Examining Microstructural White Matter in Active Duty Soldiers with a History of Mild Traumatic Brain Injury and Traumatic Stress.

Michael N Dretsch,Jeffery S Katz,Grant L Iverson,Jennifer L Robinson,Thomas S Denney,Gopikrishna Deshpande,Rael T Lange,Adam Goodman,Thomas A Daniel

doi:10.2174/1874440001711010046

Abstract

Background:There is a high comorbidity of posttraumatic stress (PTS) and mild traumatic brain injury (mTBI), with largely overlapping symptomatology, in military service members.Objective:To examine white matter integrity associated with PTS and mTBI as assessed using diffusion tensor imaging (DTI).Method:Seventy-four active-duty U.S. soldiers with PTS (n = 16) and PTS with co-morbid history of mTBI (PTS/mTBI; n = 28) were compared to a military control group (n = 30). Participants received a battery of neurocognitive and clinical symptom measures. The number of abnormal DTI values was determined (>2 SDs from the mean of the control group) for fractional anisotropy (FA) and mean diffusivity (MD), and then compared between groups. In addition, mean DTI values from white matter tracts falling into three categories were compared between groups: (i) projection tracts: superior, middle, and inferior cerebellar peduncles, pontine crossing tract, and corticospinal tract; (ii) association tracts: superior longitudinal fasciculus; and (iii) commissure tracts: cingulum bundle (cingulum-cingulate gyrus and cingulum-hippocampus), and corpus callosum.Results:The comorbid PTS/mTBI group had significantly greater traumatic stress, depression, anxiety, and post-concussive symptoms, and they performed worse on neurocognitive testing than those with PTS alone and controls. The groups differed greatly on several clinical variables, but contrary to what we hypothesized, they did not differ greatly on primary and exploratory analytic approaches of hetero-spatial whole brain DTI analyses.Conclusion:The findings suggest that psychological health conditions rather than pathoanatomical changes may be contributing to symptom presentation in this population.

Highlights

A large number of military service members have sustained a traumatic brain injury (TBI) while on active duty, the majority of which are categorized in the mild range [1]
The findings suggest that psychological health conditions rather than pathoanatomical changes may be contributing to symptom presentation in this population
The posttraumatic stress (PTS)/mild traumatic brain injury (mTBI) group was less educated and had higher levels of prior traumatic events compared to controls, but no difference in their childhood environment or age

Summary

Introduction

A large number of military service members have sustained a traumatic brain injury (TBI) while on active duty, the majority of which are categorized in the mild range (mTBI) [1]. There is a high prevalence of posttraumatic stress (PTS) in service members who deployed for Operation Iraqi Freedom, Operation Enduring Freedom, and Operation New Dawn [3 - 7]. In service members that go on to develop persistent postconcussive symptoms, due to the high overlap of symptoms associated with PTS, teasing apart the etiology of the symptoms can be difficult [6, 8, 9]. There is a high comorbidity of posttraumatic stress (PTS) and mild traumatic brain injury (mTBI), with largely overlapping symptomatology, in military service members

Results

Discussion

Conclusion