Table 1.

Operational definitions of blast variables.

Variable	Data source	Type	Operational definition	Symptom sample	Cognitive sample
Blast TBI	MMA-TBI	Dichotomous	TBI with blast present as one potential concussive mechanism. This includes TBI with mixed blast and blunt mechanisms	n = 95	n = 85
Primary blast TBI	MMA-TBI	Dichotomous	Presence of at least one TBI for which blast was the only mechanism present. May include individuals with additional history of blunt TBI	n = 76	n = 68
Pressure severity	SBI	Continuous	Maximum reported severity of exposure to a pressure wave. The experienced pressure gradient of each blast event is rated by a participant on a given a behaviorally anchored Likert scale	Mean = 1.8 SD = 1.5	Mean = 1.9 SD = 1.5
Distance	SBI	Dichotomous	Distance ≤3 meters and ≤10 meters. This variable is positive if the participant reported any blast exposure below the noted threshold	3 meters n = 65 10 meters n = 111	3 meters n = 62 10 meters n = 105
Frequency	SBI	Continuous	Total lifetime number of reported exposures to blast, defined as experiencing any pressure gradient, defined as a score >0 on the SBI pressure scale	Mean = 169.3 SD = 575.4	Mean = 182.9 SD = 593.7

TBI, traumatic brain injury; MMA-TBI, Mid-Atlantic MIRECC Assessment of TBI; SBI, Salisbury Blast Interview.All TBI in this sample were mild in severity.