School of Aerospace and Mechanical Engineering, University of Oklahoma, 865 W. Asp Ave., Norman, OK, 73019, USA.
J Assoc Res Otolaryngol. 2020 Oct;21(5):395-407. doi: 10.1007/s10162-020-00765-0. Epub 2020 Aug 11.
Mechanical properties of the tympanic membrane (TM) play an important role in sound transmission through the middle ear. While numerous studies have investigated the mechanical properties of the adult human TM, the effects of age on the TM's properties remain unclear because of the limited published data on the TM of young children. To address this deprivation, we used baboons in this study as an animal model for investigating the effect of age on the mechanical properties of the TM. Temporal bones were harvested from baboons (Papio anubis) of four different age groups: less than 1 year, 1-3 years, 3-5 years, and older than 5 years of age or adult. The TM specimens were harvested from baboon temporal bones and cut into rectangle strips along the inferior-superior direction, mainly capturing the influence of the circumferential direction fibers on the TM's mechanical properties. The elasticity, ultimate tensile strength, and relaxation behavior of the baboon TM were measured in each of the four age groups with a mechanical analyzer. The average effective Young's modulus of adult baboon TM was approximately 3.1 MPa, about two times higher than that of a human TM. The Young's moduli of the TM samples demonstrated a 26 % decrease from newborn to adult (from 4.2 to 3.1 MPa). The average ultimate tensile strength of the TMs for all the age groups was ~ 2.5 MPa. There was no significant change in the ultimate tensile strength and relaxation behavior among age groups. The preliminary results reported in this study provide a first step towards understanding the effect of age on the TM mechanical properties from young to adult.
鼓膜（TM）的力学性能在中耳传音中起着重要作用。虽然已有大量研究探讨了成人 TM 的力学性能，但由于关于幼儿 TM 的资料有限，年龄对 TM 性能的影响仍不清楚。为了解决这一不足，我们在这项研究中使用狒狒作为研究 TM 年龄相关力学性能的动物模型。我们从四个不同年龄段的狒狒（Papio anubis）中获取颞骨：小于 1 岁、1-3 岁、3-5 岁和 5 岁以上或成年。从狒狒颞骨中取出 TM 标本，沿下-上方向切成矩形条带，主要捕捉周向纤维对 TM 力学性能的影响。在四个年龄段中的每个年龄段，我们使用机械分析仪测量狒狒 TM 的弹性、极限拉伸强度和松弛行为。成年狒狒 TM 的平均有效杨氏模量约为 3.1MPa，约为人类 TM 的两倍。从新生儿到成年，TM 样本的杨氏模量降低了 26%（从 4.2 到 3.1MPa）。所有年龄段的 TM 的平均极限拉伸强度约为 2.5MPa。各年龄段的极限拉伸强度和松弛行为均无明显变化。本研究初步结果为了解从幼年到成年 TM 力学性能的年龄影响提供了第一步。
