Figure 2 Raw data showing cross sectional area, pressure, and sensory rating (scale not shown) in a typical patient with oesophagitis (A) and a healthy control subject (B). The sensation was rated continuously on a visual analogue scale during distension of the oesophagus with a bag at 25 ml/min using an infusion pump. At moderate pain the pump was reversed and fluid withdrawn. The patient tolerated higher mechanical stimulus intensity compared with the control subject, as reflected in the higher cross sectional area and longer infusion time (higher volume).