Audiological aspects of idiopathic perilymphatic fistula.

Audiological findings in 40 patients with surgically confirmed idiopathic perilymphatic fistula were investigated. Most patients complained of roaring tinnitus, hearing impairment, ear fullness, and hyperacusis. However, a popping sound and a streaming water-like sound were noticed only in 8. Pure-tone sensitivity included every kind of hearing impairment, from sudden profound, to normal sensitivity. Development of hearing impairment was sudden, and deteriorated further, fluctuating in order of frequency. In the early stage of perilymphatic fistula patients had low-frequency hearing impairment and evidenced dominant-negative SP in the electrocochleogram. These findings suggest that a fistula of the inner ear window is not solely responsible for the wide variety of signs and symptoms, and that there must be simultaneous lesions in the membranous labyrinth.