Eyelid and Blink Tracking in an Animal Model of Facial Palsy

Facial palsy (FP) is a clinical condition resulting from damage to the facial nerve. We hypothesize that activity can be restored in the injured side, by electrical stimulation of its muscle, using the activity of muscles on the healthy side as a control input. To explore this hypothesis, we are using a rat model of FP, which treats blinking and whisking as the features of interest in facial movement. This paper describes the development of a novel methodology for the automatic detection and measurement of eyelid displacement and blinks in video records of the rat. Specifically, the active contour approach was used to localize and track rodent eyes in a head-fixed video. The algorithm is initialized manually marking the eye contour in the first frame of the video; subsequent frames are analyzed automatically based on an energy function that depends on image features in the region of interest. Our results demonstrate that our novel technique detects blinks in video recordings with a success rate of 100% and a high correlation between the algorithm output and the manual validation.