in severe traumatic brain injury

“…Specifically, the physiological evidence from TBI studies points to muted skin conductance, reduced eyeblink startle and facial EMG (electromyography) responses (Blair and Cipolotti, 2000;de Sousa et al, 2012de Sousa et al, , 2011de Sousa et al, , 2010Hopkins et al, 2002;McDonald et al, 2011;Sanchez-Navarro et al, 2005;Saunders et al, 2006) to aversive stimuli in particular, including angry facial expressions, distressing film clips, and unpleasant pictures (e.g., IAPS; Sanchez-Navarro et al, 2005). Deficits in psychophysiological responding to aversive stimuli in severe TBI are reflected in lower self-reported levels of arousal (e.g., Saunders et al, 2006) and valence (de Sousa et al, 2010). TBI adults who self-report low empathy levels also exhibit reduced facial muscle responding to both pleasant and unpleasant stimuli, as well as lower autonomic arousal (i.e., skin conductance, de Sousa et al, 2012).…”

Emotion perception deficits following traumatic brain injury: A review of the evidence and rationale for intervention

“…Finally, recent research has raised the possibility that emotional reactivity may be disturbed following TBI (Blair & Cipolotti, 2000;Croker & McDonald, 2005;Hornak et al, 1996;Saunders et al, 2006), including reactivity to facial expressions of others (Angrilli et al, 1999;Blair & Cipolotti, 2000;Hopkins et al, 2002). There is only very limited evidence, to date, that affective reactivity and the ability to accurately recognize emotions in others are related following TBI (Croker & McDonald, 2005;Hornak et al, 1996).…”

Long-Lasting Suppression of Acoustic Startle Response after Mild Traumatic Brain Injury

“…ASR is a highly conserved, defensive response to a loud auditory stimulus that can involve whole-body movement or more subtle movement (i.e., eyeblink), 4 utilizes a simple trisynaptic reflex in the brainstem and spinal cord, 5 and indicates integrity of sensorimotor processes, nonassociative learning, and psychological state of a subject (i.e., exaggerated in anxious states and fear). 6,7 In humans, moderate-to-severe TBI suppressed ASR in one study, 8 but not in another. 9 The variable results may be owing to differences in injury parameters, such as severity, dynamics, location, and time after injury that are difficult to control in human studies.…”