OBJECTIVES: To confirm feasibility of transnasal placement of a wireless pH-monitoring capsule in the upper esophagus, and to determine the positive predictive value of LPR and GERD signs and symptoms for diagnosis of LPR in patients with OSAHS. STUDY DESIGN: Prospective. nonrandomized, IRB-approved study of 89 OSAHS patients with and without symptoms and signs of LPR. METHODS: After complete history including QOL survey and fiberoptic laryngoscopy, patients underwent transnasal placement of the pH-monitoring capsule and wireless data collection for 24 hours. RESULTS: 77 of 89 consecutive patients underwent successful placement of wireless pH-monitoring capsule (86.5% success rate) and completed the study. 55 (71.4%) OSAHS patients had positive pH studies. 10.4% of these patients reported no symptoms or signs of LPR, indicating occult disease. CONCLUSION: Success rates of placement, tolerability, morbidity. and complications are excellent. Wireless upper esophageal pH monitoring is safe and effective for diagnosing LPR in patients with OSAHS. (c) 2007 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.