05 Jun Hearing With Our Brain, Not Our Ears
When we think of hearing we usually think of hearing through our ears. The ears, however, are just one small part of the hearing system. Problems with the brain, not just the ears, contribute to age-related hearing loss in older people. As we age, there are increasing problems with the way our brain processes auditory information. This breakdown in our ability to organize and understand what is heard explains why an older individual with normal hearing may still have a lot of trouble hearing and understanding speech.
Normally, the brain does an excellent job of filtering, sorting, and making sense of the information that comes to our senses – the colors and shapes we see, the various smells we smell, the textures of the objects we feel, and a range of sounds from the flutter of a hummingbirds wings to the shrill sound of a fire alarm. Our brain sorts all of this information in ways that make it easy for us to carry on our lives. Sometimes, it is this inability of the brain to sort sounds, and not hearing itself, that has declined in older people that have difficulty hearing.
The most common hearing complaint voiced by older people, is the inability to hear speech in background noise such as at a party or a restaurant. This difficulty may be partially due to an age-related high pitched hearing loss which makes it hard to hear the consonants in words. But, whether or not a high pitched hearing loss is present, the inability to hear speech in a noisy place is compromised by the aging brains ability to filter out unwanted and unnecessary background noises. Therefore, speech gets lost in the noise. Without an efficient working filter system, the brain is easily overcome with too much information that is difficult to sort and then becomes overwhelming. The brains filtering ability begins its decline as we move into our 40’s and 50’s.
Another component of age-related hearing loss is a reduction in our ability to detect small differences in pauses of sounds in speech. This difficulty in identifying when a sound is or is not present is known as a timing problem. The average person can hear sound gaps of about 2 milliseconds apart, but someone with a timing problem may be anywhere from 2 to 50 times worse in detecting sound gaps, which are crucial (though subconscious) for properly hearing speech. Conversation with a person who has a timing problem sounds like everything is spoken through a drain pipe. One sound leads into the next, blurring all the words together. The problem has the most effect on a listeners ability to hear the first consonant of a word – hat, cat, fat, rat, may all sound the same. Timing problems complicate age-related hearing loss especially if background noise and a hearing loss are present.
We know that as we get older, it becomes more difficult to hear and follow a conversation. There are strategies that can be used to increase our success in hearing what is spoken. Recent research at the University of Maryland confirmed, for the first time, that seeing the person who is talking helps the brain process words faster and more accurately than if the words are only heard. Being able to see the person who is speaking will speed up the brains ability to process speech, as the movements of the mouth are then able to be seen before a sound is heard. The brain uses this slightly preceding visual information to make a prediction, almost instantaneously, of what that sound will be.
The combination of seeing and hearing speech allows for faster and more accurate speech recognition than is possible by hearing alone. This study supports the need for older individuals to look at the person who is speaking and to read their lips.
The following communication strategies may be used by hard of hearing people to improve their ability to hear speech, especially in the presence of background noise:
- Ask people to slow down their rate of speech. The aging brain needs more time to understand what has been said.
- Get as close to the sound source as possible. The closer you are to the person who is talking, the better you will hear.
- Tell others that you are hearing impaired.
- Ask for repetitions. If you are unable to hear then have it written down.
- Pay attention. You need to know what is going on, in order to help follow conversations.
- Don’t interrupt. When we follow conversation for awhile, we are more likely to grasp the meaning than if we interrupt mid-way through.
- Wear two hearing aids if two have been recommended.
- Consider newer digital hearing aid technology which greatly reduces background noise and enhances speech.
As we age, our brain goes through many changes as does our body. The problems with the aging brain, which we all experience, are in addition to any hearing problems, which one may or may not have as one ages. Many people, even if they can still hear sounds as they get older, can have difficulty filtering and understanding speech because of the aging brain. Recognizing this, and knowing the types of coping strategies which are available, will help deal with at least some of the stress from hearing loss that can occur as we age.