The binaural masking level difference as a function of frequency, masker level and masking bandwidth in normal-hearing and hearing-impaired listeners.

Binaural masking level differences (MLDs) were measured for 10 normal-hearing and 10 cochlear-impaired listeners, at 500 and 2 000 Hz. Maskers were either wide-band (approximately 2 000 Hz), or narrow-band (50 Hz). For wide-band maskers the noise pressure spectrum level was 50 dB/Hz, and for the narrow-band maskers the noise levels were 50 and 60 dB/Hz. At 500 Hz the hearing-impaired listeners show abnormally low MLDs in wide-band noise, but not in narrow-band noise. At 2 000 Hz, the hearing-impaired subjects show abnormally low MLDs only in narrow-band noise at the 50 dB/Hz level. The clinical implications of the results are considered.