Objective The goal of the present study was to determine the effects of different location perfora-tions on the middle ear transfer functions by measuring the velocity and pattern of the tympanic membrane vibration in guinea pigs with intact and perforated TM .Methods A laser Doppler vibrometer was used to measure the sound transmission properties on the movement of the tympanic membrane on 6 fresh temporal bones of guinea pigs in the frequency range of 0 .5~8 kHz at 90 dB SPL .The velocity was measured at three points on the manubrium before and after a different location perforation was made with a 20-gauge needle(1 .1 mm diameter) .The locations of the perforations were in anterior -inferior quadrants of left ears and in posterior -inferior quadrants of right ears .And the velocity was measured from 6 poins with the intact tympanic membrane .Results The highest velocities were re-corded at the site of inferior umbo throughout the frequency range .The manubrium vibration velocity losses were noted in the perforated ears below 1 .5 kHz ,the velocity losses were smaller above 1 .5 kHz ,and the maximum ve-locity loss was about 7 dB at 500 Hz with the posterior -inferior quadrant perforation .Although there was a trend for anterior-inferior perforations to show a slighter loss than posterior -inferior perforations in velocity below 1 .5 kHz ,no statistical differences in velocity loss were found between different perforations .The average ratio of short process velocity to umbo velocity at all frequencies was approximately 0 .5 ,and the ratios were found no systematic differences before and after perforation at almost all frequencies from different perforations .Conclusion The manu-brium vibration velocity losses from TM perforation are frequency -dependent and the largest losses occur at the lowest sound frequencies .Different sites of small perforation have not any important effects on middle ear sound transmission .%目的：通过观察豚鼠鼓膜不同位点的振动情况及穿孔前后锤骨柄不同位点的振动改变情况，初步探讨鼓膜穿孔对中耳传音机制的影响。方法采用6只新鲜豚鼠颞骨标本，采用直径1．1 mm的静脉留置针穿刺左耳鼓膜前下方和／或右耳鼓膜后下方并旋转一周造孔；于鼓膜造孔前后给予强度为90 dB SPL、0．5～8 kHz共14个频率的声刺激，利用激光多普勒振动仪检测系统测量完整鼓膜不同位点的振动速度及不同位置鼓膜穿孔前后锤骨柄不同位点的振动速度。完整鼓膜上六个测量位点分别为锤骨柄上的脐部、锤骨中部、短突及鼓膜紧张部上锤骨柄内侧、外侧、下部的三个点。结果完整鼓膜所测六个位点中位于脐部下方的位点振动速度最大。鼓膜穿孔前后脐部振动的频率响应曲线的形状基本相似，1．5 kHz以下频率范围内振动损失较明显，1．5 kHz以上频率范围内振动损失减轻甚至增加。鼓膜后下方穿孔后0．5 kHz频率处脐部振动损失最大，损失值为7 dB。1．5 kHz以下频率范围内鼓膜后下方穿孔引起的脐部振动损失比前下方穿孔大，但差异无统计学意义。在所测频率范围内锤骨短突与鼓膜脐部振动速度之比的均值均为0．5，鼓膜穿孔对这一比值未造成明显影响，不同部位鼓膜穿孔的影响也无统计学差异。结论鼓膜穿孔对鼓膜振动所造成的损失有频率依赖性，频率越低损失越严重。不同位置的鼓膜小穿孔对其传音功能的影响无统计学差异。
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