Lateralization of Neurobiological Response in Adolescents with Post-Traumatic Stress Disorder Related to Severe Childhood Sexual Abuse: the Tri-Modal Reaction (T-MR) Model of Protection

Abstract

This study inquires into neurobiological response to stress and its clinical correlates among adolescents with post-traumatic stress disorder (PTSD). Structural magnetic resonance imaging (MRI) measures of cerebral anatomy were carried out on 23 female adolescents with PTSD related to severe childhood sexual abuse and 21 matched healthy controls. Clinician Administered PTSD Scale for Children and Adolescents, Adolescent Dissociative Experiences Scale, Childhood Trauma Questionnaire, Schedule for Affective Disorders and Schizophrenia for School Age Children, Beck Depression Scale, and a set of neuro-cognitive tests were administered to all participants. Compared to controls, PTSD group bilaterally had smaller amygdala, hippocampus, anterior cingulate, and thinner prefrontal cortex but normal thalamus. Further analyses within the PTSD group suggested an association between symptoms of PTSD and sizes of right brain structures including smaller amygdala but larger hippocampus and anterior cingulate. Thinner right prefrontal cortex and larger right thalamus seemed to be related to denial and response prevention, respectively. Being related to both hemispheres, dissociative amnesia was negatively associated with proportion of the right amygdala to right thalamus and to both left and right prefrontal cortex. Suggesting a neuro-protective effect against traumatic stress at least through adolescence, depersonalization-derealization and identity alteration were correlated with thicker left prefrontal cortex. Unlike the lateralization within PTSD group, correlations between regions of interest were rather symmetrical in controls. The graded response to stress seemed to be aimed at mental protection by lateralization of brain functions and possibly diminished connection between two hemispheres. A Tri-Modal Reaction (T-MR) Model of protection is proposed.

Hippocampal subfields alterations in adolescents with post‐traumatic stress disorder

“…However, these studies could have failed to detect any alteration because of the use of low resolution structural MRI images or segmentation techniques that may not have been adapted to pediatric populations. Indeed, using high‐resolution MRI images and manual segmentation, we found smaller hippocampal volumes in adolescents with PTSD, in accordance with Mutluer et al () who also manually segmented the whole hippocampus in adolescents with PTSD.…”

Parallel-Distinct Structures of Internal World and External Reality: Disavowing and Re-Claiming the Self-Identity in the Aftermath of Trauma-Generated Dissociation

“…A recent MRI study (Mutluer et al, in press) conducted on adolescent girls with PTSD due to severe sexual abuse yielded bilateral decrease in volumes of amygdala, anterior cingulate, hippocampus, and diminished thickness of prefrontal cortex compared to the healthy controls. However, analyses within the PTSD group revealed a tendency of lateralization in findings showing significant negative correlations between clinical symptoms of Simple and Complex PTSD and volume changes of the right hemisphere subcortical structures.…”

“…Constituting resistances of the “trauma-self” (Öztürk and Şar, 2016a), such relatively subtle and chronic phenomena are associated with NWS (i.e., that the individual appears “normal” but not crisis-prone in daily life) rather than TRASC which is related to more explicite dissociation. This condition reflects the secondary phase (“Trauma-Illness” as opposed to “Inflammation” and “Estrangement” phases) of post-traumatic process in the proposed “Tri-Modal (T-MR) Reaction Model of Protection” (Mutluer et al, in press) as inspired by findings of a recent neurobiological study on adolescent girls with PTSD due to severe sexual abuse.…”

“…In support of the observations previously made by Farina et al (2014), this symmetrical appearance of correlations suggested better connectivity of the brain in the healthy group. Unlike dissociation, denial or minimization of childhood trauma seemed to be “toxic” in that it was negatively correlated with the thickness of the right prefrontal cortex (Mutluer et al, in press). …”

“…Underlining the significance of “betrayal” (Freyd, 1994), in a neurobiological study on adolescent girls with PTSD due to severe sexual abuse (Mutluer et al, in press), those abused by their biological father or brother (i.e., perpetrator in “closer” relationship with the victim) reported more dissociative amnesia and absorption compared to victims of other perpetrators. They also had smaller left anterior cingulate while right anterior cingulate was larger in coitus group (i.e., more severe abusive act) compared to those with other types of SA.…”