Marcelli Emanuela, Cavallari Paolo, Frigerio Alice, Colletti Giacomo, Biglioli Federico, Fanti Roberta, Plicchi Gianni, Cercenelli Laura
Biomedical Technology Unit, University of Bologna, 40138 Bologna, Italy.
Int J Artif Organs. 2013 Mar;36(3):195-202. doi: 10.5301/ijao.5000178. Epub 2013 Feb 28.
We present an innovative method to quantify the eyeblink by using a miniature gyroscopic sensor (gyro), which is applied on the upper eyelid. Electrical Stimulation (ES) of the facial nerve is a promising technology to treat dysfunctional eyelid closure following facial paralysis. We used the new gyro-based method to evaluate the biomechanics of both the spontaneous and the ES-induced eyeblink, and to identify the best ES protocol.
During blinking, eyelids rotate about the axis passing through the eye canthi, thus we propose to use a gyro for measuring the angular velocity of the upper eyelid (ωe ). The angular displacement of the eyelid (θe ) was calculated by integrating the ωe signal. Two indices were derived from θe: 1) the eyelid angular displacement during eye closure (C), calculated as the peak value of θe ; 2) the eyelid closure duration (D), calculated as the time interval between zero signal and the peak value of θe. In a healthy volunteer we used this method to quantify both the spontaneous eyeblink and the blinks elicited by different ES patterns.
For the spontaneous eyeblink, indices C = 14.0 ± 1.8° and D = 94.0 ± 10.8 ms were computed. By comparing C and D indices for spontaneous and ES cases, trains of 10 pulses with a frequency ranging from 200 Hz to 400 Hz proved to induce the most effective and natural-like eyeblinks.
The new gyro-based method proved to be a valuable tool to provide dynamic and real-time quantification of eyelid motions. It could be particularly useful for evaluating the effective and natural-like eyeblink restoration provided by ES.
我们提出一种创新方法，通过使用安装在上眼睑的微型陀螺仪传感器（陀螺仪）来量化眨眼。面神经电刺激（ES）是治疗面瘫后眼睑闭合功能障碍的一项有前景的技术。我们使用这种基于新型陀螺仪的方法来评估自发眨眼和电刺激诱发眨眼的生物力学，并确定最佳的电刺激方案。
眨眼过程中，眼睑围绕穿过眼角的轴线旋转，因此我们建议使用陀螺仪测量上眼睑的角速度（ωe）。通过对ωe信号进行积分来计算眼睑的角位移（θe）。从θe得出两个指标：1）闭眼时的眼睑角位移（C），计算为θe的峰值；2）眼睑闭合持续时间（D），计算为零信号与θe峰值之间的时间间隔。在一名健康志愿者身上，我们使用这种方法来量化自发眨眼以及不同电刺激模式诱发的眨眼。
对于自发眨眼，计算得出指标C = 14.0 ± 1.8°和D = 94.0 ± 10.8毫秒。通过比较自发眨眼和电刺激诱发眨眼的C和D指标，频率范围为200赫兹至400赫兹的10个脉冲序列被证明能诱发最有效且最自然的眨眼。
这种基于新型陀螺仪的方法被证明是一种有价值的工具，可提供眼睑运动的动态实时量化。它对于评估电刺激所提供的有效且自然的眨眼恢复可能特别有用。
