Tonic Immobility in PTSD: Exacerbation of Emotional Cardiac Defense Response
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AuthorNorte, Carlos Eduardo; Vila Castellar, Jaime; Mata Martín, José Luis; Rodríguez Árbol, Javier
Tonic immobilityCardiac defense responsePost-traumatic stress disorderPTSDHumansHeart rate
Norte CE, Volchan E, Vila J, Mata JL, Arbol JR, Mendlowicz M, Berger W, Luz MP, Rocha-Rego V, Figueira I and Souza GGL (2019) Tonic Immobility in PTSD: Exacerbation of Emotional Cardiac Defense Response. Front. Psychol. 10:1213. [doi: 10.3389/fpsyg.2019.01213]
SponsorshipThis work was supported by National Council for Scientific and Technological Development (CNPq) and Carlos Chagas Filho Foundation of Research Support in Rio de Janeiro (FAPERJ). Partial support was provided by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES – Finance Code 001), and Financiadora de Estudos e Projetos (FINEP – Apoio Institucional 03/2016 – Ref 0354/16).
Among defensive behaviors, tonic immobility (TI) is considered the last defensive resort when life is at extreme risk. Post-Traumatic Stress Disorder (PTSD) is the main psychiatric consequence resulting from exposure to traumatic events. Increasing evidence indicate an association between peritraumatic tonic immobilility and severity of PTSD. Cardiac defense response, a reactivity to perceived danger or threat, has been studied by recording heart rate changes that follows the presentation of an unpredictable intense auditory aversive stimulus. The aim of this study was to investigate potential distinctiveness in cardiac defense response among PTSD patients who presented – compared to those that did not – TI reaction in the laboratory setting. Patients (N = 17) completed the TI questionnaire for signs of immobility elicited by passive listening to their autobiographical trauma script. After a while, they were exposed to an intense white noise, while electrocardiogram was recorded. The heart rate during the 80 s after the noise, subtracted from baseline, was analyzed. Higher reports of TI to the trauma script were associated with stronger and sustained heart rate accelerations after the noise. The effects on cardiac defense response add to increasing evidence that some PTSD patients are prone to repeated re-experiences of TI, which may implicate in a potentially distinct pathophysiology and even a new PTSD subtype.