If gastric juice refluxes back into the oesophagus and up into the throat/pharynx/mouth area, causing discomfort or injury, this is known as reflux disease (reflux). Classic symptoms include a burning pain in the middle of the upper abdomen, chest or throat (so-called heartburn), regurgitation of food (acid regurgitation), foreign body sensation in the throat area. There are also changes in the voice, hoarseness, difficulty clearing the throat, difficulty swallowing or a dry, irritating cough due to the chemical irritation of the vocal folds by the gastric juice. There are various causes of reflux. Often there is a weakness of the lower oesophageal sphincter or a hiatal hernia, which favours the reflux of gastric juice. Sometimes there are also movement disorders in the oesophagus or stomach with insufficiently efficient transport of food and liquids.

After a consultation with a specialist, three further standard examinations are ordered as a matter of priority for a proper reflux diagnosis:

• Gastroscopy: a tube-shaped camera can be used to view the mouth, pharynx, throat, oesophagus, stomach and the beginning of the duodenum and, if necessary, small tissue samples can be taken.
• Oesophageal manometry: A pressure measurement of the oesophagus can detect movement disorders or a malfunction of the oesophagus and sphincter.
• 24-hour impedance pH measurement: A small tube is placed in the oesophagus through the nose and left there for 24 hours. The probe measures how often gastric juice flows back to a certain level and how acidic this juice is.

These examinations allow reflux to be definitively diagnosed, possible causes to be identified, any further investigations to be considered and the best possible treatment to be suggested.

In these times of rapidly advancing digitalisation and increasing technical possibilities, we ask ourselves the following: If reflux changes the voice - would it be possible to detect reflux disease with voice samples the other way round? Studies are already underway in several other medical fields that are successfully analysing voice and speech samples and looking for typical changes in the voice pattern for diseases.

Our theory: Alterations typical for reflux can be found in voice samples. In future, voice samples can be used as a harmless, simple and inexpensive initial assessment for reflux.

The questions of our research project are therefore:

1. Do patients with confirmed reflux have a typical pattern of changes in their voice?
2. Can these changes be reliably determined via voice analyses?
3. Could a simple voice sample become the first basic examination for reflux patients in the future?

Procedure and duration of the study:

This project will be conducted exclusively at the Inselspital Bern (monocentric = 1 hospital, national = 1 country). All persons who receive the above-mentioned standard examination for a reflux clarification are eligible for participation. The standard examination will either confirm or rule out reflux. For our research project, we want to investigate two situations:

1. firstly, as a baseline, we would like to examine the voices of 47 participants with confirmed reflux and compare them with the voices of 47 participants with confirmed absence of reflux disease.
2. secondly, we would like to check the voices of participants with confirmed reflux again 5 months after the start of treatment and compare them with their initial situation.

Participants will complete a questionnaire and provide a voice sample (short simple recording into a microphone). Participation in the research project does not require any additional hospital visits or consultation appointments and lasts a maximum of 5 months.

The voice samples are then digitised, analysed, evaluated and searched for typical patterns of change by us in collaboration with the CSEM Neuchâtel (Centre Suisse Électronique et de Microtechnique). CSEM is an internationally recognised Swiss technology innovation centre that will help us with the sophisticated evaluation of the voice analyses. As these are simple voice recordings into a microphone, there are no additional clarifications, interventions or risks involved in participating. Data will be stored in encrypted form in a SharePoint database in strict compliance with all data protection regulations and will only be used for the agreed research project. Results are expected in 2025.

Inclusion Criteria:

• Age above 18
• Informed consent
• Undergoing gastroesophageal reflux diagnostic according to the current standard
• Basic reading skills in German or English

Exclusion Criteria:

• Age below 18
• No basic reading skills in German or English
• Diseases with altered voice
• Laryngopharyngeal surgery or interventions in the past

We include patients undergoing GERD diagnostic with esophagogastroduodenoscopy plus biopsies, high-resolution manometry and 24-hour impedance-pH-metry, according to the todays standard in reflux diagnostics, in the Bauchzentrum of University Hospital Bern Inselspital. After this standardized examination, there will be patients with confirmed gastroesophageal reflux disease as well as patients with confirmed absence of a GERD. Out of these patients, we collect N=47 patients with confirmed gastroesophageal reflux disease (GERD-Group) and N=47 patients with confirmed absence of gastroesophageal reflux disease as a control group (Non-GERD-Group).

There is not a plan to make IPD available