Brain network architecture changes linked to trauma-related dissociation

Network connectivity can estimate trauma-related dissociative symptoms, distinct from post-traumatic stress disorder (PTSD) and childhood trauma, suggests a study. In addition, between-network brain connectivity may provide a fair estimate of symptom severity, resulting in more objective, clinically useful biomarkers of dissociation and improving our understanding of its neural mechanisms.

“Brain-based measures have the potential to augment symptom reports, although it remains unclear whether brain-based measures of dissociation are sufficiently sensitive and robust to enable individual-level estimation of dissociation severity based on brain function,” the investigators said.

To test the robustness and sensitivity of a brain-based measure of dissociation severity, an intrinsic network connectivity analysis was performed on functional magnetic resonance imaging scans obtained from 65 women with histories of childhood abuse and current PTSD.

The investigators used the Multidimensional Inventory of Dissociation to test for continuous measures of trauma-related dissociation. They also derived connectivity estimated with a novel machine learning technique using individually defined homologous functional regions for each participant.

After controlling for childhood trauma and PTSD severity, the models achieved moderate ability to estimate dissociation, with the default mode and frontoparietal control networks contributing the most to such estimation. On the other hand, all models performed at chance levels when a conventional group-based network parcellation was used.

“Dissociative experiences commonly occur in response to trauma, and while their presence strongly affects treatment approaches in post-traumatic spectrum disorders, their aetiology remains poorly understood and their phenomenology incompletely characterized,” the investigators noted.

“Methods to reliably assess the severity of dissociation symptoms, without relying solely on self-report, would have tremendous clinical utility,” they added.