Blast concussion and posttraumatic stress as predictors of postcombat neuropsychological functioning in OEF/OIF/OND veterans.

Abstract

Objectives: Many combat Veterans exhibit cognitive limitations of uncertain origin. In this study, we examined factors that predict cognitive functioning by considering effects of blastrelated concussion (BRC), non-blast-related concussion (NBRC), and posttraumatic stress disorder (PTSD) symptoms. Analyses specifically tested whether: (a) BRC and NBRC were distinct in their prediction of cognitive performance; (b) a dose-response relationship existed between recurrent concussion (BRC and NBRC) and cognitive impairment; and (c) PTSD symptoms mediated the relationship between BRC and cognitive performance.Method: Two-hundred eighty Veterans with combat zone deployment histories completed semistructured clinical interviews to define BRC and NBRC histories, current and past mental health disorders, and dimensional ratings of PTSD symptomatology. Participants were also administered a number of neuropsychological measures to appraise cognitive functioning.Results: A structural equation model (SEM) suggested that BRC and NBRC were not distinct in their prediction of cognitive performance, and there was no evidence that recurrent concussion (blast or non-blast) was directly associated with cognitive performance. BRC was significantly associated with PTSD symptoms (r = .24), PTSD symptoms were significantly associated with cognitive performance in the SEM (r = −.27), and PTSD symptoms significantly mediated the link between BRC and cognitive performance (p = .03).Conclusions: These results suggest that concussion history fails to directly contribute to cognitive performance, regardless of mechanism (blast or non-blast) and recurrence. BRC is nonetheless unique in its contribution to PTSD and PTSD-related cognitive deficits. Results support interventions specific to PTSD management in the interest of promoting neuropsychological functioning among war Veterans.

Blast in Context: The Neuropsychological and Neurocognitive Effects of Long-Term Occupational Exposure to Repeated Low-Level Explosives on Canadian Armed Forces' Breaching Instructors and Range Staff

“…In the case of PCL-5 measures, individuals with multiple deployments showed consistently higher scores (median value of 7), which corresponds with greater PTSD symptomatology ( 58 ). Although well-below the threshold for clinical diagnosis (i.e., PCL-5 score ≥ 33), this observation is consistent with a large body of research suggesting a link between multiple deployments, mTBI and increasing vulnerability to developing PTSD and other mental health problems ( 59 , 60 ). These findings should prove useful as researchers work toward developing improved diagnostic tools for distinguishing between the effects of these three conditions that frequently overlap in this population exposed routinely to low-level blast ( 61 , 62 ).…”

Study design for a randomized clinical trial of cognitive-behavioral therapy for posttraumatic headache

“…Military veterans are more likely than civilians to experience head injury associated with blast exposure (i.e., barotrauma) or overpressure associated with discharge of firearms. Some suggest that barotrauma may have unique effects on the brain that could result in characteristically different rates and presentations of headache [ 73 ], though the body of research is equivocal, with some reporting evidence that head injury mechanisms have little differential impact on brain functioning [ 74 ]. Unfortunately, the body of literature describing unique contributions of barotrauma to TBI (and TBI-related headache) is sparse and does not provide enough information to lead to a reasonable stratification of head injury type (i.e., barotrauma versus blunt trauma).…”

Medico‐Legal Aspects of Concussion

“…Population based estimates of PTSD in the general community range from 7 to 8% and higher rates (up to approximately 20%) have been reported in American service members returning from deployment 82‐84 Research utilizing a screening measure to examine symptoms of PTSD in patients admitted to the hospital and diagnosed with mTBI described PTSD as a rare comorbidity following their injury (2.8%) 85 . Nelson et al observed a link between PTSD symptoms and concussion in a sample of veterans; yet findings lack generalizability to the general population 86 …”