assess the incidence of the entire spectrum of esophageal disorders and possible theories for overlap in IBS patients using different diagnostic modalities.

In the practice of a gastroenterologist, irritable bowel syndrome (IBS) is the most frequent functional disorder. Its prevalence in the population is 9.8%-12.8%. Its frequency in women is more than men. In some studies, it has been shown that a patient may have an overlap of symptoms of different functional diseases of the gastrointestinal tract. Different researchers have ambiguously assessed the frequency of occurrence of esophageal disorders in patients with IBS. So, based on the publications of different authors, they are found in 15-80% of cases. In a study by N. de Bortoli et al. (2016) noted the association of IBS with functional heartburn in 77% of cases, and with GERD and hypersensitive esophagus (called heartburn associated with reflux) - in 33% of cases.

Traditionally, diagnostics of a combination of functional disorders of the esophagus and intestines were based on data X-ray and endoscopic methods. However modern research has shown the importance of using in this group of patients with daily combined pH impedance measurement. Thus, many authors have noted the undoubted advantages of this method in the diagnosis of esophageal disorders. Unfortunately, works devoted to this topic, extremely few in number, and the information obtained in them is quite contradictory, which indicates the need to continue research in this direction.

Inclusion Criteria:

• Established diagnosis of IBS (according to the Rome criteria of the III revision).
• Upper GIT symptoms in the form of heartburn (sometimes belching), a lump in the throat, and non-cardiac chest pain.

Exclusion Criteria:

• History of thoracic, esophageal, or gastric surgery.
• Presence of duodenal or gastric ulcer on upper endoscopy.
• Presence of duodenal or gastric cancer on upper endoscopy.
• Conditions that prevent the installation of a nasogastric tube (nasopharyngeal formation, severe lumen-facial trauma).
• mental disorders state and disability.
• Pregnancy and breastfeeding.