Abstract
In order to decide indication for the use of hearing aid in deaf persons, the author studied improvement of hearing by hearing aids in the persons with normal hearing and deafness.Pure tone threshold, speech reception threshold and discrimination ability were used, and studied the following subjects:
(1) Functions of the hearing aids in a sound proof room.
(2) Effect of white noise on the function of the hearing aids.
(3) The indication for the use of the hearing aid evaluated by means of the pure tone audiornetry.
