[1] Univ Alabama, Dept Commun Disorders, Tuscaloosa, AL 35487 USA
[2] Brigham & Womens Hosp, Neonatal Intens Care Unit, 75 Francis St, Boston, MA 02115 USA
[3] Johns Hopkins Sch Med, Dept Pediat Otolaryngol Head & Neck Surg, Baltimore, MD USA
[4] Johns Hopkins Sch Med, Dept Phys Med & Rehabil, Baltimore, MD USA
[5] Med Coll Wisconsin, Pediat Gastroenterol Hepatol & Nutr, Wauwatosa, WI USA