The author points out some considerations on the spontaneous nystagmus in Otoneurology, basing himself on 74 cases: 31 syndromes of the cerebellar pontine angle, 40 of the brain stem and 3 of the cerebellar hemispheres. The possibilities of otoneurological diagnosis, more important in the syndromes of cerebellar pontine angle than in the syndromes of the brain stem, are discussed.