Objective: This study includes a battery of psychoacoustical and electrophysiological tests to quantitatively investigate the changes in the frequency and the temporal features of the human auditory periphery caused by aging (presbyacusis) and noise-induced lesions, two common types of sensorineural hearing impairments. The scores are comparatively analyzed.
Design: These clinical experiments have been implemented in MATLAB software.
Study sample: 20 normal hearing adults (aged 30-54), 20 older hearing-impaired subjects (aged 65-70) with no history of Ototoxic medication or noise exposure and 7 adult men with a traceable noise-induced hearing impairment.
Results: The observed temporal and spectral declines are generally consistent with the high-frequency audiometric loss depicted by the audiogram, for each group. Moreover, the test battery provides valuable information on the frequency sensitivity, temporal resolution, loudness growth, compression and otoacoustic emissions.
Conclusion: These scores are compared with the predictions of a physiologicallybased cochlear model to provide evidence about specific inner-ear pathologies, beyond what the audiogram can indicate. Among these 7 clinical experiments, the results from the forward temporal masking test, the categorical loudness discrimination test and the distortion product otoacoustic emission test provide the most differential information about the underlying cellular lesions. The results indicate that the reduction in the temporal resolution is substantially age-relate since the presbyacusis listeners, unlike the other groups, obtained almost no benefit from the temporal cues provided by the gap duration at any of the experiments. Moreover, the results suggest that the DPOAEs reflect the cellular lesions associated with the acoustic overstimulation rather than the age-related strial degenerations.
Inner ear pathologies, Cochlear lesion, Sensorineural hearing impairment, Auditory models