Speech discrimination ability and its relation to psychophysical tuning curves (PTCs)

PTCs were obtained from normal and hearing‐impaired listeners using a simultaneous masking paradigm. All impaired listeners presented fiat moderate sensorineural hearing losses with excellent (90%) speech discrimination ability (NU‐6) in quiet. Probe stimuli were presented at 10 dB SL for impaired listeners and were varied from 10–60 dB SL for normal subjects. PTCs were quantified in terms of Q10 and tip‐to‐tail intersect. Performance‐intensity functions for monosyllabic words were obtained as a function of signal‐to‐noise ratio for broadband and low‐pass (500 Hz) filtered noise. Normal listeners demonstrated a decrease in tip‐to‐tail intersect and an increase in Q10 with increasing probe level. Regardless of whether comparisons were made across constant SL or constant SPL, impaired listeners exhibited smaller tip‐to‐tail differences than normal subjects with less obvious changes noted in Q10. While speech discrimination performances in broadband noise was similar for both groups, performance in low‐pass ...