A reexamination of the one-half gain rule.

ABSTRACT

A one-half gain rule for hearing aid fitting based on the unaided average hearing threshold level was first proposed by S. F. Lybarger. From records on almost 500 clients with sensorineural loss for whom hearing aids were prescribed and fitted, the functional gain for speech reception threshold, 500 Hz, and the average of 1000 and 2000 Hz was examined. The one-half gain rule was found to be valid for speech reception threshold except with mild hearing losses where the gain obtained was a little less than one-half the unaided hearing threshold level. The one-half gain rule is easily computed and provides a good first-order approximation of operating gain needs.