Study of an Oropharyngeal Aerosolized pH Probe for Diagnosing Laryngopharyngeal Reflux (LPR)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00321503
Recruitment Status : Completed
First Posted : May 3, 2006
Last Update Posted : December 9, 2013
Respiratory Technology Corporation
Information provided by (Responsible Party):
Adam Klein, Emory University

May 2, 2006
May 3, 2006
December 9, 2013
May 2006
May 2007   (Final data collection date for primary outcome measure)
Not Provided
Not Provided
Complete list of historical versions of study NCT00321503 on Archive Site
Not Provided
Not Provided
Not Provided
Not Provided
Study of an Oropharyngeal Aerosolized pH Probe for Diagnosing Laryngopharyngeal Reflux (LPR)
Diagnosis and Response to Treatment of Laryngopharyngeal Reflux Using an Oropharyngeal Aerosolized pH Probe
This study is a test of how well a new FDA-approved device is for diagnosing a condition known as laryngopharyngeal reflux (LPR). The device, which measures pH of the air in the upper throat, will be compared to several other methods for diagnosing laryngopharyngeal reflux.

It is estimated that up to 50% of patients with voice disorders and 4-10% of patients seen in otolaryngology practice experience laryngopharyngeal reflux (LPR). LPR has been implicated in the pathogenesis of numerous laryngeal disorders, including subglottic stenosis, laryngeal carcinoma, laryngeal contact ulcers, laryngospasm, and vocal cord nodules. In the pediatric population, it has been associated with asthma, sinusitis, and otitis media. Common symptoms include chronic and intermittent hoarseness, vocal fatigue, globus pharyngeus, cough, postnasal drip, chronic throat clearing, and dysphagia.

Like gastroesophageal reflux disease (GERD), the etiology of LPR is linked to esophageal sphincter dysfunction. In GERD, the lower esophageal sphincter (LES) is involved, whereas in LPR, the pathology results from upper esophageal sphincter (UES) dysfunction. However, diagnosis of LPR is more challenging than that of GERD. The classic reflux-like symptoms of heartburn and regurgitation are often absent in LPR.

The most widely used diagnostic modality for LPR is symptomatic response to treatment, including twice daily proton pump inhibitor (PPI) or H2 blocker therapy for several months. However, the use of a therapeutic modality to make a diagnosis clearly carries disadvantages, including potentially unnecessary exposure to a drug's side effect profile and lengthy time to diagnosis. Another diagnostic instrument is the reflux symptom index (RSI), a validated nine-item questionnaire assessing LPR symptoms. However, LPR symptoms are fairly nonspecific, also appearing in autoimmune and behavior disorders. Lastly, a 24-hour triple-pH probe may be the best objective test diagnosing LPR. However, this method is poorly tolerated by patients and difficulty with ease of administration limits its routine use. To date, we have remained in search of a minimally invasive and specific test for LPR.

In this study, we will investigate the use of a newly developed oropharyngeal pH probe for detecting aerosolized acid as an accurate and minimally invasive diagnostic instrument for LPR. This device has previously been shown to correlate to lower esophageal, upper esophageal, and lower pharyngeal pH as measured by a 24-hour triple channel bifurcated pH probe [ACG Poster session by Dr. G Wiener]. The number of oropharyngeal aerosolized acid reflux events and acid exposure times will be compared to RSI before and after twice daily proton pump inhibitor therapy. In addition, the correlation between acid reflux events and acid exposure times as measured by the Dx probe will be more rigorously compared to that measured by a triple pH probe.

Time Perspective: Prospective
Not Provided
Not Provided
Non-Probability Sample

Pos controls: Subjects visiting the Emory Clinic/Emory Voice center with LPR symptoms.

Neg controls: Random subjects in Atlanta without LPR symptoms. See other descriptions for more details.

Laryngopharyngeal Reflux
Not Provided
Not Provided

*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
Same as current
May 2007
May 2007   (Final data collection date for primary outcome measure)


Group 1 (negative control):

  • RSI ≤ 13
  • No history of voice or swallowing disorders
  • No active voice or swallowing disorders
  • No history of heartburn, regular indigestion, and no prior or current diagnosis of GERD

Groups 2 and 3 (experimental group):

  • Clinical symptoms consistent with LPR as measured by an RSI > 13.
  • No other voice or swallowing pathology on clinical exam


  • Regular treatment with an H2 blocker or proton pump inhibitor (PPI)
  • History of laryngeal/pharyngeal surgery
  • Any planned treatment of the larynx/pharynx other than treatment for LPR
  • Smoking
Sexes Eligible for Study: All
18 Years and older   (Adult, Senior)
Contact information is only displayed when the study is recruiting subjects
United States
DX-1 for LPR ( Other Identifier: other )
Not Provided
Not Provided
Not Provided
Adam Klein, Emory University
Emory University
  • AstraZeneca
  • Respiratory Technology Corporation
Principal Investigator: Adam Klein, MD Dept of Otolaryngology
Study Chair: Michael M Johns, MD Dept of Otolaryngology / Director of Emory Voice Center
Principal Investigator: Leena Khaitan, MD, MPH Dept of Surgery
Study Director: Justin S Golub, BA Emory University
Emory University
December 2013