1.   Several studies have shown the association of reflux oesophagitis with lower oesophageal sphincter dysfunction and impaired oesophageal peristalsis.

2.   The contractions occurring during episodes of recurrent autonomous oesophageal peristalsis were preceded by a small pressure plateau in four of the five patients.

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

4.   Our aims in this study were to assess in PSS patients, with or without impaired oesophageal peristalsis, acid clearance by the oesophagus and oesophageal sensitivity to acid.

5.   In summary, our studies of unselected patients with PSS show that impaired oesophageal peristalsis delays the clearance of acid and increases the exposure time to acid.