Contribution
Acoustic evaluation of the operation and fitting range of hearing aids
* Presenting author
Abstract:
Hearing aids are available in different styles, at multiple technology levels, and with various fitting ranges. While style and technology level are usually chosen by the user as part of individual counselling, the required fitting range is determined by the existing hearing loss. However, there exists no common or standardized procedure for the determination of a fitting range. Therefore, we investigated several factors defining the operation and fitting range of hearing aids. First, a procedure is suggested to test the limit of the dynamic range at low levels due to internal noise and expansion which is currently not appropriately covered by the equivalent input noise (EIN) according to IEC 60118-0. Second, an approach is presented to test the limit of the dynamic range at high sound pressure levels independently at the input and output. Third, hearing aids with different power levels were coupled to a head and torso simulator (HATS) with different vents. It was then tried to best as possible meet the gain targets according to NAL-NL2 for various hearing losses. Considering all results, it is discussed whether it is feasible to define a standardized procedure for the determination of the fitting range based on acoustic measurements.