PERCEIVED LATERAL POSITION OF NARROW-BAND NOISE IN HEARING-IMPAIRED AND NORMAL-HEARING LISTENERS UNDER CONDITIONS OF EQUAL SENSATION LEVEL AND SOUND-PRESSURE LEVEL

The perceived lateral position of narrow-band noise (NBN) was studied in a graphic pointer task as a function of the method of compensation for interaural threshold asymmetries in hearing-impaired and normal-he aring subjects. The method of compensation consisted of equal sensatio n level (EqSL) or equal sound-pressure level (EqSPL) at the two ears w ithin the same subject. The NBN signals were presented at 11 center fr equencies with interaural intensity differences (IIDs) that varied fro m -20 to +20 dB. When equalizing by SL, the perceived lateral position is essentially linearly dependent on the degree and direction of asym metry in asymmetric normal-hearing and hearing-impaired listeners. Equ alizing by SPL shows no such dependency but produces images that are l ateralized close to the midline. These results reveal that subjects ma y have adapted to their threshold asymmetries. These results will be d iscussed in terms of the fitting of binaural hearing aids. (C) 1997 Ac oustical Society of America.