What is “Calibrate for Open” fit and how is this measurement performed?

The “calibrate for open fit” is used when fitting an open fit hearing aid. It prevents sound leaking from the ear and picked up by the reference microphone during aided measurements. It is performed after the Real-ear unaided gain (REUG) in real ear insertion gain measurements and it is performed as the first measurement in real ear aided response measurements. 

It consists of a single step. The hearing aid is placed its correct position on the ear and the hearing aid must be switched off or muted (with the help of hearing aid fitting software). Once in position the calibrate for open fit measurement can be run. 

After the calibration for open fit has been performed, the hearing aid gets switched on (unmuted) and immediately afterwards, the real-ear aided response (REAR) measurements can be performed without the patient moving between these actions.