Tinnitus, Ciba Foundation Symposium 85

This volume reviews recent research and current clinical concepts of tinnitus, which Fowler described as an itch or tickle of the basilar membrane. More questions are asked than answered, and opinions and speculations often differ widely. Interesting research includes spontaneous cochlear emissions measurable in the closed external auditory meatus at surprisingly high levels (16 to 20 dB) in both normal and defective ears. Many subjects are unaware of this sound. A mechanical cochlear tinnitus can also be elicited by clicks. Both consist of narrow bands of noise matchable with heats and maskable. Positive electric currents applied to the promontory or round window suppress tinnitus in 60% of subjects. Similar suppression, probably by the carrier wave (16,000 to 20,000 Hz), occurs when cochlear implants are stimulated. Direct action on cochlear nerve fibers is presumed. Attempts to relate these findings clinically are highly speculative and inconclusive. Tinnitus is associated with 80% of