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Updated: Jun 23, 2026

Simultaneous Laryngopharyngeal and Conventional Esophageal pH Monitoring
Published on: December 14, 2020
Patterns of laryngopharyngeal and gastroesophageal reflux
1Department of Otolaryngology-Head and Neck Surgery, Kurume University School of Medicine, Kurume, Japan. kimisato@oct-net.ne.jp
Objectives:
Double-probe, 24-hour pH monitoring remains the 'gold standard' for the diagnosis of laryngopharyngeal reflux disease, even though there is no consensus on how to interpret the data collected.
Methods:
Tetra-probe, 24-hour pH monitoring was performed in 56 patients with suspected laryngopharyngeal reflux, in order to investigate patterns of laryngopharyngeal and gastroesophageal reflux.
Results:
The number of reflux episodes and the total and percentage time periods spent with pH < 4.0 were correlated with the distance of the probe from the lower oesophageal sphincter. The number of reflux episodes and the total and percentage time periods with pH < 4.0 were greater when patients were upright (i.e. during the daytime). There were few laryngopharyngeal reflux events recorded for pH levels of <4.0; however, there were a significant number of laryngopharyngeal reflux events recorded for pH levels of <5.0, a level capable of causing laryngopharyngeal reflux disease. When a pH level of <5.0 was used, the number, total time and percentage time of laryngopharyngeal reflux episodes was greater during the supine period (i.e. during sleeping) in a quarter of the cases, compared with results when a pH of <4.0 was used.
Conclusions:
It is valid to use a pH level of 5.0 as indicative of laryngopharyngeal reflux in the hypopharynx.
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