Murakoshi Michio, Yoshida Naoto, Sugaya Mitsuki, Ogawa Yudai, Hamanishi Shinji, Kiyokawa Hiromichi, Kakuta Risako, Yamada Masaaki, Takahashi Ritsuko, Tanigawara Shingo, Matsutani Sachiko, Kobayashi Toshimitsu, Wada Hiroshi
Department of Bioengineering and Robotics, Tohoku University, Sendai, Japan.
Int J Pediatr Otorhinolaryngol. 2013 Apr;77(4):504-12. doi: 10.1016/j.ijporl.2012.12.020. Epub 2013 Jan 9.
Early diagnosis and treatment of hearing disorders in neonates is highly effective for realization of linguistic competence and intellectual development. To objectively and quickly evaluate the dynamic characteristics of the middle ear, a sweep frequency impedance (SFI) meter was developed, which allowed the diagnosis of middle-ear dysfunctions in adults and children. However, this SFI meter was not applicable to neonates since the size of the measurement probe was too large. In the present study, therefore, the SFI meter was improved, i.e., the diameter of the probe was reduced to that of the neonatal external ear canal. By using this newly designed SFI meter, SFI tests were performed in healthy neonates.
A sound of the sweeping sinusoidal frequency between 0.1 kHz and 2.0 kHz in 0.02-kHz step intervals is presented to the ear canal by an SFI probe while the static pressure of the ear canal is kept constant. During this procedure, the sound pressure level (SPL) is measured. The measurements are performed at 50-daPa intervals of static pressure from 200 daPa to -200 daPa.
Measurements were conducted in 10 ears of 9 neonates. The SPL showed two variations at 0.26 ± 0.03 kHz and 1.13 ± 0.12 kHz. Since the SPL is known to show a variation at frequencies from 1.0 kHz to 1.6 kHz due to the resonance of the middle ear in adults and children with normal hearing, the second variation is probably related to such resonance in neonates. The measurement of gel models, which mimics the neonatal external ear canal, showed a variation in SPL at around 0.5 kHz. This implies that the source of the first variation may possibly be related to the resonance of the external ear canal wall.
SFI tests revealed that there were two variations in the SPL curve in neonates, one at 0.26 ± 0.03 kHz and the other at 1.13 ± 0.12 kHz, the former and the latter being possibly related to the resonance of the external ear canal wall and that of the middle ear, respectively. This result suggests that the dynamic characteristics of the middle ear in neonates are different from those in adults.
新生儿听力障碍的早期诊断和治疗对于其语言能力和智力发育的实现非常有效。为了客观快速地评估中耳的动态特性，开发了一种扫频阻抗（SFI）仪，它可用于诊断成人和儿童的中耳功能障碍。然而，这种SFI仪不适用于新生儿，因为测量探头尺寸太大。因此，在本研究中对SFI仪进行了改进，即将探头直径减小到新生儿外耳道的直径。使用这种新设计的SFI仪，对健康新生儿进行了SFI测试。
通过SFI探头向耳道施加频率在0.1 kHz至2.0 kHz之间、步长间隔为0.02 kHz的扫频正弦波声音，同时保持耳道静压恒定。在此过程中，测量声压级（SPL）。测量在200 daPa至 -200 daPa的静压下以50 daPa的间隔进行。
对9名新生儿的10只耳朵进行了测量。声压级在0.26±0.03 kHz和1.13±0.12 kHz处出现两个变化。由于已知在听力正常的成人和儿童中，声压级会因中耳共振在1.0 kHz至1.6 kHz频率处出现变化，所以第二个变化可能与新生儿的这种共振有关。对模拟新生儿外耳道的凝胶模型进行测量，结果显示在约0.5 kHz处声压级有变化。这意味着第一个变化的来源可能与外耳道壁的共振有关。
SFI测试显示，新生儿声压级曲线存在两个变化，一个在0.26±0.03 kHz，另一个在1.13±0.12 kHz，前者和后者可能分别与外耳道壁的共振和中耳的共振有关。这一结果表明，新生儿中耳的动态特性与成人不同。
