Inter-Saccadic Interval Analysis of Vestibular Nystagmus

The time intervals between the onset of consecutive fast components, during vestibular nystagmus have been analysed by digital computer. The interval histogram shape varied with intensity of nystagmus in a manner similar to the reported observations in optokinetic nystagmus. As the intensity of nystagmus decreased, the interval histogram changed from being symmetric mono-modal, to asymmetric mono-modal, and finally to a multi-modal form in which the higher order modes were approximately integral multiples of the basic mode. The findings lead to new hypotheses concerning the neural networks generating vestibular and optokinetic nystagmus.