Johns Hopkins Discovers New Path to Treating Age-Related Hearing Loss – “There’s More to Hearing Than the Ear”

Ear Hearing Concept

Researchers at Johns Hopkins Medicine have found that old mice are less able than young mice to “turn off” certain actively firing brain cells in the presence of ambient noise. This results in a “fuzzy” sound stage that makes it difficult for the brain to focus on a specific sound and filter out surrounding noise. The researchers suggest that age-related hearing loss may be treated by retraining the brain to reduce the activity of these neurons.

Study of hearing in old and young mice suggests the brain might be trained to filter out background sound.

Looking for answers about how the brain works amid age-related hearing loss, Johns Hopkins Medicine researchers discovered that old mice were less capable than young mice of “turning off” certain actively firing brain cells in the midst of ambient noise. The result, they say, creates a “fuzzy” sound stage that makes it difficult for the brain to focus on one type of sound — such as spoken words — and filter out surrounding “noise.”

Scientists have long linked inevitable age-related hearing loss to hair cells in the inner ear that become damaged or destroyed over time.

But the Johns Hopkins researchers say their new studies, described on December 7 in The Journal of Neuroscience, indicate that the brain has much to do with the condition, and it may be possible to treat such hearing loss by re-training the brain to tamp down the wildly firing neurons.

Older Man Hard of Hearing

When grandpa can’t hear words at a noisy holiday gathering, too many brain cells may be firing at once, say researchers.

“There’s more to hearing than the ear,” says Patrick Kanold, Ph.D., professor of biomedical engineering at The Johns Hopkins University and School of Medicine. Kanold notes that most people will experience some kind of hearing loss after age 65, like the inability to pick out individual conversations in a bar or restaurant.

Kanold and his team recorded the activity of 8,078 brain cells, or neurons, in the auditory cortex brain region of 12 old mice (16–24 months old) and 10 young mice (2–6 months old).

First, the researchers conditioned the mice to lick a water spout when they heard a tone. Then, the same exercise was performed while playing “white noise” in the background.

Without the ambient noise, the old mice licked the water spout just as well as the young mice when they heard the tone.

When the researchers introduced the white noise, overall, the old mice were worse at detecting the tone and licking the spout than the young mice.

Also, the young mice tended to lick the spout at the onset or the end of the tone. Older mice licked it at the start of the tone cue but also showed licking before the tone was presented, indicating that they thought a tone was present when there wasn’t one.

Next, to see how auditory neurons performed directly during such hearing tests, the researchers used a technique called two-photon imaging to peer into the auditory cortex in the mice. The technique uses fluorescence to identify and measure the activity of hundreds of neurons at the same time.

Under normal conditions, when brain circuitry worked correctly in the presence of ambient noise, some neuron activity increased when the mice heard the tone and, at the same time, other neurons became repressed, or turned off. In most of the old mice, however, the balance tipped to having mostly active neurons, and the neurons that were supposed to turn off when the tone was played in the presence of a noisy background failed to do so.

In addition, the researchers found that just before the tone cue, there was up to twice as much neuron activity in old mice than young mice, especially among males, causing the animals to lick the spout before the tone start.

A possible reason for that result, Kanold says, is that “in the old mice, the brain may be ‘firing’ or behaving as if a tone is present, when it’s not.”

The experiments with ambient noise also revealed that young mice experienced shifts in the ratio of active to inactive neurons, while older mice had more consistently active neurons overall. Thus, young mice could suppress the effects of ambient noise on neural activity while old mice could not, say the researchers.

“In older animals, ambient noise seems to make neuron activity more ‘fuzzy,’ disrupting the ability to distinguish individual sounds,” says Kanold.

On the upside, Kanold believes that because of the mammalian brain’s flexible learning potential, it can be “taught” to address the fuzziness in older animals, including humans.

“There may be ways to train the brain to focus on individual sound amid a cacophony of noise,” he says.

Kanold notes that more research is needed to precisely map the connection between the inability to shut off certain neurons and hearing loss amid ambient sound, including the brain circuits involved and how they change with age, as well as the potential differences between male and female animals.

Reference: “Decreased Modulation of Population Correlations in Auditory Cortex Is Associated with Decreased Auditory Detection Performance in Old Mice” by Kelson Shilling-Scrivo, Jonah Mittelstadt and Patrick O. Kanold, 7 December 2022, Journal of Neuroscience.
DOI: 10.1523/JNEUROSCI.0955-22.2022

Other contributors to the research are Kelson Shilling-Scrivo and Jonah Mittelstadt from the University of Maryland.

Funding for the research was provided by the National Institutes of Health (P01AG055365, RO1DC009607, RO1DC017785).

29 Comments on "Johns Hopkins Discovers New Path to Treating Age-Related Hearing Loss – “There’s More to Hearing Than the Ear”"

  1. I would be interested in any human medical research studies.

  2. as a human with hearing loss, all i can say to this is, “duh?”
    all input has to be interpreted by the brain in the context of stored data and we know the brain prunes pathways to be energy efficient and keep the organism alive. the quantity and volume of sound input is unrelenting. reduce the cacophony.

  3. I would be interested in participating in a study to help prove this research.

  4. How can I become involved in clinical trials

  5. Randolph Draughorne | December 25, 2022 at 10:05 pm | Reply

    I am interested in participating in this study. I have had hearing loss since 2018. I am 64yrs old and was in 2018 that my SNHL was caused by dead hearing hair cells.

  6. Where do i sign up

  7. Interested parties may also wish to investigate Frequency Therapeutics, a company working to reverse hearing loss.

  8. I am deaf in my left ear since 4 years old. My ear drum burst due a high fever. I have had 2 hearing implants. It’s not working my body keeps rejecting it. 1st implant Baha and now the Medel.

  9. As sound is in the brain of the beholder..

  10. Dinora Cavazos Osuna | December 26, 2022 at 10:40 am | Reply

    I recently went to Colorado and I was at 9500 feet above level I didn’t have no ringing in my ears. I slept so good I don’t know if it was the altitude or what, but as soon as we got to Colorado Springs, I started hearing the ringing on my ears.

  11. I am also having trouble distinguishing sounds and have an auditory analysis record. I would be happy to participate. I am in the San Francisco Bay Area.

  12. If there are clinical trials for hearing issues,I would be interested.

  13. Let me no the results…

  14. Count me in for trials…. Hearing problems my whole life.

  15. Verdinand Karel de Waal | December 26, 2022 at 6:09 pm | Reply

    I am 74 years old and would love to better my hearing loss. Hearing aid not working for me. Please help
    From South Africa

  16. Ear infections as a child led to eardrum replacements almost 20 years ago. Now in 2022 ear problems are leading to hearing loss. Any help or answers would be welcome

  17. Yvonne L Briscoe | December 27, 2022 at 3:30 am | Reply

    My husband lose his hearing from a stroke. He wears hearing aides. But he also has Aphasias.
    Will this help my husband 🙏🏽🙏🏽

  18. Myriam Kaplan-Pasternak | December 27, 2022 at 10:09 am | Reply

    I would be interested in participating in a study. I have hearing loss with aging and genetic tinnitus. I can often block out the ringing but I can’t filter background noises to better hear voices.

  19. I’d love to participate in this research. I have heating loss in both ears. I’m 69 years old and started to lose my hearing at 49.

  20. Q: Would it be possible that people at older age, perhaps starting as “early” as in their fifties or even earlier, also develop – or at least experience – episodes of temporary aphasia. In certain situations – input overload, unfavorable ambiance,…, one perfectly hears a sentence spoken but – it does not leave any recognizable “trace.” No “interpreter” of the meaning of the sentence kicks in, at least not immediately.

  21. I would like to volunteer for this study also. The fuzzy sound is very annoying.

  22. Also, the young mice tended to lick the spout at the onset or the end of the tone. Older mice licked it at the start of the tone cue but also showed licking before the tone was presented, indicating that they thought a tone was present when there wasn’t one.

    Anyone else get the idea that the researchers assume old mice don’t get “ringing in the ears”. Several of the observation in this article would be explained by ringing in the ears but they don’t seem to take that into account.

  23. Peabody McCallister | December 28, 2022 at 7:25 pm | Reply


  24. This information seems so promising for those who have hearing loss. Thanks for posting this! I
    have age related hearing loss and also unrelenting tinnitus. I have hearing aids and they don’t help my hearing loss or my tinnitus. I was thinking it could be my brain as in Cognitive Auditory Processing Disorder. I also have mild aphasia and difficulty recalling words when I talk. Any hope for improving my brain and hearing would be fantastic! I’m 68 years old.

  25. I am 70 and have hearing loss more in left ear than right .
    Tinnitus is bad . Like stereo . I had a hit on back of my head at about 21 and a few years later started having seizures. In my sleep mostly. I had a severe seizure after going up and down elevators on a job orientation . Had to have assistance. I later went to hospital and was told it was an electrical short causing my feelings , twinges mostly . I took medication to help with seizures and it eventually healed itself. No problems since except tinnitus and hearing loss.
    I have always done loud things in lawn maintenance and tree trimming without hearing protection.
    I would pray that I could be healed through the hands of researchers. Thankfully even with this problem, I have been healthy my whole life.
    Dad is still going at 91 but almost dead .
    Thanks for reading. One day we will all be healed !

  26. Thank you to science and scientific studies for taking the time to help hundreds of thousands people around world dealing with so call “tinnitus”
    Hopefully in the near future there will be a treatment to stop ringing, buzzing. Again thank you. Open to participate in clinical studies

  27. I’m a 100% SERVICE CONNECTED DISABLED VETERAN. I have real bad hearing loss. I wear hearing aids. The hearing aids that I get at the VA don’t really help me in hearing conversations. The background noise is always louder. I would like to participate in your studies if it’s going to help me with my hearing loss.

  28. Robert Calderone | December 31, 2022 at 7:02 pm | Reply

    I would be interested in participating in a study regarding severe Tinnitus.

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