A non-randomised, prospective study to assess the effects of beta-blockers on substance P levels and the swallowing function. The study is going to be carry out in the Gastrointestinal Physiology Laboratory of the Hospital de Mataró (Spain). All participants will be actively recruited from a Linked hospital and primary care database. We include two groups: the first group (group 1) are participants taking beta-blockers and the second group (group 2) are participants not-taking beta-blockers.

Inclusion Criteria:

- Patients taking and not taking beta-blockers

Exclusion Criteria:

• Participants with heat and neck or esophageal cancer
• Participants with stroke or neurological disease
• Participants with central nervous system disease
• Participants with concomitant treatment with Angiotensin converting enzyme inhibitors (ACEI), Angiotensin II receptor antagonists (ARA-II), Antipsychotics, Dopamine agonists, Capsaicine.
• Participants with severe clinical signs of aspiration, including oxygen desaturation ≥3%.

All population.