Ghoncheh Mohammad, Lilli Giorgio, Lenarz Thomas, Maier Hannes
Department of Otolaryngology and Institute of Audioneurotechnology (VIANNA), Hannover Medical School, Hannover, Germany.
Department of Otolaryngology and Institute of Audioneurotechnology (VIANNA), Hannover Medical School, Hannover, Germany; Cluster of Excellence Hearing4all, Germany.
Hear Res. 2016 Oct;340:161-168. doi: 10.1016/j.heares.2015.12.019. Epub 2015 Dec 23.
The intraoperative and postoperative objective functional assessment of transcutaneous bone conduction implants is still a challenge. Here we compared intraoperative Laser-Doppler-vibrometry (LDV, Polytec Inc.) to measure vibration of the bone close to the implant to Outer Ear Canal Sound Pressure Level (OEC-SPL) measurements. Twelve single sided deafness (SSD) patients with contralateral intact ossicular chains and eight bilateral conductive hearing loss (CHL) patients were included in the study. SSD patients had a minor average air-bone-gap (ABG) of 0.4 ± 0.4 dB (0.5, 1, 2, 4 kHz mean value (MV) ± standard deviation (SD)) on the contralateral side where a normal transmission between cochlea and the tympanic membrane can be assumed. CHL patients had an impaired middle ear transmission with a mean ABG of 46.0 ± 7.9 dB (MV±SD). Vibration and OEC-SPL responses could reliably be recorded with a minimal signal-to-noise ratio of at least 12 dB. Average OEC-SPL on the contralateral side and intraoperative vibration measurements were strongly correlated in SSD (r = 0.75) and CHL (r = 0.86) patients. The correlation in individual results between OEC-SPL and vibration measurements was weak, indicating some underlying inter-individual variability. The high correlation of average responses showed that OEC-SPL are closely linked to bone vibration, although both cannot be equivalently used for intraoperative testing due to the high variability in individual results. On the other hand, OEC-SPL provides an easy and affordable measurement tool to monitor stability and functionality postoperatively using individual reference measurements. We observed no significant differences (t-test, p < 0.05) by comparing results from contralateral OEC-SPL in twelve SSD and eight CHL patients at frequencies between 0.5 and 8 kHz. This implies that the part of the measured sound pressure in the ear canal originating from the cochlea and emitted by the tympanic is not dominant and OEC-SPL is mainly due to vibration of the external ear-canal walls as the only other pathway of BC sound to reach the ear canal. In addition, the transcranial attenuation (contralateral outer ear canal sound pressure divided by ipsilateral) was compared to previous studies measuring vibration by LDV and accelerometer. The trend in the average transcranial attenuation in patients was similar to previous studies measuring the OEC-SPL with less than 5 dB difference.
经皮骨传导植入物的术中及术后客观功能评估仍是一项挑战。在此，我们将术中使用激光多普勒振动测量仪（LDV，Polytec公司）测量植入物附近骨骼的振动与外耳道声压级（OEC-SPL）测量进行了比较。该研究纳入了12名单侧耳聋（SSD）患者，其对侧听骨链完整，以及8名双侧传导性听力损失（CHL）患者。SSD患者对侧的平均气骨导差（ABG）较小，为0.4±0.4 dB（0.5、1、2、4 kHz平均值（MV）±标准差（SD）），在该侧可假定耳蜗与鼓膜之间的传输正常。CHL患者中耳传输受损，平均ABG为46.0±7.9 dB（MV±SD）。振动和OEC-SPL反应能够以至少12 dB的最小信噪比可靠记录。SSD患者对侧的平均OEC-SPL与术中振动测量结果高度相关（r = 0.75），CHL患者中也是如此（r = 0.86）。OEC-SPL与振动测量的个体结果之间的相关性较弱，表明存在一些个体差异。平均反应的高度相关性表明，OEC-SPL与骨骼振动密切相关，尽管由于个体结果的高度变异性，两者不能等效用于术中测试。另一方面，OEC-SPL提供了一种简单且经济的测量工具，可通过个体参考测量在术后监测稳定性和功能。通过比较12名SSD患者和8名CHL患者在0.5至8 kHz频率下对侧OEC-SPL的结果，我们未观察到显著差异（t检验，p < 0.05）。这意味着耳道内测量的声压中源自耳蜗并由鼓膜发出的部分并不占主导，OEC-SPL主要是由于外耳道壁的振动，这是骨传导声音到达耳道的唯一其他途径。此外，将经颅衰减（对侧外耳道声压除以同侧）与之前使用LDV和加速度计测量振动的研究进行了比较。患者平均经颅衰减的趋势与之前测量OEC-SPL的研究相似，差异小于5 dB。
