Hj. Mcdermott et al., LOUDNESS PERCEPTION AND FREQUENCY DISCRIMINATION IN SUBJECTS WITH STEEPLY SLOPING HEARING-LOSS - POSSIBLE CORRELATES OF NEURAL PLASTICITY, The Journal of the Acoustical Society of America, 104(4), 1998, pp. 2314-2325
Loudness functions and frequency difference limens (DLFs) were measure
d in five subjects with steeply sloping high-frequency sensorineural h
earing loss. The stimuli were pulsed pure tones encompassing a range o
f frequencies. Loudness data were obtained using a 2AFC matching proce
dure with a 500-Hz reference presented at a number of levels. DLFs wer
e measured using a 3AFC procedure with intensities randomized within 6
dB around an equal-loudness level. Results showed significantly shall
ower loudness functions near the cutoff frequency of the loss than at
a lower frequency, where hearing thresholds were near normal. DLFs wer
e elevated, on average, relative to DLFs measured using the same proce
dure in five normally hearing subjects, but showed a local reduction n
ear the cutoff frequency in most subjects with high-frequency loss. Th
e loudness data are generally consistent with recent models that descr
ibe loudness perception in terms of peripheral excitation patterns tha
t are presumably restricted by a steeply sloping hearing loss. However
, the DLF data are interpreted with reference to animal experiments th
at have shown reorganization in the auditory cortex following the intr
oduction of restricted cochlear lesions. Such reorganization results i
n an increase in the spatial representation of lesion-edge frequencies
, and is comparable with the functional reorganization observed in ani
mals following frequency-discrimination training. It is suggested that
similar effects may occur in humans with steeply sloping high-frequen
cy hearing loss, and therefore, the local reduction in DLFs in our dat
a may reflect neural plasticity. (C) 1998 Acoustical Society of Americ
a. [S0001-4966(98)02910-5].