Vestibular and oculomotor disturbances in pathology of the fourth ventricle.

Positional nystagmus of the central type and gaze paretic (gaze evoked) nystagmus have been reported in pathology of the posterior fossa. It has also been reported that positional nystagmus of the central type is only infrequently accompanied by vertigo and nausea. In this paper five cases are discussed which showed positional nystagmus of the central type and/or gaze paretic nystagmus. All cases showed severe vertigo, nausea and vomiting in the provocative head position. In four out of five cases the pathology was found to be in the area of the IVth ventricle. On the basis of recent neurophysiologic data an attempt is made to explain the manifestations of this pathology. It is concluded that positional nystagmus of the central type is presumably due to pathology of the IVth ventricle area. Also, that this type of nystagmus may be accompanied by severe vertigo, nausea and vomiting.