Eeg-Olofsson Måns, Stenfelt Stefan, Tjellström Anders, Granström Gösta
Department of Clinical and Experimental Medicine/Division of Technical Audiology, Linköping University, Linköping, Sweden.
Int J Audiol. 2008 Dec;47(12):761-9. doi: 10.1080/14992020802311216.
One limitation with the Bone Anchored Hearing Aid (Baha) is too poor amplification for patients with moderate to severe sensorineural hearing losses. Therefore, we investigated if bone conducted (BC) sound transmission improves when the stimulation approaches the cochlea. Also the influence from the squamosal suture on BC sound transmission was investigated. Both sides of the heads on seven human cadavers were used and vibrational stimulation was applied at eight positions on each side with a frequency range of 0.1-10 kHz. A laser Doppler vibrometer was used to measure the resulting velocity of the cochlear promontory. It was found that the velocity of the promontory increases as the stimulation position approaches the cochlea; this was especially apparent at distances within 2.5 cm from the ear canal opening and when the stimulation position was in the opened mastoid. At frequencies above 500 Hz there was on average 10 to 20 dB greater vibrational response at the cochlea when the stimulation was close to the cochlea compared with the normal Baha position. Moreover, even if there were general indications of attenuation of BC sound when passing the squamosal suture, an effect from the suture could not be conclusively determined.
骨锚式助听器（Baha）的一个局限性在于，对于中重度感音神经性听力损失患者，其放大效果太差。因此，我们研究了当刺激接近耳蜗时骨传导（BC）声音传输是否会改善。同时还研究了鳞状缝对BC声音传输的影响。使用了7具人类尸体头部的两侧，并在每侧的8个位置施加频率范围为0.1 - 10 kHz的振动刺激。使用激光多普勒振动计测量耳蜗岬的最终速度。结果发现，随着刺激位置接近耳蜗，岬的速度增加；这在距耳道开口2.5厘米以内的距离以及刺激位置位于开放乳突时尤为明显。在高于500 Hz的频率下，与正常Baha位置相比，当刺激靠近耳蜗时，耳蜗处的振动响应平均大10至20 dB。此外，即使在通过鳞状缝时BC声音有普遍的衰减迹象，但无法最终确定该缝的影响。
