Mechanics of the middle ear system: Age-related changes in viscoelastic properties

Morphological studies of age-related changes in the tympanic membrane have suggested a decreased elasticity for increasing age, whereas age-related changes in admittance measured by tympanometry have revealed inconsistent results. In this study we report on the viscoelastic properties of the middle ear system by means of a new method in two different age groups, This method measures hysteresis (mu J), which describes the viscous properties of the system, and compliance (mm(3)/kPa) reflecting its elasticity, Moreover, P-ec0 (kPa) was recorded, which corresponds to middle ear pressure measured by tympanometry, Recordings were made in a group of 30 older normal subjects (mean age 77 years) and results were compared to previous findings in a group of 39 younger normal subjects (mean age 29), Hysteresis was markedly decreased in the older normal group compared to the younger one (p = 0.057), This may reflect morphological changes previously reported in the tympanic membrane and can be related to theoretical considerations on tympanic membrane rupture pressures. Compliance and P-ec0 were not influenced by variation in age (p = 0.645 and 0.966), Copyright (C) 2000 S. Karger AG, Basel.