Studies of eustachian tube physiology have mainly focused on the ability of the tube to open. For this reason, impaired opening ability has been regarded as the basis of eustachian tube malfunction. Characteristic patterns have been found in pressure measurements in patients with chronic middle ear disease. Simultaneous measurements of nasopharyngeal and middle ear pressures in patients with atelectatic tympanic membranes and retraction cholesteatoma have shown that high negative intratympanic pressure is generated by the voluntary act of sniffing. Eustachian tube malfunction in these patients is thus characterized by failure of the tube to close.