The symptoms of Ménière’s disease are associated with a change in fluid volume within a portion of the inner ear known as the labyrinth. The labyrinth has two parts: the bony labyrinth and the membranous labyrinth. The membranous labyrinth, which is encased by bone, is necessary for hearing and balance and is filled with a fluid called endolymph. When your head moves, endolymph moves, causing nerve receptors in the membranous labyrinth to send signals to the brain about the body’s motion. An increase in the endolymph, however, can cause the membranous labyrinth to balloon or dilate, a condition known as endolymphatic hydrops.
Many experts on Ménière’s disease think that a rupture of the membranous labyrinth allows the endolymph to mix with perilymph, another inner ear fluid that occupies the space between the membranous labyrinth and the bony inner ear. This mixing, scientists believe, can cause the symptoms of Ménière’s disease. Scientists are investigating several possible causes of the disease, including environmental factors, such as noise pollution and viral infections, as well as biological factors.