The relative accuracy of coupler and behavioural estimates of the real ear gain of a hearing aid.

Selection of a hearing aid frequency response is often initially based on coupler-measured performance, but is subsequently confirmed by functional measurement of real ear gain. It is usually assumed that functional gain measurement is necessary as confirmation because coupler measures do not take individual differences into account. This paper first argues from a theoretical standpoint that, if appropriate coupler/real ear correction factors are used, coupler estimates of real ear gain can be of comparable accuracy to functional estimates. It then uses experimental evidence from a study carried out by the author to show that, because of the variability in functional measurements of gain, suitably corrected coupler estimates of real ear gain can be more accurate than their functional counterparts.