Hearing aids are only one part of the equation when it comes to a proper hearing aid fitting.
There is also verification of a proper fitting, validation of benefit, and appropriate counseling for use of the hearing device. Real-ear measures are an important part of a hearing aid fitting as it is the only way to make sure the hearing aid is fit appropriately, although it is oftentimes not completed at hearing aid fittings or follow-up appointments.
Ear canals come in all different shapes and sizes, and these differences change the acoustics of the hearing aid on different individuals. Hearing aid manufacturers create an algorithm to estimate the appropriate amount of amplification for a hearing aid, but that hearing aid will sound different in different ears.
Real-ear measure testing involves placing a probe tube in an ear canal and measuring the output of the hearing aid in that ear. The amplification is then adjusted to ensure audibility and oftentimes to match prescriptive targets for a given hearing loss. Without this step, the fitting of a hearing aid is just a guess at where it should be set.
So, when you are in the market for a hearing aid, be sure to ask your hearing care provider if they use real-ear measures.