Better Hearing and Speech Month

Friday, May 20, 2022 Murray Tate

May is Better Hearing and Speech Month. This was established by the American Speech-Language-Hearing Association in 1927. Far too many of us ignore the things we could do to protect our hearing. I was one of them. Now I pay the price for that. Every minute of my life.

Our hearing comes about through a very complicated system. Damage to any part of it affects what we hear. Our hearing system is fragile enough that our hearing acuity tends to degrade somewhat as we age, even if we don’t suffer a damaging event to the hearing system. This is called presbycusis. It affects most all of us over time.

Our hearing system can be damaged by loud noises. This is called noise induced hearing loss (NIHL). We measure sound intensity in units called decibels (dB). Sounds above certain decibels for certain amounts of time can do damage. We measure sound pitch in frequencies (Hertz or Hz). Higher frequencies are perceived as higher pitch sounds. The higher the volume or loudness, the shorter the period of time we can be exposed to it without doing damage to our hearing. The higher the sound level, the shorter the amount of time it takes for damage to occur. With impact noises (the sound of one object hitting another such as the use of a hammer), damage can be done instantaneously.

Some sound levels produced by common things are shown below along with information as to what can happen from the exposure (from the CDC webpage concerning hearing loss).

Everyday Sounds and Noises	Average Sound Level in decibels	Typical Response (after routine or repeated exposure)
Softest sound that can be heard	0
Normal breathing	10
Ticking watch	20
Soft whisper	30	Sounds at these dB levels typically don’t cause any hearing damage.
Refrigerator hum	40
Normal conversation, air conditioner	60
Washing machine, dishwasher	70	You may feel annoyed by the noise
City traffic (inside the car)	80–85	You may feel very annoyed
Gas-powered lawnmowers and leaf blowers	80-85	Damage to hearing possible after 2 hours of exposure
Motorcycle	95	Damage to hearing possible after about 50 minutes of exposure
Approaching subway train, car horn at 16 feet (5 meters), and sporting events	100	Hearing loss possible after 15 minutes
The maximum volume level for personal listening devices; a very loud radio, stereo, or television; and loud entertainment venues	105–110	Hearing loss possible in less than 5 minutes
Shouting or barking in the ear	110	Hearing loss possible in less than 2 minutes
Standing beside or near sirens	120	Pain and ear injury
Firecrackers	140–150	Pain and ear injury

When our hearing system is damaged, the type of damage can vary. Usually, hearing loss is not constant across the span of frequencies that we can hear. Young people can usually hear from 20 to 20,000 Hz. Due to presbycusis (as mentioned in the second paragraph of this article) most of us in our sixties cannot hear frequencies above 12,000 Hz. But hearing damage can lead to frequency loss in much lower ranges.

Most the acoustic energy in normal speech is concentrated below 1000 Hz, especially in vowel sounds. However, most the information content is above 1000 Hz, where the consonants have their peak energies. Thus, people with NIHL … will often complain that they can hear speech but cannot understand it. This can lead to social isolation and depression.

Because of this, raising your voice when someone doesn’t understand what you say typically doesn’t help them understand any better. Those of us with hearing damage still misunderstand and get yelled at. When someone with hearing loss doesn’t understand you, it helps more if you rephrase what you are saying. Raising your voice rarely helps. Also, women and children tend to use higher frequencies than men do. Therefore, those with hearing damage can usually understand men more easily than women and children (I’m not sure my wife, daughter, and granddaughter believe this).

Background noise complicates understanding speech. Before my hearing aids, I frequently commented that everyone in a restaurant sounded like the parents in a Charlie Brown movie. It is hard for me to separate the background noise from the conversation in front of me.

High frequency hearing loss is also sometimes associated with tinnitus. Tinnitus is perception of a sound that does not exist. I hear a constant ringing in my ears. There are no quiet areas for me as I always hear this high-pitched whine. This further complicates my comprehension of spoken word since I also have NIHL.

In my personal case, I believe my NIHL was caused by frequent shooting of a .22 rimfire rifle in my younger days. I’m old enough that in those days, everyone told me I didn’t need ear protection for a .22 rifle. They were mistaken. A .22 rimfire still generates an impact noise. The impact noise of each shot I ever fired did damage that built up. I wear hearing aids now and have for a decade. They help a great deal but cannot overcome all of the damage done. Even with my hearing aids in, I sometimes have trouble understanding what you say to me. If you raise your voice and repeat the exact same words, I just misunderstand them again. I have trouble going to sleep at night because of the constant high-pitched whine I hear clearly in a quiet room.

With the advent of earphones and phones playing music, I see a whole generation that I expect will repeat my ear damage and have hearing trouble before age 40. Keep the volumes reasonable. For outside noises: earplugs are cheap, earmuffs are cheap. Please use them.

J. Murray Tate

Cranky old chemist