Brain changes caused by hearing loss can be slowed
When you start losing some hearing you are not only losing sound: your brain is changing irreversibly. But all is not lost.
by Jill Margo
Before David Ryugo sits down in a restaurant, he uses an app on his phone to measure the noise level. If it’s too high he usually leaves. He doesn’t do this because he is hard of hearing. Rather, he wants to avoid developing hearing problems.
“Noise is like radiation or ultraviolet light, “he says. ” A little won’t hurt but over time it accumulates and that’s what’s killing our ears. ”
Ryugo, professor of neuroscience at Sydney’s Garvan Institute and professor emeritus in hearing and balance at Johns Hopkins in United States, says the last decade of a man’s life is usually spent with hearing loss.
By the age of 70, some 75 per cent of men in industrialised countries will have significant hearing loss that not only affects their ability to communicate and their social relations, but causes changes in the brain that can’t be reversed.
The healthy human ear can hear an enormous range of sound, from softest whisper to a jet engine. Over this range it can determine very small changes from which the brain can make the finest distinctions.
When the brain is no longer receiving good stimulation, it alters its expectations and rewires itself. Some of the space it previously dedicated to hearing begins being used for other functions.
Ryugo says the brain doesn’t like a vacuum, and just as amputees suffer phantom limb pain, so hearing loss can give rise to phantom sounds such as tinnitus.
Knowing this, Ryugo takes every precaution he can. He carries earplugs in his pocket in case he is stuck in a noisy environment. If an ambulance speeds by with sirens blaring, he covers his ears with his hands. He does the same to muffle sound effects in the cinema and he no longer attends rock concerts.
MIND THE VACUUM CLEANER
It may sound excessive, but he is so conscious of the potential for cumulative damage that he will go to unusual lengths to protect his family, from covering the coffee grinder with a tea-cosy to testing how much noise a household appliance emits, before he buys it. “If you use a so-called ‘super-quiet’ vacuum cleaner for just 15 minutes, you’ve already done some damage,” he says.
He’s been protecting himself for more than 30 years and now has “pretty good” hearing for a man of 68. Regular checks have shown he has some loss in the high frequencies that can’t be regained or restored with a hearing device.
Unlike vision which is regularly checked and corrected, few people have their hearing checked. The family doctor might look in their ears occasionally for infection or wax, but their actual hearing goes unmeasured.
He describes hearing as the hidden sense, and says losing it can be slow and imperceptible. In a corporate setting, a negotiator may begin to miss the tonal subtleties of a voice, without ever realising it. In bed, the same man may never know how much whispered pillow talk he’s missing.
Typically, his partner will push and push until he agrees to have a hearing test. The test will detect noteworthy loss and then, Ryugo says, an extraordinary thing will happen. If he’s an average man, he’ll wait 10 years before acting on the advice to get a hearing aid fitted.
His resistance, usually driven by a combination of vanity and denial, exists in ignorance of the fact that hearing loss is progressive and that he will continue to lose it.
Ryugo’s work has shown intervention with a hearing aid can slow the loss and reduce the effects in the brain. He has demonstrated this in mice, and the model is now about to be tested in humans at Johns Hopkins University School of Medicine. The intervention stimulates the auditory system, which in turn prevents further unwanted brain changes.
Meanwhile, as the decade of denial passes, the resistant man’s quality of life will deteriorate. Initially he will cope by avoiding noisy restaurants. Then he won’t want to go to a dinner party he knows will be noisy. Eventually he won’t feel like going out much. Gradually he’ll become depressed, by which time he is at five times the risk of early-onset dementia.
By this stage he no longer urges others to “stop mumbling” or “speak clearly”. He’s even given up repeatedly asking “What?”. He’s retreated from grumpiness to isolation and as spontaneous communication is difficult, he’d rather read.
To people who have never protected their ears, Ryugo says start now. “If you’ve been to too many rock concerts, test for hearing loss and get it treated. Treatment consists of hearing aids, but you don’t need the $10,000 model. Get one for $2000 because it will give your brain the sound stimulation it needs.”
He says hearing aids do not work well in noisy environments because they directly address damage in the ear, not the consequent changes in the brain.
But there are solutions – such as pinning directional microphones on each guest around a table and then blue-toothing them to a hearing aid. Another option is for the hearing-impaired person to lay a microphone on their shoulder.
Some men wear high-end devices that are implanted on the ear drum and can’t be seen from the outside. These suffer the same drawbacks in loud places and they require major surgery, but have a cosmetic advantage and are good for pillow talk.
While many older Australians struggle with their hearing, he says some decades ago, when researchers tested a tribe of indigenous rural Africans, they found people in their 70s had perfect hearing.
For Australians the big risk factors are industrial noise, disease, drugs, chemicals and head trauma. The cancer drug cisplatin, the common antibiotic gentamicin and some non-steroidal anti-inflammatories are also ototoxic – dangerous to hearing.
Ryugo says a generation of people in China now have compromised hearing due to gentamicin, which is ubiquitous, effective, and cheap. It is still used in some circumstances in Australia and America.
In Australia, youth damage their hearing by pumping music loudly and directly into their ears via buds or earphones. “We are now seeing people in their 20s in need of hearing aids. If you can hear the music from their ear buds, you know they are already hard of hearing!”
And they are not alone. Last year the World Health Organisation said 1.1 billion teenagers and young adults were at risk of hearing loss due to the unsafe use of personal audio devices and exposure to damaging sound levels at sporting events and entertainment venues such as bars and nightclubs.
But rock music is not the only culprit. Modern gyms have such loud music that class instructors often use microphones to be heard above the noise.
Even orchestral music can be an issue. Last week a viola player sued the Royal Opera House claiming the sound from the brass immediately behind him in the pit peaked at roughly the same decibels as a jet engine and left him with acoustic shock.
He claimed this occurred during rehearsals for Wagner’s Die Walküre and with his hearing irreversibly damaged, his career was ruined.
If you think you have hearing loss, it’s worth seeing an ear specialist. Even with significant loss, you can develop strategies to stay socially engaged.
A professional will allow you to “test drive” a hearing aid on loan because only you will know which one sounds best. You might need multiple fittings to adjust it correctly. This is part of the “reality test” to preserve what is left of your hearing.
Hearing aids work best in the quiet and Ryugo says it’s important to have realistic expectations. The goal is to limit the progressive pathologic changes that occur in your brain and avoid social isolation.
But be alert, because although some audiologists are excellent, some are in it for profit and take advantage of vulnerable patients.
Contacting an advisory service, such as Better Hearing Australia, can be useful.