Frigerio Alice, Hadlock Tessa A, Murray Elizabeth H, Heaton James T
Human Physiology Section, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Milan, Italy; Facial Nerve Center, Carolyn and Peter Lynch Center for Laser and Reconstructive Surgery, Division of Facial Plastic and Reconstructive Surgery, Department of Otology and Laryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston.
Facial Nerve Center, Carolyn and Peter Lynch Center for Laser and Reconstructive Surgery, Division of Facial Plastic and Reconstructive Surgery, Department of Otology and Laryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston.
JAMA Facial Plast Surg. 2014 May-Jun;16(3):211-8. doi: 10.1001/jamafacial.2014.1.
IMPORTANCE Facial paralysis remains one of the most challenging conditions to effectively manage, often causing life-altering deficits in both function and appearance. Facial rehabilitation via pacing and robotic technology has great yet unmet potential. A critical first step toward reanimating symmetrical facial movement in cases of unilateral paralysis is the detection of healthy movement to use as a trigger for stimulated movement. OBJECTIVE To test a blink detection system that can be attached to standard eyeglasses and used as part of a closed-loop facial pacing system. DESIGN, SETTING, AND PARTICIPANTS Standard safety glasses were equipped with an infrared (IR) emitter-detector unit, oriented horizontally across the palpebral fissure, creating a monitored IR beam that became interrupted when the eyelids closed, and were tested in 24 healthy volunteers from a tertiary care facial nerve center community. MAIN OUTCOMES AND MEASURES Video-quantified blinking was compared with both IR sensor signal magnitude and rate of change in healthy participants with their gaze in repose, while they shifted their gaze from central to far-peripheral positions, and during the production of particular facial expressions. RESULTS Blink detection based on signal magnitude achieved 100% sensitivity in forward gaze but generated false detections on downward gaze. Calculations of peak rate of signal change (first derivative) typically distinguished blinks from gaze-related eyelid movements. During forward gaze, 87% of detected blink events were true positives, 11% were false positives, and 2% were false negatives. Of the 11% false positives, 6% were associated with partial eyelid closures. During gaze changes, false blink detection occurred 6% of the time during lateral eye movements, 10% of the time during upward movements, 47% of the time during downward movements, and 6% of the time for movements from an upward or downward gaze back to the primary gaze. Facial expressions disrupted sensor output if they caused substantial squinting or shifted the glasses. CONCLUSIONS AND RELEVANCE Our blink detection system provides a reliable, noninvasive indication of eyelid closure using an invisible light beam passing in front of the eye. Future versions will aim to mitigate detection errors by using multiple IR emitter-detector units mounted on glasses, and alternative frame designs may reduce shifting of the sensors relative to the eye during facial movements.
重要性 面瘫仍然是最难有效治疗的病症之一，常常在功能和外观上造成改变人生的缺陷。通过起搏和机器人技术进行面部康复具有巨大但尚未实现的潜力。在单侧面瘫病例中，恢复对称面部运动的关键第一步是检测健康运动，以此作为刺激运动的触发信号。目的 测试一种可附着在标准眼镜上并用作闭环面部起搏系统一部分的眨眼检测系统。设计、地点和参与者 标准安全眼镜配备了一个红外（IR）发射器 - 探测器单元，水平穿过睑裂，形成一个监测红外光束，当眼睑闭合时该光束会中断，并在一个三级护理面神经中心社区的24名健康志愿者中进行测试。主要结果和测量指标 将视频量化的眨眼与健康参与者在静息注视时、从中心注视转移到远周边注视时以及产生特定面部表情时的红外传感器信号强度和变化率进行比较。结果 基于信号强度的眨眼检测在向前注视时灵敏度达到100%，但在向下注视时会产生误检测。信号变化峰值率（一阶导数）的计算通常能将眨眼与与注视相关的眼睑运动区分开来。在向前注视时，检测到的眨眼事件中87%为真阳性，11%为假阳性，2%为假阴性。在11%的假阳性中，6%与部分眼睑闭合有关。在注视变化期间，侧向眼球运动时假眨眼检测发生的时间为6%，向上运动时为10%，向下运动时为47%，从向上或向下注视回到主要注视时为6%。如果面部表情导致大量眯眼或使眼镜移位，会干扰传感器输出。结论和相关性 我们的眨眼检测系统使用在眼睛前方穿过的不可见光束提供了可靠的、非侵入性的眼睑闭合指示。未来版本旨在通过在眼镜上安装多个红外发射器 - 探测器单元来减轻检测误差，并且替代框架设计可能会减少面部运动期间传感器相对于眼睛的移位。
