兔眼轮匝肌的肌电信号研究

Research on the electromyographic signals of orbicularis oculi muscle of rabbit

目的 分析健康家兔眼轮匝肌（orbicularis oculi muscle,OOM）不同运动模式下的肌电信号特征,明确肌肉功能与肌电之间的关系,以期获得OOM肌电控制信号的信息,为人工面神经假体恢复单侧周围性面神经麻痹患者的闭眼功能提供参考.方法 将微电极经上、下眼睑植入健康家兔的OOM内,采集OOM的肌电信号,并从时域、频域两方面分析信号特征.结果 自然持续睁眼、自然持续闭眼、自然眨眼、诱发闭眼模式下OOM肌电的峰振幅分别为（28.8±4.8）μV、（36.0±4.7）μV、（398.8±195.7）μV和（715.4±249.7）μV,4种模式下的肌电信号功率谱（power spectrum density,PSD）峰频率分别为（98±17）Hz、（142±22）Hz、（203±58）Hz和（349±81）Hz.肌电活动在自然睁眼及自然闭眼时较平稳、幅值较低;自然眨眼及诱发闭眼时,肌电幅值明显增强,且诱发闭眼时肌电振幅增强程度较自然眨眼时强烈.持续睁眼与持续闭眼时肌电峰值绝对值均小于50 μV;自发眨眼及诱发闭眼动作发生时的肌电起始幅值绝对值在50～60 μV之间.OOM肌电PSD能量分布的整体频带为0～500 Hz,主要集中频带为20～350 Hz.在时域内,持续睁眼与持续闭眼OOM的肌电信号峰值绝对值差异无统计学意义（P＞0.05）;其他各模式下峰值绝对值的两两比较差异均有统计学意义（P值均＜0.05）.在频域内,持续睁眼与持续闭眼OOM肌电信号PSD峰频率的差异无统计学意义（P＞0.05）;其他各模式下PSD峰频率间的两两比较差异均有统计学意义（P值均＜0.05）.结论 睁眼时OOM处于舒张状态,眼睑闭合动作是OOM收缩的结果.OOM肌电信号在不同运动模式下各具特点,可作为计算机判断识别此肌运动模式的依据,但根据时域和频域内OOM肌电特征很难将自然持续睁眼和自然持续闭眼状态进行区分.

Objective To study the features of electromyogaphic signals of orbicularis oculi muscle （OOM） of normal rabbits in various movement states, and to clarify relationships between functional actions of OOM and their electromyographic signals, hoping to obtain information concerning the electromyographic signals controlling OOM as reference for restoring the eye-closing function by artificial facial nerve prosthesis in patients with unilateral peripheral facial palsy. Methods The electromyographic signals were extracted from OOM of normal rabbits by implanted microelectrodes through upper and lower eyelids. Then the features of these electromyographic signals were analyzed in the time domain and the frequency domain. Results The peak values of the absolute electromyographic amplitude for natural continuous eye-opening event,natural continuous eye-closing state, natural eye-blinking movement and evoked eye-closing state were （28. 8 ± 4. 8） μV, （36. 0 ± 4. 7 ） μV, （ 398. 8 ± 195.7 ） μV, and （ 715.4 ± 249. 7 ） μV, respectively. The peak frequency values of the power spectrum density （PSD） of electromyographic signals for the four modes were（98 ± 17 ） Hz, （ 142 ±22） Hz, （203 ±58） Hz, and（ 349 ± 81 ） Hz, respectively. The electrical activities during the natural continuous eye-opening event and the natural continuous eye-closing state were stable and displayed low amplitudes. During the spontaneous blink state and the evoked eye-closing state, the electromyographic amplitudes markedly increased, and the increased level in the latter state was stronger than that in the former state. When rabbits continuously closed eyes or opened eyes, all of the peak values of thc absolute voltage amplitudes were less than 50 μV. The absolute amplitude values of the starting site were between 50 μV and 60 μV during the spontaneous blink and the evoked eye-closing movements. The whole frequency band of the energy of PSD about OOM was between 0 Hz and 500 Hz, and the focus frequency range was between 20 Hz and 350 Hz. In the time domain, the difference was not significant for the electromyographic signals of OOM between the continuous eye-opening state and the continuous eye-closing movement （ P 〉 0. 05 ）, but there were statistically significant differences in the other states for their pairwise comparisons（ P 〈0. 05）. In the frequency domain, there was no statistically significant difference for the peak frequency of PSD about the electromyographic signals when comparing the continuous eye-opening state with the continuous eye-closing event（ P 〉 0. 05 ）. When comparing this item in the other movements with each other, however, the differences were statistically significant （ P 〈 0. 05 ）. Conclusions OOM relaxes when eyelid keeps continuously opening. The action of eyelid-closing is due to contraction of this muscle.Each state has its own features of the electromyographic signals for OOM, these features can be used as criteria for computers to judge and identify various movement states of OOM. However, it is difficult to distinguish the natural continuous eye-opening event from the natural continuous eye-closing state, based on the features of electromyographic signals in the time and frequency domain.