“…Whichever the trial design, various devices and measuring methods have been used to assess head movements [ 14 , 15 ], including ultrasound-based trackers [ 19 ], electromagnetic devices [ 20 ], electrogoniometers [ 21 ], digital goniometers [ 22 ], inertial measurement units [ 23 , 24 ], radiography [ 25 ], video-fluoroscopy [ 26 ], head-mounted laser pointer devices [ 16 , 27 ], virtual reality systems [ 28 ], and optoelectronic systems [ 29 ].…”