“…In endolymphatic hydrops, a relative increase in endolymphatic fluid pressure causes hydromechanical changes within the scala media and subsequent displacement of the basilar membrane toward the scala tympani. SP elevation is known to reflect these changes Durrant and Gans, 1975;Ferraro et al, 1985). In addition, perilymph fistula is also thought to have the same mechanism as secondary endolymphatic hydrops, and exhibits endolymphatic hydrops histologically and increased SP/AP in animal models (Campbell and Savage, 1992) and in man (Arenberg et al, 1988).…”