It is a fact that with the passage of time most people’s hearing deteriorates. The reason for this is that there is a gradual loss of the outer and inner capillary cells of the perilymph (eardrum / inner ear). This loss is more pronounced at the base of the cochlea, which detects the high frequencies that are important for good hearing when there is background noise and less severe in the middle sections that detect the main bulk of sounds from the surrounding space, and speech.
These alterations in the cochlea seem to begin at birth and thus there is a gradual loss of capillary cells in all people, although the rate of loss varies from person to person. The result of this progressive loss is usually not perceptible until the person reaches the age of 40.
It usually starts to prove difficult to perceive sound in conversations in a noisy environment (for example, inside a restaurant), because the loss of high frequencies makes it difficult to distinguish between different voices.
