Cervical vertigo.

It has been known for decades that movements of the neck can provoke eye movements. Barany 1 and Voss 2 demonstrated them in newborn children; de Kleyn, 3 in rabbits. A sustained torsion of the neck in these circumstances leads to a sustained compensatory eye deviation interrupted by nystagmus beats. In mature humans, turning of the neck causes eye movements only in a patient whose eyes are closed or who are examined in the dark. 4,5,6,7,8 Though the combination of compensatory eye movements and nystagmus is found again in this case, the sustained deviation of the eyeball during sustained deviated positions of the neck is not found. Not only neck torsion, but even torsion of the thorax or the pelvis in respect to the adjacent parts of the spine, suffices to elicit nystagmus, 4,5 and it must be kept in mind that the angles over which neck, thorax or pelvis must be rotated in order to provoke eye movements need not be extreme. Rotations of 90° or even less, in general, suffice.