1. Real Ear Testing Measures how a hearing aid performs in the ear Real Ear Unaided Response (REUR) Real Ear Aided Response (REAR) Real Ear Insertion Response (REIR) 1

2. Real Ear Unaided Response (REUR) Measures the natural amplification of the ear Determines how much amplification will be lost when the earmold is inserted into the ear This loss can be compensated in the fitting formula 2

3. Real Ear Aided Response (REAR) Measurement of the amplification produced by the hearing aid in the wearer’s ear. 3

4. Real Ear Insertion Response (REIR) Measurement of the actual gain the wearer will experience REIR = REAR - REUR 4