Age-related hearing loss is by far the most common type of hearing loss, affecting about one-third of those aged 60–69, and two-thirds of those aged 70 and up. While these numbers are striking, it can be useful to remember that no two hearing losses are exactly alike, and that one person’s hearing loss may be more easily treated than another’s.
Korean Study Finds More High-Frequency Hearing Loss
High-frequency hearing loss (defined as hearing loss in the 2,000–8,000 Hz range), as we might expect, turns out to be even more common than broad-spectrum hearing loss. A study conducted in Korea found that the rates of high-frequency hearing loss for study participants over age 60 were typically much higher than rates for mid-range frequencies (though these were also high).
For those aged 60–69, hearing loss was present at 3,000 Hz at a rate of 42.7%, and at 6,000 Hz at a rate of 79.5%. For those 70 and older, hearing loss was present at 3,000 Hz at a rate of 70.7%, and at 6,000 Hz at a rate of 93.2%. It seems that as we age, we are all nearly guaranteed to experience high-frequency hearing loss.
The spectrum of sound is divided into frequencies. Frequency measures the waves of particle vibration that carry sound. We measure frequency in “hertz” (Hz). One Hz means that the wave oscillates once per second, producing an extremely low-pitched tone that humans cannot hear. 50,000 Hz—or 50 kHz (kilohertz)—means that the wave oscillates 50,000 times per second, producing an extremely high-pitched tone that humans cannot hear.
The range of human hearing is usually given as 20 Hz – 20 kHz, though there are significant differences between individuals even from birth. Most people begin to lose the ability to hear the highest highs already by age 8.
Hearing Tests and Frequency Measurement
When you take a hearing test, the results of the test are displayed on an audiogram. The audiogram represents low-to-high frequencies from the left to the right, and an inverse decibel scale from top to bottom, indicating how loud a sound has to be at a particular frequency in order for you to hear it.
The frequencies that are measured during a typical pure-tone hearing test, and thus displayed on an audiogram, are as follows: 250 / 500 / 1k / 2k / 4k / 8kHz. Notice that the Hz doubles with each additional plot, from bottom to top. The doubling of any given frequency produces what in music we call an octave—the “same” tone, but higher or lower in pitch. Relationally, the lower or higher octave of any pitch has the same function in the harmony of music.
Many hearing care specialists also measure 3kHz and 6kHz. These are frequencies that are typically accentuated by the shape of our ear canals, which is thought to have been evolutionarily advantageous in that it allows us to hear human speech more easily. It also has the consequence that noise-induced hearing loss (NIHL) is typically more pronounced at these frequencies, since any sound our ears receive tends to be effectively louder here.
Some audiologists have even begun to measure still higher frequencies, into the 10,000 Hz+ range. While hearing loss here is relatively common even amongst younger people, it may be predictive of hearing loss at mid-range frequencies. Even significant hearing loss above 10,000 Hz would not mean that a person should wear hearing aids, but it might mean they should wear earplugs more often!
Why Is High-Frequency Hearing Loss a Problem?
Hearing loss in the 2 kHz – 8 kHz range makes it more difficult to understand the consonant sounds in speech. It makes it more difficult to hear the voices of children and women. Often, people with high-frequency hearing loss will say, “I can hear—I just can’t understand.” That’s because so much of speech is defined by the consonant sounds, which is exactly what goes unheard. You can tell someone is talking, you just can’t distinguish between the words they’re saying.
Depending on the severity of high-frequency hearing loss, hearing aids may be recommended following a hearing test. If hearing aids are recommended, it is important to start wearing them as soon as possible. Hearing loss that goes untreated for a significant length of time can result in what hearing care providers often call a “cascade of negative outcomes” for health and well-being, so don’t delay: