Sequential motion of the ossicular chain measured by laser Doppler vibrometry

Abstract

Objective: In order to help a surgeon make the best decision, a more objective method of measuring ossicular motion is required.

Methods: A laser Doppler vibrometer was mounted on a surgical microscope. To measure ossicular chain vibrations, eight patients with cochlear implants were investigated. To assess the motions of the ossicular chain, velocities at five points were measured with tonal stimuli of 1 and 3 kHz, which yielded reproducible results. The sequential amplitude change at each point was calculated with phase shifting from the tonal stimulus. Motion of the ossicular chain was visualized from the averaged results using the graphics application.

Results: The head of the malleus and the body of the incus showed synchronized movement as one unit. In contrast, the stapes (incudostapedial joint and posterior crus) moved synchronously in opposite phase to the malleus and incus. The amplitudes at 1 kHz were almost twice those at 3 kHz.

Conclusions: Our results show that the malleus and incus unit and the stapes move with a phase difference.

Chinese abstract

目的：为了帮助外科医生做出最好的决定, 需要一种更客观的测量听小骨运动的方法。

方法：将激光多普勒测振仪安装在手术显微镜上。为了测量听小骨链振动, 研究了8例具耳蜗植入的患者。为了评估听小骨运动, 用1和3kHz的音调刺激测量五点处的速度, 产生可重复的结果。通过由于音调刺激导致的相移来计算每个点处的顺序幅度变化。使用图形应用的平均结果可以视化视网膜链的运动。

结果：锤骨的头部和砧骨的体部显示一体同步运动。相比之下, 镫骨（肋骨关节和后交叉）与锤骨和砧骨呈反相同步移动。 1kHz的幅度几乎是3kHz的幅度的两倍。

结论：我们的研究结果表明, 锤骨和砧骨单元运动和镫骨运动之间相差一个相位。

Keywords:

• Acoustic energy
• laser Doppler vibrometry
• frequency specificity

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by JSPS KAKENHI Grant Number JP16K20247 and KAWAI Foundation for Sound Technology and Music 2016-23.