Age-related hearing loss (Presbycusis)

Abstract

Presbycusis, or age-related hearing loss, is a common form of hearing loss in the adult, defined by the World Health Organization’s criteria as a speech frequency pure tone average (0.5, 1, 2 and 4 kHz) of greater than 25 dB in both ears. In a cohort study in the United States, the prevalence of hearing loss (defined by audiometry) increased steadily with aging: 11 % in the age group of 44 to 54; 25 % in the age group of 55 to 64; and 43 % in age group of 65 to 84. Temporal bone histology provides some insight into the underlying pathophysiology of presbycusis. In the histopathology classification system, presbycusis is subdivided according to the associated audiometric patterns of hearing loss i.e., abnormalities of inner ear vasculature, hair cells, and membranes. All these factors contribute to audiometric findings. The four main types of presbycusis include, namely:

1. sensory presbycusis;

2. neural presbycusis;

3. strial presbycusis (metabolic presbycusis); and

4. cochlear conductive or mechanical presbycusis. Recent epidemiologic studies on age-related hearing loss have suggested four primary categories of risk factors for presbycusis: cochlear aging, noise exposure, genetic predisposition, and health comorbidities. Most patients with significant age-related hearing loss benefit from the
use of hearing aids.