Partial masking and pitch shifts in impaired ears

Abstract

In a previous paper [Burns and Oesterle, J. Acoust. Soc. Am. Suppl. 1 67, S20 (1980)] we reported on an experiment in which the pitch shift, loudness reduction, and reduction in (nonsimultaneous) masking effectiveness of pure tones were measured as a function of the spectrum level of a broadband noise masker in normal hearing subjects. There was, in general, not a good correlation between the amount of pitch shift and the amount of loudness reduction or the amount of reduction in masking effectiveness. For example, significant differences in the magnitudes of pitch shifts in the two ears of a given subject were not reflected in the measurements of partial masking. The present paper reports on a similar experiment performed on observers with various configurations of sensorineural hearing losses. The results show more dramatically the lack of correlation between partial masking and pitch shifts. In a number of cases normal or exaggerated pitch shifts were found with little or no partial masking being evident. In other cases gross differences in the pitch shifts between the two ears were found whereas partial masking was virtually identical in the two ears.