Insertion gain versus median ear corrected coupler gain: a comparison of two fitting methods in new NHS hearing aid users.

Although hearing aid fitting by insertion gain measurement is known to be an accurate and reliable technique, it is rarely used routinely in the UK National Health Service (NHS) because of high demands on staff and time. This study investigated whether an alternative, more practical procedure of fitting by median ear corrected coupler measurements would be as beneficial to NHS patients. Forty patients took part in a double-blind cross-over study comparing the two fitting methods. Results show that the insertion gain fittings were significantly better than the coupler fittings in terms of both patient preference and speech discrimination in noise. It is concluded that, even with the limited response adjustments available, individual deviations from the median ear make routine hearing aid fitting by insertion gain measurement indeed desirable in the NHS.