Ambulatory 24-h oesophageal impedance-pH recordings: reliability of automatic analysis for gastro-oesophageal reflux assessment

Neurogastroenterol Motil. 2006 Nov;18(11):978-86. doi: 10.1111/j.1365-2982.2006.00825.x.


Oesophageal pH-impedance monitoring allows detection of acid and non-acid gastro-oesophageal reflux (GOR) events. Visual analysis of impedance recording requires expertise. Our aim was to evaluate the efficacy of an automated analysis for GOR assessment. Seventy-three patients with suspected GORD underwent 24-h oesophageal pH-impedance monitoring. Recordings analysis was performed visually (V) and automatically using Autoscan function (AS) of Bioview software. A symptom index (SI) > or =50% was considered for a significant association between symptoms and reflux events. AS analysis detected more reflux events, especially non-acid, liquid, pure gas and proximal events. Detection of oesophageal acid exposure and acid reflux events was similar with both analyses. Agreement between V and AS analysis was good (Kendall's coefficient W > 0.750, P < 0.01) for all parameters. During pH-impedance studies, 65 patients reported symptoms. As compared to visual analysis, the sensitivity and specificity of a positive SI determined by AS were respectively 85.7% and 80% for all reflux events, 100% and 98% for acid reflux and 33% and 87.5% for non-acid reflux. Despite good agreement with visual analysis, automatic analysis overestimates the number of non-acid reflux events. Visual analysis remains the gold standard to detect an association between symptoms and non-acid reflux events.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Automation
  • Esophageal pH Monitoring*
  • Female
  • Gastroesophageal Reflux / diagnosis*
  • Humans
  • Male
  • Middle Aged
  • Plethysmography, Impedance
  • Sensitivity and Specificity
  • Software*