Sensory overload and imbalance: Resting-state vestibular connectivity in PTSD and its dissociative subtype.

Summary

People with posttraumatic stress disorder (PTSD) and its dissociative subtype show altered brain connectivity between the vestibular system—which integrates sensory information about body orientation—and cortical regions involved in self-awareness. Using resting-state fMRI, researchers compared 60 people with PTSD, 41 with the dissociative subtype, and 40 healthy controls. The PTSD and control groups had stronger connectivity between the vestibular nuclei and the parieto-insular vestibular cortex and dorsolateral prefrontal cortex than the dissociative subtype group. Greater depersonalization and derealization symptoms correlated with weaker connectivity in the right supramarginal gyrus. These findings suggest that disrupted vestibular multisensory integration may contribute to distinct symptom profiles in PTSD and its dissociative subtype.

Study at a glance

Abstract

The vestibular system integrates multisensory information to monitor one's bodily orientation in space, and is influenced by interoceptive awareness. Post-traumatic stress disorder (PTSD) involves typically alterations in interoceptive and bodily self-awareness evidenced by symptoms of hyperarousal, as well as of emotional detachment, including emotional numbing, depersonalization, and derealization. These alterations may disrupt vestibular multisensory integration between the brainstem (vestibular nuclei) and key vestibular cortical regions (parieto-insular vestibular cortex, prefrontal cortex). Accordingly, this study examined functional connectivity of the vestibular system in PTSD and its dissociative subtype. Using resting-state fMRI data in SPM12 and PickAtlas, a seed-based analysis was employed to examine vestibular nuclei functional connectivity differences among PTSD (n = 60), PTSD dissociative subtype (PTSD + DS, n = 41) and healthy controls (n = 40). Increased vestibular nuclei functional connectivity with the parieto-insular vestibular cortex and the dorsolateral prefrontal cortex (dlPFC) was observed in PTSD and in controls as compared to PTSD + DS, and greater connectivity with the posterior insula was observed in controls as compared to PTSD. Interestingly, whereas PTSD symptom severity correlated negatively with dlPFC connectivity, clinical measures of depersonalization/derealization correlated negatively with right supramarginal gyrus connectivity. Taken together, decreased vestibular nuclei functional connectivity with key cortical vestibular regions in the PTSD + DS as compared to PTSD group, and its negative correlations with PTSD and dissociative symptoms, suggest that dysregulation of vestibular multisensory integration may contribute to the unique symptom profiles of each group. Further research examining disruption of vestibular system neural circuitry in PTSD and its dissociative subtype will be critical in capturing the neurophenomenology of PTSD symptoms and in identifying psychotherapeutic techniques that target dysfunction related to the vestibular system.