[1] Univ Pittsburgh, Pulm Allergy Crit Care & Sleep Med, Med Ctr, Pittsburgh, PA USA
[2] Togus VA Med Ctr, Augusta, ME USA
[3] Pittsburgh VA Med Ctr, Pittsburgh, PA USA
[4] San Francisco VA Hlth Care Syst, Med, San Francisco, CA USA
[5] Oregon Hlth & Sci Univ, Portland, OR USA
[6] Natl Ctr Rehabilitat Auditory Res, Portland, OR USA
[7] UCLA, Pulm, Sch Med, Los Angeles, CA USA
[8] UPMC, VA Pittsburgh Healthcare Syst, Pulm Allergy Crit Care & Sleep Med, Pittsburgh, PA USA