M. Florentine et al., INTENSITY PERCEPTION .14. INTENSITY DISCRIMINATION IN LISTENERS WITH SENSORINEURAL HEARING-LOSS, The Journal of the Acoustical Society of America, 94(5), 1993, pp. 2575-2586
Intensity discrimination of pulsed tones (also called level discrimina
tion) was measured as a function of level in 13 listeners with sensori
neural hearing impairment of primarily cochlear origin, one listener w
ith a vestibular schwannoma, and six listeners with normal hearing. Me
asurements were also made in normal ears presented with masking noise
spectrally shaped to produce audiograms similar to those of the cochle
arly impaired listeners. For unilateral impairments, tests were made a
t the same frequency in the normal and impaired ears. For bilateral-sl
oping impairments, tests were made at different frequencies in the sam
e ear. The normal listeners showed results similar to other data in th
e literature. The listener with a vestibular schwannoma showed greatly
reduced intensity resolution, except at a few levels. For listeners w
ith recruiting sensorineural impairments, the results are discussed ac
cording to the configuration of the impairment and are compared across
configurations at equal SPL, equal SL, and equal loudness-level. List
eners with increasing hearing losses at frequencies above the test fre
quency generally showed impaired resolution, especially at high levels
, and less deviation from Weber's law than normal listeners. Listeners
with decreasing hearing loss at frequencies above the test frequency
showed nearly normal intensity-resolution functions. Whereas these tre
nds are generally present, there are also large differences among indi
viduals. Results obtained from normal listeners who were tested in the
presence of masking noise indicate that elevated thresholds and reduc
ed dynamic range account for some, but not all, of the effects of recr
uiting sensorineural impairment on intensity resolution.