Gastroesophageal reflux: update on pathogenesis and diagnosis.

The study of GER has been hindered by the lack of a good animal model and by the presence of some reflux in all normal individuals. By the painstaking process of studying normal infants, children, and adults, it is becoming evident that abnormalities of acid clearance, especially in the recumbent position (or during sleep), may be critical to an understanding of this disorder. As more is learned about the conditions surrounding "normal" reflux, it will be possible to refine the techniques of diagnosis and thereby identify the abnormal with more security.