LATERALIZATION AND FREQUENCY-SELECTIVITY IN NORMAL AND IMPAIRED HEARING

The onset-time difference DELTA T required to lateralize a 30-ms bifrequency tone burst toward the leading ear was measured as a function of the frequency difference DELTA F between the tone in the left ear and the tone in the right ear. At center frequencies of 0. 5 and 4 kHz, four normal listeners tested at 80 and 100 db SPL had DELTA Ts that were relatively constant at subcritical DELTA Fs, but increased at DELTA Fs wider than a critical band. At 1 kHz, DELTA T increased with DELTA F even at subcritical DELTA Fs. Ten listeners with cochlear impairments were tested at 100 db SPL. Seven had normal DELTA Ts at 4 kHz, despite hearing losses between 50 and 70 db.