Determining fitting ranges of various bone conduction hearing aids.

OBJECTIVES: To define fitting ranges for nine bone conduction devices (BCDs) over different frequencies based on the device's maximum power output (MPO) and to validate the assessment of MPO of BCDs in the ear canal.

BACKGROUND: Maximum power output (MPO) is an important characteristic when fitting BCDs. It is the highest output level a device can deliver and is one of the major determinants of a device's fitting range. A skull simulator can be used to verify MPO of percutaneous BCDs. No such simulator is available for active and passive transcutaneous devices.

DESIGN: The MPO of nine different BCDs was assessed either by real-ear measurements and/or with skull simulator measurements.

MAIN OUTCOME MEASURES: MPO and cross-validation of the methods using the Bland-Altman method.

RESULTS: Percutaneous BCDs have higher MPO levels compared to active and passive transcutaneous devices. This results in a wide dynamic range of hearing for percutaneous devices. Moreover, the assessment of MPO by real-ear measurements was validated.

CONCLUSION: Based on MPO data, fitting ranges were defined for nine BCDs over seven frequencies.