The practical application of ultrasound was initiated in France in 1916 with the study of underwater echo.1 Mulwert and Voss2,3 attempted to treat the hard of hearing with ultrasound from 1928 to 1933. Their apparatus produced waves of low intensity and afforded no convincing results. In 1948, Austrian investigators Wiethe, Wyt, and Vyslonzil4,5 reported the treatment of various ear diseases with ultrasound. The results of treatment varied considerably; they were usually doubtful, and treatment failed in several cases. A comparison of these results is difficult. Naumann6 concluded that the treatment of ear diseases with ultrasound was useless, as the total quantity of ultrasonic waves reaching the inner ear was insignificant. This was due to the fact that the air in the mastoid cells prevented the ultrasonic waves from reaching the inner ear. Only in patients with a sclerotic mastoid could a significant intensity of ultrasonic waves