Inter-hemispheric functional and anatomical connectivity abnormalities in traffic accident-induced PTSD: a study combining fMRI and DTI

- VMHC is a new measurement in inter-hemispheric functional connectomics.
- VMHC and DTI tractography analysis supports brain connectivity deficits of PTSD.
- There is evidence of inter-hemispheric connectivity involvement before diagnosis.
- It may contribute towards the development of effective methods of prevention.

BackgroundAberrant brain functional and structural changes are considered to be one of the important mechanisms underlying post-traumatic stress disorder (PTSD). However, it remains unclear whether inter-hemispheric connection is changed. The current study aimed to identify the inter-hemispheric functional and anatomical connectivity changes in patients who consequently develop PTSD using the voxel-mirrored homotopic connectivity (VMHC) analysis and diffusion tractography techniques.MethodsResting-state fMRI and DTI data were acquired on victims who had experienced traffic accidents within 2 days after the traumatic event. The diagnosis was made using the Clinician-Administered PTSD Scale at 1 or 6 months later. Fifteen trauma-exposed victims met the criteria for diagnosis of PTSD and 14 trauma-exposed victims who did not develop PTSD at 6 months after trauma were selected as the control group.ResultsCompared with the victims without PTSD, the victims with PTSD exhibited an abnormal homotopic pattern with decreased VMHC in the superior/middle frontal gyrus before diagnosis. The regions showing abnormal functional connectivity were then chosen as regions of interest for an analysis of DTI tractography. Decreased fractional anisotropy values in the genu of the corpus callosum were found in the victims with PTSD. Greater WM disruptions within 2 days predicted greater symptom severity at diagnosis.LimitationsThe study was lack of comparison with controls who did not experience a traumatic event.ConclusionOur results suggest that the inter-hemispheric functional and structural connectivity is impaired in PTSD within 2 days, which may be the potential marker showing predisposition towards developing PTSD.