On the Pitch Strength of Bandpass Noise in Normal-Hearing and Hearing-Impaired Listeners

The psychoacoustic measure pitch strength describes the strength of the tonal sensation evoked by a sound on a scale from weak to strong. For normal-hearing listeners, it was shown in the literature that pitch strength of bandpass noise (relative to the pitch strength of a sinusoid at its center frequency) decreases with increasing bandwidth. This decrease also depends on the center frequency. These effects were often attributed to the frequency selectivity of the auditory system. The present study investigated the relative pitch strength of bandpass noise in hearing-impaired listeners and for comparison in a normal-hearing control group. For the normal-hearing listeners, pitch strength was measured at sound pressure levels of 30 and 70 dB SPL for bandwidths between 5 and 1620 Hz and center frequencies of 375, 750, and 1500 Hz. In addition, two ways of generating the stimuli (filtering in frequency or time domain) were used to compare the data with previous results. Apart from the known effect of center frequency on the change of relative pitch strength with increasing bandwidth, stimulus generation also had a significant influence on the results. Relative pitch strength of bandpass noise in hearing-impaired listeners was measured for bandwidths from 5 to 1620 Hz; the center frequency was 1500 Hz. Compared with the corresponding results of the normal hearing, relative pitch strength was altered in the hearing-impaired listeners. These alterations, however, could not be explained by altered spectral processing in the damaged cochlea alone.