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Updated: Jun 5, 2026
Simultaneous Laryngopharyngeal and Conventional Esophageal pH Monitoring
Published on: December 14, 2020
Optimisation of the reflux-symptom association statistics for use in infants being investigated by 24-hour pH
Taher I Omari1, Andrea Schwarzer, Michiel P vanWijk
1Gastroenterology Unit, Children, Youth, and Women's Health Service, North Adelaide, Australia. taher.omari@adelaide.edu.au
Insights
Optimizing pH-impedance monitoring for infants with GERD, this study found that standard time intervals are suitable for cough and regurgitation. However, a longer 5-minute interval is recommended for assessing crying to improve symptom association probability (SAP) accuracy.
Area of Science:
- Pediatric Gastroenterology
- Diagnostic Technology
Background:
- pH-impedance monitoring is key for diagnosing gastroesophageal reflux (GER) using symptom association probability (SAP).
- Existing SAP criteria are optimized for adult heartburn, not infant GER disease symptom profiles.
- Infant GERD requires tailored diagnostic criteria for accurate SAP calculation.
Purpose of the Study:
- To optimize the criteria for calculating symptom association probability (SAP) in infants with GER disease.
- To adapt current pH-impedance monitoring guidelines for a pediatric population.
- To improve the diagnostic accuracy of GER in infants.
Main Methods:
- Ten infants with symptomatic reflux underwent 48-hour pH-impedance monitoring.
- Cough, crying, and regurgitation were logged, and reflux episodes were identified.
- Symptom association probability (SAP) was calculated using adjustable time windows (15-600 seconds) for day-to-day agreement analysis.
Main Results:
- No significant day-to-day difference was observed in the number of reflux or symptom episodes.
- Optimal SAP agreement was achieved with 2-minute intervals for cough, 5 minutes for crying, and 15 seconds to 5 minutes for regurgitation.
- Standard 2-minute intervals showed good agreement for cough and regurgitation but poor agreement for crying.
Conclusions:
- The standard 2-minute time interval is appropriate for analyzing cough and regurgitation in infant GERD.
- A 5-minute time interval is recommended for assessing crying to enhance the reliability of SAP calculations in infants.
- Adjusting time windows in pH-impedance monitoring improves diagnostic accuracy for infant GERD symptoms.
Background And Aim:
pH-impedance monitoring is used to diagnose symptomatic gastroesophageal reflux (GER) based on symptom association probability (SAP). Current criteria for calculation of SAP are optimised for heartburn in adults. Infants, however, demonstrate a different symptom profile. The aim of the present study was to optimise criteria for calculation of SAP in infants with GER disease.
Patients And Methods:
Ten infants referred for investigation of symptomatic reflux were enrolled. GER episodes were recorded using a pH-impedance probe, which remained in place for 48 hours. During the test, cough, crying, and regurgitation were marked. Impedance recordings were analysed for the occurrence of bolus reflux episodes. SAP for behaviors following reflux episodes was separately calculated for day 1 and day 2 using automated reporting software, which enabled the time window used for SAP calculations to be modified from 15 to 600 seconds. Day-to-day agreement of SAP was assessed by calculating the 95% limits of agreement (mean difference ± 1.96 standard deviations of differences) and their confidence intervals.
Results:
The number of bolus GER episodes and symptom episodes reported did not differ from day to day. The best agreement in SAP between the 2 days was found using time intervals of 2 minutes for cough, 5 minutes for crying, and 15 seconds and/or 2 to 5 minutes for regurgitation.
Conclusions:
We conclude that the standard 2-minute time interval is appropriate for the investigation of cough and regurgitation symptoms. The day-to-day agreement of SAP for crying was poor using standard criteria, and our results suggest increasing the reflux-symptom association time interval to 5 minutes.
