Tuning curves and pitch matches in unilateral, low‐frequency hearing loss: A case study

Abstract

Psychoacoustical tuning curves and interaural‐pitch matches were measured in a listener with a moderately severe hearing loss of primarily cochlear origin below 2 kHz. The simultaneous‐masked tuning curves at 1 kHz in his impaired ear show that as the level of the probe increased from 4.5 to 13 dB SL, (1) the frequency location of the tuning‐curve tip decreased from approximately 2.85 to 2.20 kHz and (2) the lowest masker level increased from 49 to 83 dB SPL. The tuning curves for different probe levels appear to reflect tuning properties of different populations of nerve units. The tuning curve in his normal ear was comparable to data from other normal listeners. The interaural‐pitch matches were measured from 0.5 to 6 kHz at 10 dB SL in the impaired ear and approximately 15 to 20 dB SL in the normal ear. Results show reasonable identity matches (e.g., a test frequency in the impaired ear was matched relatively close to the same test frequency in the normal ear), although variability was significantly greater for pitch matches below 2 kHz. The pure‐tone pitch matches of this listener in the impaired frequency region appear more easily explained in terms of temporal theories than place theories of pitch perception. [Work supported by NIH.]