Named after Prosper Menière, who first described it in 1861, the disease is characterised by TINNITUS, deafness and intermittent attacks of VERTIGO. The first manifestation is usually deafness on one side; then – often, many months later – there is a sudden attack, without any warning, of intense vertigo. This acute giddiness usually lasts for two or three hours, with some unsteadiness persisting for a few days. The time interval between attacks varies from a week to a few months and, when they recur, they tend to do so in clusters. The tinnitus, which tends to be low-pitched, comes on at about the same time as the deafness; it is often described as being like rushing water or escaping steam. The deafness becomes gradually worse until it is complete. The condition is due to excessive fluid in the labyrinth of the ears (see EAR). The cause of this accumulation is not known, although it has been suggested that it might be a form of ALLERGY, or might be due to spasm of small blood vessels. The disorder is diagnosed by AUDIOMETRY, the CALORIC TEST and other investigations.