Presbycusis is defined as progressive sensorineural hearing
loss associated with aging.
This large cross-sectional study
demonstrates that the majority of sensorineural hearing
loss occurs in the elderly.
Longitudinal studies of hearing
loss accounting for age, sex, and noise exposure history
demonstrate that 97% of subjects experienced a decrease
in hearing over time.
Patients younger than 55 years
lost hearing at an average rate of 3 dB per decade, and
patients 55 years and older lost hearing at a rate of 9 dB
By correlating pure tone audiometry and temporal bone
histologic findings in patients with presbycusis, four types
of presbycusis can be defined:
sensory (hair cell loss)
neural (spiral ganglion cell loss)
metabolic or strial (loss of the stria
mechanical (change in the mechanical stiffness
of the cochlear duct with aging).