Many of us become concerned about hearing loss as we age, but we may also be concerned about our cognition, especially our memory. To have a conversation, we need our ears to hear, but also our brain to understand, keep track of, and remember what is being heard. Some changes in our ability to hear and remember are part of normal aging and some are not. Notably, hearing loss may affect our social interactions and even place us at risk for other health problems, like dementia or falls.
In this four part series, we examine the evidence for:
- how changes in hearing and cognition (for example, memory) affect communication and social interactions in healthy older adults (Part 1);
- how hearing impairment may be related to cognitive impairment and dementia (Part 2);
- what hearing tests can and cannot tell you about your hearing problems (Part 3); and
- when you should get your hearing assessed and what solutions might help you if you or your friends or family are having problems (Part 4).
In this first part, we look at auditory and cognitive changes in older adults who do not yet have clinically significant losses in either hearing or cognition (such as memory). How can changes in the ears and brain affect everyday communication and social interaction?
We need our ears for hearing, but to follow conversation we need our brain too.
As people get older, there are changes in the ear and changes in the brain networks that connect the ear to various parts of the brain. Recently, researchers have been trying to learn more about how the ear and brain work together and they have discovered some intriguing connections. Most people think that problems understanding speech in everyday conversations are only about our ears, but it turns out that our brain is involved as well. We need our brains to interpret the meaning of the sounds our ears are detecting. The continual mental or cognitive effort needed to listen can be stressful and reduce enjoyment of family gatherings and other social events. We need to understand more about how auditory and cognitive abilities change with age. Understanding these changes will give us insights into why so many older people complain of difficulties when they try to follow conversation, especially in noisy or busy group situations.
Think about what it is like to listen to a conversation at a party. Problems hearing in noisy situations can make it difficult to understand, pay attention to and remember what others are saying during conversation in social situations like parties.
Understanding what a sound means:
Sometimes you can hear a sound without recognizing or understanding it, especially if you were not expecting it. For example, you might hear a strange rattling sound in your house. It takes you a while to figure out that it is coming from a broken shutter flapping in the wind. Or you might hear a person talking in a foreign language without understanding the meaning of the words. As you listen, you use your brain to make sense of the sounds you are hearing with your ears. Your understanding of what you have just heard and your expectations in the situation help you to understand what you will hear next. You also use your brain to decide how to react to the sounds you are hearing. You might hear a fire alarm using your ears. But you need to use your brain to decide that there is danger and to plan your escape route.
Focusing attention on sounds:
People hear sounds whether they want to hear them or not. “Noise” refers to sounds that you don’t want to hear. For example, when you go out for dinner with your friend, you might find that it is interesting to eavesdrop on the person sitting next to you in the restaurant. The voice of the person sitting next to you is not noise. However, if you want to focus on what your friend is saying, then the voice of the person at the next table is noise because you would rather not hear it. When you are driving, the music playing on the radio or the sound of your car motor could be noise that interferes with paying attention to your passenger’s conversation. However, if you like the music playing on the radio in your car, or are worried that your car needs to be repaired, then the sound of your friend talking could be noise. You need your brain to ignore noise and pay attention to the sounds you want to hear. These choices depend on your goals in the situation and not simply on which sounds are entering your ears.
Remembering what you heard:
Remembering what a person said will be much easier if:
- it was easy to hear the words to begin with,
- the words made sense in the conversation and in the context of the situation, and
- you were able to focus your attention on what the talker was trying to tell you.
Again, the ears and the brain have to work together for the information coming into your ears to be stored in memory so that it can be used later.
How do ‘normal’ auditory and cognitive changes in healthy older adults affect listening in daily life?
In their 40s, adults often begin to notice problems understanding speech, especially in noisy or busy situations. These problems usually increase gradually over years or decades before a clinically significant hearing loss is diagnosed. Some people will have more problems than other people because they may be developing different type(s) of age-related hearing loss (see Part 3).
As adults age, there are also changes in cognition or how the brain works; some aspects of cognition get worse, but others get better (1). On the one hand, there are gradual cognitive declines over the adult lifespan in how well people process information. When people try to follow and understand a group conversation, they need to process the words that they hear. Fast and efficient processing of information, as in a conversation in a noisy room, involves hearing, but also understanding, focusing attention, and memory. Changes in the ear with age (auditory aging) can make it more difficult to listen. In turn, difficulty listening can reduce how efficiently the brain can understand, focus on and remember the information that was heard. In fact, people of any age have more difficulty understanding, focusing attention on and remembering when they listen in noisy situations compared to if they listen in a quiet situation. Importantly, the amount of noise that it takes to make listening difficult for an older adult is less than the amount that it takes to make listening difficult for a younger adult. Indeed, differences between younger and older adults on cognitive measures of comprehension or memory can be reduced or even eliminated if the listening conditions used during testing are adjusted so that it is equally difficult for younger and older adults to hear (2).
We learn to listen differently as we age:
It is possible for gains in some cognitive abilities to counter-act age-related declines in auditory information processing. There are gradual gains over the adult lifespan in knowledge of the world, linguistic knowledge (e.g., vocabulary), and other types of expertise. Even if hearing, focusing on and remembering information become progressively more difficult over the years, older adults can use their experience and knowledge to advantage when they listen. In other words, improved ability to use context and knowledge of the world can help an older listener to compensate. By compensating, older adults can continue to be successful in conversations and social interactions. This is especially the case in familiar situations where their knowledge can be a real strength. For example, being familiar with the topic being discussed can help a listener to compensate for difficulty hearing in noise. Compared to younger adults, older adults tend to rely more on their knowledge of the context and less on precisely hearing the sounds of speech. By using knowledge to compensate when it is difficult to follow conversation in noise, older adults may need to increase brain activity more than a younger adult would need to do . In the long term, in older adults who develop clinically significant hearing loss, there can be permanent changes in brain activation patterns and clinically significant cognitive declines may result (see Part 2). By solving hearing problems (see Part 4), you could make it easier to understand, focus your attention on and remember what you hear and in this way you will be taking some of the load off of your brain.
In this four-part blog post series we cover various aspects of hearing loss:
- In part 1, we discuss how changes in hearing and cognition (for example, memory) affect communication and social interactions in healthy older adults;
- in part 2, how hearing impairment may be related to cognitive impairment and dementia;
- in part 3, what hearing tests can and cannot tell you about your hearing problems; and
- and in part 4, when you should get your hearing assessed and what solutions might help you if you or your friends or family are having problems.