How do hearing loss and changes in the brain affect communication as we age?
“We observe a wide range of communication problems in older people,” says Dr. Bernhard Ross, senior scientist at the Rotman Research Institute at Baycrest. The loss of speech comprehension and communication in older adults are likely caused by several factors.
Almost everybody experiences some hearing loss, in particular for high pitch sound, during aging. Furthermore it becomes more difficult to hear the fine details in speech, which make the difference between words like ‘pill’ and ‘bill’. However, when we hear complete sentences such as ‘Did you pay the bill?’ or ‘Did you take the pill?’ we seem to have fewer problems understanding correctly.
The reason is that our brain helps fill in missing parts in sound and decides which words are most meaningful. As we age, those capabilities of central auditory processing and cognition may change, more time may be needed to find the right meaning of a sound we hear, and it may become more difficult to pay attention.
It appears as though more socially active seniors are better at communicating. However, the question is are people better at communicating because they are socially active or is it possible that people give up social activity because of a communication problem?
Dr. Ross is studying how hearing may affect our ability to communicate as we age. More specifically, he is looking at binaural hearing in the elderly. “Using both ears most people can hear which direction a sound is coming from,” explains Dr. Ross. “A sound from the right side reaches the right ear a little earlier than the left ear. With increasing age, we may no longer be able to hear those slight differences. We are looking into how this affects communication and speech.
“It appears as though when we are younger our brain allows us to attend to one sound and ignore the other. This ability tends to decrease as we age. Obviously, hearing with both ears is important in a hazardous situation such as driving or crossing the street. In social situations, such as the dinner table, when there may be more than one conversation taking place, we can identify different speakers by their voices coming from one or the other direction. When we loose the ability to localize the sounds, everything becomes mixed and incomprehensible.”
Hearing loss is a very common effect during aging and this loss can be helped with hearing aids. Hearing aids work best in quiet environments. During one-on-one communication they restore hearing perfectly.
However, hearing aids also amplify noise. In a noisy situation, those using hearing aids often complain “I can hear you, but I can’t understand you”. Those experiences might be so unpleasant that occasionally people withdraw from wearing the hearing aids.
Using Magnetoencephalography (MEG) technology, scientists at Baycrest are investigating which areas of the brain are active while performing various tasks. With the MEG, scientists can measure magnetic fields of brain activity from outside of the head. This enables the scientists to locate the brain areas associated with perceiving different types of objects with the eyes, ears or by touch. They can also identify those regions of the brain which are involved in decision-making, emotion, learning and more. Also they can precisely measure when these brain regions are active.
Participants in the study are placed in a shielded room which blocks out environmental noises. After a few small coils are attached to the head, the MEG, a unit which has the shape of a large helmet, is placed over the head.
“Our findings indicate that the frequency range in which we can localize sound decreases as we age,” explains Dr. Ross. “We did this experiment with three age groups – young (20-30 years), middle-aged (45-55 years) and older (65-75 years). There were no differences in hearing the sounds themselves, but detecting small differences between sound in the left and right ear became more difficult with increased age. This difficulty was already obvious in middle aged participants.”
“As we age, there are a number of changes in our hearing system and in the brain. I believe that the sum of these changes may result in problems with communication,” says Dr. Ross.
Clinicians and scientists are beginning to work together to find integrated approaches for improving speech communication in older adults. Some of these approaches include modifying the content of the incoming speech signal in hearing aids, as well as engaging focused listening and training exercises.
Even without such technology, often simple steps may help to improve speech conversation such as speaking slowly, using short straightforward sentences, and avoiding noisy and reverberating environments.
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