|Judy R. Dubno, Richard A. Schmiedt, Mark A. Eckert, Fu-Shing Lee, Lois J. Matthews|
Introduction. Hearing loss due to aging (presbyacusis) is
a difficult problem to study because of the large number of
factors that may cause hearing loss in elderly people, such as
exposure to noise, ototoxic drugs, or some diseases.
Aim. To determine the extent to which anatomic and physiologic
changes observed in animal models with controlled pathologies
can be used to predict underlying mechanisms of age-related
hearing loss in older humans.
Material and methods. To determine if consistent patterns
of “audiometric phenotypes” can be identified from pure-tone
audiograms of older adults, schematic boundaries of audiograms
were defined based on four hypothesized conditions of
cochlear pathology obtained from results from animal models.
Audiograms of subjects (age >50) from the longitudinal study
of age-related hearing loss at the Medical University of South
Carolina (US) were searched by a human expert for “exemplars”
(best examples) of these phenotypes, without knowledge of
demographic information (N=1,728).
Results. Four audiometric phenotypes were defined: (1) older
normal, with generally normal hearing and a “pre-metabolic”
characteristic in the higher frequencies; (2) metabolic
presbyacusis, with a flat loss of ~20 dB in the lower frequencies
and a gradually sloping loss in the higher frequencies; (3)
sensory presbyacusis, with generally normal hearing in the
lower frequencies and a steeply sloping loss in the higher
frequencies; and (4) a mixed phenotype of metabolic + sensory
presbyacusis, with characteristics of metabolic presbyacusis in
the lower frequencies and sensory presbyacusis in the higher
Conclusions. Preliminary results to date suggest that animal
models can be used to predict human cochlear pathology
using audiograms and more advanced measures of auditory
function. Human audiometric phenotypes appear consistent
with predictions from animal findings associated with sensory
and strial pathology.
keywords: głuchota starcza, audiogramy, metaboliczny typ presbyacusis, czuciowy typ presbyacusis, presbyacusis, audiograms, metabolic presbyacusis, sensory presbyacusis
pages: from 74 to 80
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