1.   Reflux symptoms lasted longer in patients with prolonged oesophageal acid exposure but were still reported for a small fraction of the total acid exposure time.

2.   We speculated therefore that oesophageal sensitivity to acid would be reduced in PSS patients with impaired oesophageal peristalsis.

3.   We also studied oesophageal sensitivity to acid during acid perfusion test and overnight pH monitoring.

4.   Our hypothesis was that the oesophageal sensitivity to acid would be reduced in PSS with aperistalsis on the basis of changed oesophageal sensory pathways.

5.   Thus, oesophageal sensitivity to acid was preserved in our patients.