[In-situ measurement as necessary component of hearing aid fitting].

The most important ear simulator measurement methods like 2-cm3 coupler, Zwislocki coupler, KEMAR were outlined. The disadvantages of these measurement methods were listed. So the ear simulator methods not take into account the individual anatomic conditions like the residual volume between the earmold and the eardrum, the impedance of the middle ear and the outer ear resonance. The influence on the sound pressure level in front of the eardrum caused by modifications of ear molds as another very important part of the hearing aid fitting, can not be assessed by measurement far away from the patients ear. All these individually varying factors only can be integrated into the hearing aid fitting by real ear measurement in front of the eardrum.