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Age-related
hearing loss: gender differences.
Georgian Med News. 2007 Mar;(144):14-8.
Hearing
thresholds were measured in 224 Tbilisi citizens, 128 females and 96
males, at the frequencies of 0.125-16 kHz. None of the subjects
reported any job-related noise exposures or other potentially
confounding history. Initial signs of age-related hearing
impairments were detected in females and males of 40-49 and 30-39
years of age, respectively. In both genders they involved high
frequencies. In the following age decades, 50-59, 60-69, and 70-79
years, the hearing losses increased in magnitudes and extended to
lower frequencies. From the age of 30-39 years to that of 40-49 and
50-59 years the dynamics of threshold elevations appeared more rapid
in males than in females. The gender differences in hearing acuity
increased respectively in this age period. Thereafter, in the ages
of 60-69 and 70-79 years, the hearing alterations became steeper in
females than in males. As a result, the gender differences in
hearing smoothed significantly.
Presbycusis:
a human temporal bone study of individuals with downward sloping
audiometric patterns of hearing loss and review of the literature.
Laryngoscope. 2006 Sep;116(9 Pt 3 Suppl 112):1-12.
OBJECTIVE:
The purpose of this retrospective case review was to identify
patterns of cochlear element degeneration in individuals with
presbycusis exhibiting downward sloping audiometric patterns of
hearing loss and to correlate these findings with those reported in
the literature to clarify conflicting concepts regarding the
association between hearing loss and morphologic abnormalities.
METHODS: Archival human temporal bones from individuals with
presbycusis were selected on the basis of strict audiometric
criteria for downward-sloping audiometric thresholds. Twenty-one
temporal bones that met these criteria were identified and compared
with 10 temporal bones from individuals with normal hearing. The
stria vascularis volumes, spiral ganglion cell populations, inner
hair cells, and outer hair cells were quantitatively evaluated. The
relationship between the severity of hearing loss and the
degeneration of cochlear elements was analyzed using univariate
linear regression models. RESULTS: Outer hair cell loss and ganglion
cell loss was observed in all individuals with presbycusis. Inner
hair cell loss was observed in 18 of the 21 individuals with
presbycusis and stria vascularis loss was observed in 10 of the 21
individuals with presbycusis. The extent of degeneration of all four
of the cochlear elements evaluated was highly associated with the
severity of hearing loss based on audiometric thresholds at 8,000 Hz
and the pure-tone average at 500, 1,000, and 2,000 Hz. The extent of
ganglion cell degeneration was associated with the slope of the
audiogram. CONCLUSIONS: Individuals with downward-sloping
audiometric patterns of presbycusis exhibit degeneration of the
stria vascularis, spiral ganglion cells, inner hair cells, and outer
hair cells that is associated with the severity of hearing loss.
This association has not been previously reported in studies that
did not use quantitative methodologies for evaluating the cochlear
elements and strict audiometric criteria for selecting cases.
Presbycusic
neuritic degeneration within the osseous spiral lamina. Otol
Neurotol.2006 Apr;27(3):316-22.
OBJECTIVE:
To describe a neglected anatomic variant occurring with presbycusis.
STUDY DESIGN: Retrospective temporal bone histopathology study.
METHODS: Quantitative analysis of peripheral hair cells, neurites,
neurons, and the stria vascularis in temporal bones from individuals
who had presbycusis. Fifty-three patients aged 65 years or older and
with a down-sloping audiogram and clinical diagnosis of presbycusis
were reviewed. Nine cases had normal hair and ganglion cell
populations but reduced peripheral processes (neuritic presbycusis).
These were compared with five normal-hearing controls on
measurements of anterior middle and basal turn fiber bundle diameter
and the ratio of basal to middle diameters. RESULTS: Thresholds at 4
and 8 kHz were significantly poorer in the neuritic presbycusis
group than in the control group (p<or=0.004 and 0.05,
respectively), as was speech discrimination score (p<or=0.028).
The ratio of basal to middle turn diameters was significantly
smaller in the neuritic presbycusis group (p<or=0.003). This
effect was quite marked in that there was no overlap in ratios
between the groups, with the maximum neuritic presbycusis group
ratio smaller than the minimum control group ratio. There was a
moderate negative correlation between ratio and threshold at 4 kHz
(sigma=-0.49, p<or=0.075). CONCLUSION: Loss of peripheral
neurites in the anterior basal cochlear segment is found in
conjunction with presbycusis in temporal bones that have no other
morphologic abnormalities. These cases can be identified by a
gradual down-sloping audiogram in contrast to sensory (hair cell)
presbycusis, which is characterized by a precipitous high tone loss.
Histopathological
observations of presbycusis. Ann Otol Rhinol Laryngol. 1976
Mar-Apr;85(2 pt.1):169-84.
Temporal
bone histopathology of 17 aged patients who had spontaneous and
gradually progressive bilateral sensorineural hearing losses
associated with aging was studied. Six cases in the present material
showed the gradually sloping audiometric curve; nine cases, abrupt
high tone hearing loss; and two cases, the flat audiometric curve.
The most prominent histopathological change in the inner ear was a
decrease in the population of the spiral ganglion cells. However,
diffuse senile atrophy was also often seen in the organ of Corti and
the stria vascularis. A positive correlation between the degree of
artheriosclerosis and the degree of sensorineural degeneration in
the cochlea was not obtained in the present cases. Also, the
correlation was not found to be consistent between the type of the
audiometric curve and the localization of lesions in the sensory,
the neural or the vascular elements in the cochlea. Our observations
show that a certain type of audiometric curve does not necessarily
indicate a lesion in a specific cochlear element.
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