On the mechanism of the Menière attack.

Three theories are discussed dealing with the origin of the Menière attack: 1) The hypothesis of pressure induced changes is disproved. 2. The stimulation of the crista epithelium by a mechanical cupula deviation has been investigated. The results showed that the changes in action potential frequency of the ampullary nerve induced by maintained bending of the cupula, always declined and returned to resting potential frequency within a very short period of time usually within 1 min. Preventing the "elastic return" of the cupula did not change the time constant of this response decline. This proves that a Menière nystagmus lasting for hours, can not be elicited by a mechanical deformation of the cupula. 3) The paralyzing influence on vestibular nerve fibres by K+ ions in endolymph, leaking into perilymph spaces has earlier been demonstrated by the author. When the distended membranous labyrinth ruptures at predestined weak spots, leaking endolymph may reach and paralyze different nerve branches. This can explain all the main symptoms of a Menière attack.