Affective modulation of the startle reflex following traumatic brain injury

Abstract

Diminished emotional recognition, expression, and responsivity are frequent legacies of traumatic brain injury (TBI) that can have an adverse impact on relationships and psychosocial recovery. However, assessment of emotion responsivity is often difficult because many patients lack insight into their altered personality. To overcome this obstacle, we used a physiological measure of emotion responsivity, the startle reflex, to examine how this can vary according to the affective valence of stimuli by comparing a TBI group with a matched control group. The study also examined whether weaknesses of attention and speed of information processing could account for differences in startle modulation across groups. Sixty-four TBI patients and controls completed the startle reflex procedure. Participants were presented with pictures that differed in affective valence, and measures were taken of eyeblink startle responses to an acoustic probe. Subjective ratings of affect and arousal for each picture were obtained, and TBI patients completed measures of attention and information processing. Results revealed that the TBI group did not show the pattern of startle modulation observed in the control group. Whilst pleasant pictures produced the usual attenuation of the startle response, startle responses to unpleasant pictures were significantly lower in the TBI group than in controls. No significant correlations emerged between startle responses and performance on neuropsychological measures in the TBI group. The TBI group also rated unpleasant pictures as significantly less arousing than did controls. The results provide partial support for a growing body of evidence that has proposed impaired emotion responsivity following TBI.

Learning from the minds of others: A review of social cognition treatments and their relevance to traumatic brain injury

“…Indeed, there are a number of people with TBI who report reduced emotional experiences in general, such as in response to specific visual emotional stimuli (de Sousa, McDonald, & Rushby, 2012;de Sousa et al, 2010;Saunders, McDonald, & Richardson, 2006;Williams & Wood, 2012) or when assuming a posture associated with a given emotion (Dethier, Blairy, Rosenberg, & McDonald, 2013). Further, there is evidence that people with TBI show impaired physiological responses to facial expressions and other emotional visual material, evidenced by lowered mimicry (de Sousa et al, 2012;de Sousa et al, 2010;Dethier, Blairy, Rosenberg, & McDonald, 2012;Soussignan, Ehrle, Henry, Schaal, & Bakchine, 2005), a reduced automatic startle reflex (Neumann, Hammond, Norton, & Blumenthal, 2011;Sanchez-Navarro, Martınez-Selva, & Roma´n, 2005;Saunders et al, 2006;Williams & Wood, 2012), and diminished arousal (measured through skin conductance) to aversive materials (Angrilli, Palomba, Cantagallo, Maietti, & Stegagno, 1999;de Sousa et al, 2012;de Sousa et al, 2010de Sousa et al, , 2011Soussignan et al, 2005). This automatic process whereby one's emotions synchronize with those of others through emotional contagion, is likely to contribute to an individual's experience of affective empathy, and may thus be reduced following a TBI.…”

Emotions Are Rising: The Growing Field of Affect Neuropsychology

“…Furthermore, people with traumatic brain injuries (TBIs), many of whom experience ventromedial frontal pathology, have abnormally low arousal (skin conductance level) at baseline (Fisher, Rushby, McDonald, Parks, & Piguet, 2015; McDonald, Rushby, et al, 2011) and habituate unusually rapidly to angry faces (McDonald, Rushby, et al, 2011). Their startle response is also abnormally unresponsive to negative images (Saunders, McDonald, & Richardson, 2006; Williams & Wood, 2012). A similar lack of startle response was reported in people with amygdala lesions (Angrilli et al, 1996; Buchanan, Tranel, & Adolphs, 2004; Funayama, Grillon, Davis, & Phelps, 2001) supporting the notion that the amygdalae, in concert with the ventromedial frontal lobes, mediate autonomic responses to emotional events with or without conscious awareness.…”

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

“…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. Further, changes in affective states of individuals with TBI were the focus of these studies, not whether or not ASR was altered after TBI.…”