Binaural interaction in hearing impaired listeners

Abstract

The binaural hearing abilities of four sensori-neural loss listeners were tested in four experiments: (1) interaural time discrimination, (2) interaural intensity discrimination, (3) interaural correlation discrimination, and (4) binaural detection experiments. All tests were conducted on each subject using third-octave bands of noise centered at 250, 500, 1000, 2000, and 4000 Hz. “Binaural Audiograms” can be obtained by plotting the ration of normal discrimination jnds to measured discrimination jnds versus frequency on a log-log scale. In general, the frequency dependence of binaural hearing loss, so defined, appears unrelated to the frequency dependence of hearing loss as measured by current monaural audiometric techniques. Furthermore, impairements of interaural time discrimination are independent of impairments in interaural intensity discrimination. Finally, the MLD alone was not related to loss of interaural time or intensity sensitivity. Two of the subjects tested showed elevated NoSπ and NoSo thresholds, poor interaural time and intensity discrimination but a “normal” MLD. [Work supported by NIH Grant NS10916.]