[Nystagmus as a diagnostic criterium in neurology]

The most frequent seen nystagmus is jerk nustagmus. It is a versional eye movement comprising a quick and a slow phase. For diagnostic reasons it is very important to know the connections involved in vestibulo-oculomotor control. Besides peripheral, labyrinthine disturbances the observation of nystagmus is a very good tool in the topodiagnosis of the brain stem and mesencephalon. By ENG recordings, which normally should be used only after clinical examinations according to Frenzel and Jung, we can find much more better and reliable results in clinical topodiagnosis. Further tests of vestibulo-oculomotor function (rotation, optokinetic tests e.g.) offer the possibility of a discriminating topodiagnosis of the brain stem. This means an efficient use in clinical neurology. Following these considerations examples of single cases including ENG recordings are given.