Key Question 3: To what extent do blast-exposed Veterans resemble older listeners and participants with mild TBI who have not been exposed to blasts in their performance on CAP tests and functional tests of hearing? It is hypothesized that comparisons of the blast-exposed group with an older group with matched pure-tone sensitivity and an age- and hearing-matched group with non-blast-related TBI will be consistent with premature aging in the blast-exposed group but demonstrate substantive differences with the non-blast group.