When you hear that hearing is normal, do you ever wonder what normal is? Is there a number associated with normal hearing or hearing loss for that matter? There is such a measurement. Acusis is the medical term for normal hearing. The threshold for normal hearing is an ability to hear frequencies between 0 and 25 decibels. Zero is average human hearing; it is the equivalent of 20/20 vision when a tone is audible at 0 decibels at every sound frequency.
When discussing what normal hearing is, it is essential to understand the concept of audiometric zero. Audiometric zero is the level of a pure tone of any given frequency that is minimally detectable by an individual with normal hearing. Researchers at the 1933 World’s Fair tested thousands of people to establish the level by taking an average of the lowest level that the people could hear at a frequency. This level is now what we consider to be normal hearing and from this, a standardized formula exists to determine hearing loss.
The results of a hearing evaluation appear on a graph called an audiogram. Loudness is measured from top to bottom on the chart. Frequency, from low to high is right to left on the graph. Hearing loss registers in decibels (dB). Professionals use the general list that follows:
An individual with a strong hearing ability can hear sounds ranging from 0 to 140 dB. A whisper averages around 25 to 30 dB. A conversation is 45 to 60 dB, and a rock concert is 110 dB. A young person should have hearing close to 20 dB, and it should remain acute throughout adolescence and early adulthood. Young adults tend to experience hearing damage from music players and car stereos. However, the range should stay the same. As a person ages, the probability increases that they will experience an age-related hearing loss. Sound frequency is another measurement for hearing.
A person can describe a sound in terms of frequency which is known as pitch. One can also measure it in intensity which is known as loudness with its measurement in hertz (Hz). A person with a normal hearing range can hear sounds with frequencies between 20 and 20,000 Hz. Speech includes a mix of low and high-frequency sounds. For instance, vowel sounds like short o have low frequencies and are usually easier to hear. Consonants such as s, h, and f have higher frequencies which make them harder to hear. Consonants convey the meaning of what we are trying to say, an inability to hear them can significantly impact hearing.
Now that you know just what normal hearing is, take the time to consider your ability to hear. A hearing evaluation administered by a hearing healthcare professional will help you know just where you are on the scales. So, take good care of your hearing today!