Spontaneous vertical eye movements in coma.

Patients in coma may exhibit several different types of spontaneous ocular movements. Three forms of spontaneous vertical movements have been distinguished based on the relative velocities of their downward and upward phases. The pathophysiological basis of all these movements has remained obscure. Two patients are reported who demonstrated all three types of spontaneous vertical movements (ocular bobbing, ocular dipping, and reverse ocular bobbing), implying that the movements may all be differing manifestations of the still unknown pathophysiological process.