Age-related hearing loss typically involves which anatomical structure?

• A. Ear canal
• B. Eardrum
• C. Middle ear bones
• D. Cochlea

Answer: (D)

Presbycusis, age-related hearing loss, is a sensorineural problem rooted in the inner ear. The cochlea is where sound gets turned into neural signals, and aging leads to degeneration of the sensory hair cells—especially the outer hair cells that amplify sound—reducing the clarity and strength of the signal. Neurons in the spiral ganglion can also decline, and changes in the stria vascularis can lower the endocochlear potential, further impairing transduction. Because these aging changes occur in the cochlea, the loss is typically bilateral and affects higher frequencies first.

The other parts—the ear canal, the tympanic membrane, and the middle ear bones—are involved in conductive pathways. Issues there cause conductive hearing loss, not the sensorineural pattern seen with presbycusis. So the cochlea is the anatomical structure most involved in age-related hearing loss.