The relation between posttraumatic stress disorder and mild traumatic brain injury acquired during Operations Enduring Freedom and Iraqi Freedom.

OBJECTIVE: To understand the relations of mild traumatic brain injury (TBI), blast exposure, and brain white matter structure to severity of posttraumatic stress disorder (PTSD). DESIGN: Nested cohort study using multivariate analyses. PARTICIPANTS: Fifty-two OEF/OIF veterans who served in combat areas between 2001 and 2008 were studied approximately 4 years after the last tour of duty. MAIN MEASURES: PTSD Checklist-Military; Combat Experiences Survey, interview questions concerning blast exposure and TBI symptoms; anatomical magnetic resonance imaging (MRI), and diffusion tensor imaging (DTI) scanning of the brain. RESULTS: PTSD severity was associated with higher 1st percentile values of mean diffusivity on DTI (regression coefficient [r] = 4.2, P = .039), abnormal MRI (r = 13.3, P = .046), and the severity of exposure to combat events (r = 5.4, P = .007). Mild TBI was not significantly associated with PTSD severity. Blast exposure was associated with lower 1st percentile values of fractional anisotropy on DTI (odds ratio [OR] = 0.38 per SD; 95% confidence interval [CI], 0.15-0.92), normal MRI (OR = 0.00, 95% likelihood ratio test CI, 0.00-0.09), and the severity of exposure to traumatic events (OR = 3.64 per SD; 95% CI, 1.40-9.43). CONCLUSIONS: PTSD severity is related to both the severity of combat stress and underlying structural brain changes on MRI and DTI but not to a clinical diagnosis of mild TBI. The observed relation between blast exposure and abnormal DTI suggests that subclinical TBI may play a role in the genesis of PTSD in a combat environment.

Reliability, sensitivity, and specificity of the VA traumatic brain injury screening tool.

OBJECTIVE: To provide item analyses, estimates of temporal reliability and internal consistency, and examination of the sensitivity and specificity of a traumatic brain injury-screening tool. PARTICIPANTS: Five hundred veterans of the wars in Iraq and Afghanistan enrolled in the study, approximately half of whom (248) volunteered. The remaining 252 participants were referred to Veteran Affairs (VA) neuropsychology or polytrauma clinics. DESIGN: This psychometric study constitutes part of a larger 4-year, multisite prospective cohort study of veterans returning from Iraq and Afghanistan. SETTING: Five VA medical centers and one VA outpatient clinic. MAIN MEASURES: Veteran traumatic brain injury screening tool (VATBIST), a structured diagnostic interview for traumatic brain injury; a military-oriented posttraumatic stress disorder checklist. RESULTS: The VATBIST appeared to have high-internal consistency (0.77) and test-retest reliability (0.80), high sensitivity (0.94) and moderate specificity (0.59). Diagnostic odds ratios for the screening tool ranged from 12.6 for the total sample to 24, when veterans with probable posttraumatic stress disorder were excluded from analysis. CONCLUSIONS: The VATBIST appears to be a reliable and valid instrument. The presence of significant posttraumatic stress disorder symptoms, however, reduces the accuracy of the measure and highlights the need for careful clinical follow-up of persons who screen positive.

Longitudinal study of objective and subjective cognitive performance and psychological distress in OEF/OIF Veterans with and without traumatic brain injury.

OBJECTIVE: To describe changes in post-deployment objective and subjective cognitive performance in combat Veterans over 18 months, relative to traumatic brain injury (TBI) status and psychological distress. METHOD: This prospective cohort study examined 500 Veterans from Upstate New York at four time points, six months apart. TBI status was determined by a structured clinical interview. Neuropsychological instruments focused on attention, memory, and executive functions. Subjective cognitive complaints were assessed with the Neurobehavioral Symptom Inventory (NSI). A psychological distress composite included measures of post-traumatic stress disorder (PTSD), depression, and generalized anxiety. RESULTS: Forty-four percent of the sample was found to have sustained military-related TBI, 97% of which were classified as mild (mTBI), with a mean time since injury of 41 months. Veterans with TBI endorsed moderate cognitive symptoms on the NSI. In contrast to these subjective complaints, mean cognitive test performance was within normal limits at each time point in all domains, regardless of TBI status. Multilevel models examined effects of TBI status, time, and psychological distress. Psychological distress was a strong predictor of all cognitive domains, especially the subjective domain. Substantial proportions of both TBI+ and TBI- groups remained in the clinically significant range at the initial and final assessment for all three distress measures, but the TBI+ group had higher proportions of clinically significant cases. CONCLUSIONS: Objective cognitive performance was generally within normal limits for Veterans with mTBI across all assessments. Psychological distress was elevated and significantly related to both objective and subjective cognitive performance.

Dimensionality, reliability, and validity of the combat experiences scale.

Few studies have measured combat exposure during deployment to a war zone. Valid, reliable, and specific measurement is needed to broaden existing knowledge of combat experiences to accurately answer clinically important questions regarding postcombat treatment and recovery, particularly with the recognition of new kinds of combat and resulting psychological sequelae. The Combat Experiences Scale (CES) is a 33-item measure that assesses deployment-related experiences. The psychometrics of this measure, however, were undefined before this study. The purpose of this study was to examine aspects of internal and external validity of the CES. Data were collected as part of a study of 500 veterans of the conflicts in Iraq and Afghanistan across five Veterans Affairs medical centers in Upstate New York. An exploratory factor analysis suggested that three factors represented the scale well: Exposure to Combat Environment, Physical Engagement, and Proximity to Serious Injury and Death. The CES scores showed adequate internal consistency, and evidence for convergent validity and discriminant validity was also found. This study underscores the importance of casting a wide net with regard to the assessment of deployment-related experiences and provides evidence that probable post-traumatic stress disorder, depression, and anxiety are highly correlated with all forms of deployment-related experiences.