Progressive, age-related hearing loss is called presbycusis (from the Greek words presbys “elder” + akousis “hearing”).

Every person has a certain genetic disposition for presbycusis. If one of your parents became hard of hearing later in life, you may have an increased risk for hearing impairment as you age.

Various chronic diseases — including kidney and heart disease — can also degrade hearing.

Hearing loss is twice as common in people with diabetes than those without the condition. The reason for this connection may be due to the damage diabetes causes to the small blood vessels that supply the inner ear.

One of the most preventable causes of hearing loss is chronic exposure to loud noises. This was an issue for my patient Rob, who not only loved loud rock music but made his living selling stereo equipment, often by providing loud demonstrations.

But exposure to loud noises doesn’t need to be chronic to cause auditory damage. It can also result from a single intense-noise incident, such as an explosion. High-risk activities include: sport shooting, hunting, playing music loud, using headphones or earbuds, attending loud concerts and sports events.

Sound volume is measured in a unit called decibels. The 45-decibel sound from the humming of a refrigerator is just below a normal conversation, which averages 60 decibels. Noises louder than 85 decibels can cause hearing loss, including city traffic (85 decibels), an MP3 player at high volume (100 decibels), or a police siren (120 decibels).

The duration of exposure and distance from the sound will determine the risk for permanent hearing damage.

To perceive sound, ears must change sound waves into electrical signals that can be transmitted to the brain. These waves enter the outer ear and travel through the narrow ear canal to the eardrum, causing it to vibrate and transmit those vibrations through three tiny bones in the middle ear.

These bones transmit the vibrations through fluid in the inner ear, where tiny sensory hair cells bend from the waves and translate the signals into an electrical signal to the brain that we understand as sound.

Exposure to loud noise over time damages these tiny sensory hair cells, which will not grow back if they are damaged.

Meanwhile, a loud burst of noise from a gunshot or an explosion can damage the tiny bones in the middle ear or rupture an eardrum. Such loud noises can also cause ringing in the ears — a condition called tinnitus — which in some cases can become permanent.