Test-Retest Reliability of the Blast Exposure Threshold Survey in United States Service Members and Veterans

The Blast Exposure Threshold Survey (BETS) is a recently developed measure of lifetime blast exposure. Although promising, it is considered a fundamental tenet to establish that the BETS (and other measures like it) have good psychometric properties before it can be recommended for clinical use. The purpose of this study was to examine the test-retest reliability of the BETS in a military sample. Participants were 83 United States service members and veterans prospectively recruited from three military medical treatment facilities and from the community. Participants were classified into two broad groups as part of a larger study: traumatic brain injury (TBI; n = 41; mild-severe TBI) and controls (n = 42; injured and non-injured controls). Participants completed the BETS, Neurobehavioral Symptom Inventory, and a brief structured interview to gather basic demographic, military, and injury-related information (e.g., age, education, deployments, etc.). In addition, participants completed the BETS on a second occasion (T2) 3 weeks following the first administration (T1). Using Spearman rho correlation analyses, the test-retest reliability of the BETS Generalized Blast Exposure Value (GBEV) was classified as "acceptable" (r = 0.76). However, when comparing individual responses across T1 and T2, 33% of the sample reported significant inconsistencies in the endorsement of the five weapons categories. The most problematic inconsistency (∼10% of the sample) related to the failure of some participants to consistently endorse, or not endorse, exposure to a weapons category at T1 and T2 (e.g., T1 = exposure present; T2 = exposure absent). Less problematic, but also of concern, was the failure of some participants (∼23%) to consistently report the same number of years in which they were exposed to a weapons category from T1 and T2 (e.g., T1 = 10 years; T2 = 5 years). Factors associated with inconsistent reporting from T1 to T2 included higher GBEV scores, older age, higher number of years in the military, higher number of deployments, and higher blast exposure. This is one of the first studies to comprehensively examine the test-retest reliability of the BETS GBEV. Overall, the test-retest reliability of the GBEV was considered statistically acceptable and provides support for the use of the GBEV in both clinical and research settings. Concerningly, however, substantial inconsistencies were found in the basic reporting of weapons exposure in 33% of the sample that need to be addressed. Future researchers should identify ways to improve the BETS to increase response consistency over time.