Fig. 18.

Characteristics of head movements in healthy people. A: horizontal head movements of a healthy subject, who was instructed to point a head-fixed laser to light-emitting diode (LED) targets. The subject holds the head steady following each movement. B: similar movements but without the head-fixed laser. Without the visual cue regarding head position, the head drifts following completion of the movement toward a null position. C: the decay becomes faster when neck muscles are vibrated. From Shaikh et al. (2013), with permission.