Relations between auditory functions in impaired hearing.

Relations between auditory functions, as expressed by coefficients of correlation, were studied for a group of 22 sensorineurally hearing-impaired subjects with moderate losses. In addition to the audiogram, we measured frequency resolution, temporal resolution, and speech reception in quiet and in noise. Frequency resolution was derived from masking with comb-filtered noise and from the psychophysical tuning curve, for both paradigms in simultaneous and in nonsimultaneous masking. The critical ratio was also determined. Temporal resolution was determined with intensity-modulated noise and from backward and forward masking. All tests were performed at 1000 Hz. Correlations among tests were gathered in a matrix and subjected to a principal-components analysis. It turned out that tests on frequency resolution form a cluster, and are approximately independent of audiometric loss. Furthermore, hearing loss for speech in noise is closely allied to frequency resolution, whereas hearing loss for speech in quiet is governed by audiometric loss.