On Pressure Regulation of the Middle Ear

Abstract: The middle ear (ME) pressure is regulated by gas diffusion over the ME mucosa and pressure equalizations via the Eustachian tube (ET). Disturbance in the regulation of ME pressure is believed to contribute to the development of chronic ear diseases. In this work subjects with chronic central perforation (CCP), healthy ears with ventilation tubes (VTs), attic cholesteatoma (AC) and Meniere’s disease (MD) were investigated by measuring the ME pressure directly, continuously and long-term, in combination with ET provocation tests. Pathological conditions were characterised by a negative ME pressure during the daytime measurements, indicating an abnormality in the diffusion of gas from the ME and insufficient ET equalizations.
The MEs of subjects with CCP and healthy ears with VTs were open to the atmosphere before the investigations, which influenced the results, resulting in negative ME pressure during the daytime. These results support the theory that the opening per se, impaired or contributed to the impairment in the ME pressure regulation. Subjects with AC showed negative ME pressure and/or episodes of sniff-induced rapid negative pressure changes during the continuous pressure measurements. These findings indicate a clear relation between the disease and impaired ME pressure regulation. Subjects with MD showed an increased incidence of reduced opening capacity of the ET in provocation tests. This indicates that ME of patients with MD are exposed to pressure situations in daily life exceeding the equilibration capacity of the ET, leading to a possible influence of pressure on the inner ear.
The results of these physiological studies have enhanced our understanding of the regulation of ME pressure in diseased ears. Future studies may elucidate the possibility to complement clinical investigations in chronic ear diseases with the method of continuous, long-term measurement of ME pressure.