Table 2.

Laryngeal motion metrics and operational definitions.

Laryngeal motion metrics	Operational definitions	Units
Mean motion range ratio (MMRR)	Ratio of the right and left VF motion range (i.e., amplitude) during each respiratory cycle throughout a 10 s video clip, then averaged.	n/a
Open close cycle ratio (OCCR)	Ratio of the number of right and left VF motion cycles (i.e., frequency) throughout a 10 s video clip, then averaged.	n/a
Motion correlation coefficient (Mcorr)	Comparison of left and right VF motion direction (i.e., motion correlation coefficient) in each video frame throughout a 10 s clip, then averaged. Values range from −1 to 1, where values close to −1 represent a negative correlation (i.e., VF motion in opposite directions; normal function), values close to 1 represent a positive correlation (i.e., VF motion in the same direction; paradoxical motion), and values close to 0 represent minimal correlation (i.e., little to no VF motion).	n/a
VF angle	Measurement of VF maximum and minimum angle for each respiratory cycle throughout a 10 s video clip, then averaged.	degrees
Respiratory rate	Number of VF motion cycles per minute throughout a 10 s video clip, then averaged. VF abduction = inspiration; VF adduction = expiration.	#/min

For each mouse, one 10 s video clip of spontaneous breathing under anesthesia was analyzed via VFtrack™.