REAL EAR MEASUREMENTS
Real-ear measurements are performed during the hearing aid fitting process to verify the performance of the hearing aid in an individual patient's ear. We place a soft, thin probe-tube into your ear canal and complete different measurements of sound to test how the sound is handled in the ear. This can be done with an open ear canal (no hearing aid in), with the hearing aid in place and not turned on and with the hearing aid in place and turned on. In doing so, we can verify the hearing aid is working properly in your ear, based on your hearing loss and your ear anatomy. This measurement is especially important in surgically altered ear canals and children's ear canals as the actual amount of volume or gain in the ear canal may differ significantly than the prescribed amount.
Digital hearing aids are designed to amplify all sounds differently, based on the input level (or volume) the hearing aid microphones pick up. Gain is the amount of amplification applied to the input, based on your hearing loss, which is then sent to the hearing aid speaker and into the ear canal as the output.
Output – Input = Gain or Input + Gain = Output
Real ear measurements and patients subjective input verifies soft sounds are soft, but audible, average sounds are comfortable and loud sounds are loud yet still comfortable. Performing real ear measurements determine the hearing aid is working as it should in your ear. Other hearing aid features, such as noise reduction capabilities can also be measured.
The graph is an example of real ear “speech mapping” measurements. The dotted lines on the graph are target levels for the hearing aid to achieve at different input levels, while the solid lines display what the hearing aid performs. This graph tells us the hearing aid is performing well in this patient’s ear.
Purple = Soft Speech (50 dB)
Orange = Average Speech (60 dB)
Blue = Loud Speech (80 dB)
Green = Maximum Power Output; to verify the hearing aid never exceeds your comfort level
Open circle = Patient's hearing loss