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In the News, Neuroscience, otolaryngology

Say that again? Tone deafness is inherited, study finds

Say that again? Tone deafness is inherited, study finds

singing2Can’t carry a tune? Don’t spend all your money on music lessons: Turns out tone deafness is an inherited non-talent.

Leonard Bernstein (no, not that one) writes in The Checkup:

Finnish researchers say they have found genes responsible for auditory response and neuro-cognitive processing that partially explain musical aptitude. They note “several genes mostly related to the auditory pathway, not only specifically to inner ear function, but also to neurocognitive processes.”

“Humans have developed the perception, production and processing of sounds into the art of music. A genetic contribution to these skills of musical aptitude has long been suggested,” the researchers note in the study. Using a genome-wide scan, researchers evaluated 767 individuals “for the ability to discriminate pitch (SP), duration (ST) and sound patterns (KMT), which are primary capacities for music perception.” The study was published in Molecular Psychiatry.

Previously: Music that comes straight from the soul…er, DNA
Photo by Kathleen Tyler Conklin

otolaryngology, Research, Stanford News, Stem Cells

Understanding hearing loss at the molecular level

Understanding hearing loss at the molecular level

baby earDeep inside the ear, specialized cells that are confusingly called “hair cells” – they have nothing to do those hairs protruding from your Uncle Fred’s ears – detect vibrations in the air and translate them into sound. Without them, you can’t hear. Unlike non-mammalian species, in humans, there are a limited number of these cells, and if enough of them get damaged or killed off, hearing loss occurs.

Hair cells are the key to understanding the process of hearing. By figuring out how these cells work at a molecular level, scientists believe they can eventually develop better treatments and possible cures for deafness. Key to this goal is figuring out how to regenerate these cells if they get damaged or die off.

A new Stanford study published in the journal Development takes one more step along this pathway by showing that these early hair cells can be grown back in newborn mice.

“The study builds on the hypothesis that younger cochlea – that portion of the inner ear where the hair cells are located – can regenerate,” said Alan Cheng, MD, one of the senior authors of the study, which was done in collaboration with St. Jude Children’s Research Hospital.

“No spontaneous auditory hair cell regeneration has been observed in postnatal mammals prior to this study,” Cheng, an assistant professor of otolaryngology and pediatrics, told me. “Extensive efforts from laboratories around the world have focused on understanding mechanisms that can drive mammalian hair cell regeneration.”

In their study, the scientists induced hair cell loss in their mouse models at birth and then observed there was “spontaneous regeneration of hair cells.” One week after birth, there was no much regeneration.

The research also showed, interestingly, that most of these regenerated hair cells in the young cochlea didn’t ultimately survive. “This lack of survival posits a new challenge to regenerating hearing,” Cheng said.

Previously: Battling hearing loss on and off the battlefield, Stanford researchers gain new insights into how auditory neurons develop in animal study, Stanford hearing study upends 30-year-old belief on how humans perceive sound and Stanford chair of otolaryngology discusses future regenerative therapies for hearing loss
Photo by boltron-

otolaryngology, Podcasts, Research, Stanford News

Listening to elephants, communicating science, and inspiring the next generation of researchers

Listening to elephants, communicating science, and inspiring the next generation of researchers

Caitlin O’Connell-Rodwell, PhD, is an instructor in Stanford’s Department of Otolaryngology and a scientist who studies, among other things, how elephants hear. In this just-published Neurotalk podcast, Rodwell discusses her studies from the field, including how elephants use foot stomping and low-frequency vocalizations to communicate. “If you think of the earth as a trampoline and you have this 10-ton animal on the earth running, you’re going to create a huge wave,” she said of the seismic vibrations they create. Elephants can also use their big ears, and comparatively large malleus middle-ear bone, to hear, and draw still to listen, she noted.

The podcast details O’Connell-Rodwell’s contributions to science as a writer and instructor of science communications at Stanford and for the New York Times, as well as her mission to encourage girls to pursue the hard sciences. She said:

As a woman in science, especially doing a little bit of physics, if you don’t have a role model it’s very difficult to try to imagine yourself [there]. So I got interested to get girls interested in the hard sciences because there’s no reason why they shouldn’t be there.

You have to get kids excited about science… One of the things that got me interested in entymology to begin with was that childlike enthusiasm for the miniature and the unknown.

She added, “In our minds it’s a story, but it’s not obvious to everyone else.”

Previously: Elephants chat a bit before departing water hole, new Stanford research shows and Researcher dishes on African elephant soap opera
Photo in featured entry box by Caitlin O’Connell-Rodwell and Timothy Rodwell

otolaryngology, Patient Care, Pediatrics, Stanford News, Technology

Baby steps: Therapy that helps the deaf to hear

Baby steps: Therapy that helps the deaf to hear

Baby TalkWhat better way to highlight how cochlear implants work than by sharing the story of 1-year-old Lucile Ross, an utterly adorable participant in Stanford’s growing new “teletherapy” program called BabyTalk?

In an Inside Stanford Medicine story published today, I write about the severely hearing-impaired Lucile and the program that helps her and 17 other toddlers learn to use their surgically imbedded cochlear implants to listen and speak. I describe what happened one day in June, about a month after her implant was first activated, when Lucile was busily eating Cheerios and suddenly grabbed her ear in astonishment. She had just heard something, prompting her hearing therapist to comment, “That was beautiful.”

My story goes on to discuss the technology behind the implants, the kinds of “sounds” that the tiny patients first hear, and how the children begin to interpret these sounds and learn how to speak:

A cochlear implant is an electronic device. One part includes electrodes that have been surgically implanted in the inner ear; another part, which sits outside the ear, includes a microphone. It can help the profoundly deaf and severely hard of hearing learn to listen and speak, and is particularly successful if implanted prior to the age of 3. The first three years after a child is born is the most critical period for the development of speech and language.

The device works by electronically transporting sounds from the microphone, which sits behind the ear, to the inner electrodes, which stimulate the auditory nerves and send sound information to the brain. The device doesn’t restore normal hearing; new recipients have described what they “hear” as sounding robotic or like ducks quacking, or just plain weird. Instead, it can give a deaf person a useful representation of sounds in the environment and help him or her to understand speech. But in order to do that, training is needed.

BabyTalk delivers that training – via the iPad – to geographically isolated patients and their families. For my story, I joined Lucile’s teacher, Sharon Nutini, at the Jean Weingarten Peninsula Oral School for the Deaf in Redwood City, Calif., Stanford’s partner in the BabyTalk program, for one of the virtual lessons with Lucile and her dad, Lyle, at home in Marin County. I had to agree with what Lucile’s mother had earlier told me over the phone: Watching Lucile learn to speak is an amazing experience. More from the piece:

 ”She’s giving us signs that she understands us, that she’s learning language,” Lizzie Ross said. “We think that she’s going to catch up quickly. Sharon gives us exercises that we do during the week. We sing songs that elicit certain language, we work on the recognition of animal sounds — the dog barking. There’s a lot of repetition, a lot of fun play stuff with her own toys — just what she would normally do on a daily basis.

“We knew it would be a hurdle. But for us, it’s been worth every minute of it. We were lucky that the opportunity was out there for her to hear and develop speech at a young age. It’s been a pretty amazing experience.”

Previously: Using the iPad to connect ill newborns, parents, “What’s that?” Stanford researchers identify cells important to hearing lossCochlear implants could help developmentally delayed infants, says Stanford/Packard study and  In people born deaf, auditory cortex takes on touch and vision, study finds
Photo of Lucile and her father, Lyle, by Norbert von der Groeben

otolaryngology, Research, Stanford News, Videos

Stanford-developed probe aids study of hearing

Stanford-developed probe aids study of hearing

Stanford engineers and medical researchers have developed a tiny tool known as a force probe to study sensory cells in the ear, as Anthony Peng, PhD, a postdoctoral research fellow in otolaryngology, and Anthony Ricci, PhD, professor of otolaryngology, discuss in this brief video. A Stanford News article provides more details on this Bio-X project and how, in contributing to scientists’ understanding of how we interpret sound, the findings could inform new ways of treating some forms of hearing loss.

Previously: Stanford hearing study upends 30-year-old belief on how humans perceive soundStanford researchers gain new insights into how auditory neurons develop in animal studyStanford chair of otolaryngology discusses future regenerative therapies for hearing loss and Stanford engineer studies bones that aid hearing

otolaryngology, Research, Science, Stanford News

Stanford researchers gain new insights into how auditory neurons develop in animal study

Stanford researchers gain new insights into how auditory neurons develop in animal study

The auditory system of newborn mammals is still developing when a baby mouse – or a baby human – is born. Mice are born deaf and don’t start hearing until the twelfth day of life. In a study published Monday in PNAS, Stanford researchers report that new auditory neurons are not only being developed in the first month of life, but continue to develop in juvenile mice.

Whether these results can be applied to our understanding of the hearing process in humans is still speculative at this point, says the senior author of the paper, Stefan Heller, MD, PhD. But they could helpful in understanding how hearing develops in children. Heller wrote in an e-mail:

We all know that the human brain is highly plastic in the first years of life. Babies, toddlers and preschool children learn with a speed that is unprecedentedly efficient and plasticity is certainly highly involved when children acquire for example the ability to speak.

Hearing and the fine tuning of sound perception plays a major role in this. A child that is born deaf will have an incredibly difficult time to learn speech unless the auditory system is stimulated, for example, with a cochlear implant.

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Evolution, otolaryngology, Research, Stanford News

Stanford engineer studies bones that aid hearing

Stanford engineer studies bones that aid hearing

What distinguishes us from the dinosaurs? Three middle ear bones, for starters. Stanford mechanical engineer Sunil Puria, PhD, studies inner- and middle-ear biomechanics and the role of bone conduction in hearing, and he’s among a number of scientists who are curious why we have the tiny malleus, incus and stapes but reptiles and birds don’t.

Read more from Stanford Report on what Puria’s research on bone conduction hearing could mean for treating hearing loss, enhancing sound technology, and understanding evolutionary biology.

Previously: Battling hearing loss on and off the battlefield and Hearing loss patient discusses why Stanford research gives her hope for an eventual cure

otolaryngology, Patient Care, Research, Stanford News

Battling hearing loss on and off the battlefield

Battling hearing loss on and off the battlefield

detonationThe loud blasts from improvised explosive devices, or IEDs, in war zones is causing an uptick in hearing loss among soldiers and has gotten the U.S. Department of Defense concerned. Twenty-eight percent of all military personnel experience some degree of hearing loss post-deployment.

But new research out of Stanford shows that much of what was believed to be permanent hearing loss from loud blasts such as these may actually be reversible.

In a press release I wrote about this DOD-sponsored study, I describe the hopeful results:

Using a mouse model, the study found that loud blasts actually cause hair-cell and nerve-cell damage, rather than structural damage, to the cochlea, which is the auditory portion of the inner ear. This could be good news for the millions of soldiers and civilians who, after surviving these often devastating bombs, suffer long-term hearing damage.

The senior author of the study, John Oghalai, MD, associate professor of otolaryngology at Stanford, said that not all of the damage occurs immediately after the explosion. More damage occurs as the body’s immune system tries to heal the injury. The creation of scar tissue to help heal the injury is a particular problem in the ear because the organ needs to vibrate to allow the hearing mechanism to work:

With one loud blast, you lose a huge number of (hearing) cells. What’s nice is that the hair cells and nerve cells are not immediately gone. The theory now is that if the ear could be treated with certain medications right after the blast, that might limit the damage.

Oghalai said that the surprising results have determined the course of new research looking into ways of reversing or blocking further hearing loss. He told me:

There is going to be a window where we could stop whatever the body’s inflammatory response would be right after the blast. We might be able to stop the damage.

Previously: Hearing loss patient discusses why Stanford research gives her hope for an eventual cure, “What’s that?” Stanford researchers identify cells important to hearing loss, Regenerating sensory hair cells to restore hearing to noise-damaged ears, Stanford researcher comments on the use of human embryonic stem cells to restore hearing and Growing new
inner-ear cells: a step toward a cure for deafness

Photo by adamhenning

otolaryngology, Research, Stanford News

Hearing loss patient discusses why Stanford research gives her hope for an eventual cure

Hearing loss patient discusses why Stanford research gives her hope for an eventual cure

Over on the Stanford Initiative to Cure Hearing Loss blog, Nat Lauzon, a voiceover artist and radio DJ, shares her personal story of living with hearing loss. Lauzon began having difficulty hearing at the age of 15, but didn’t let the condition stop her from forging out a career in industries that rely heavily on hearing. Earlier this year, she read about Stanford researchers identifying a class of cells called tympanic border cells that can give rise to hair cells and the cells that support them during a phase of cochlear maturation right after birth.

The findings inspired her to become a supporter of the Stanford Initiative to Cure Hearing Loss and gave her hope that the research may lead to discoveries that could one day help the millions of Americans suffering from hearing loss due to damaged or impaired sensory hair cells. She writes:

I was amazed, appreciative, inspired.  A cure for hearing loss is a potentiality that is actually within the reach of science! This is huge! I  immediately donated and sent along a note of thanks, explaining my personal situation and why a cure would mean so much to me.  It’s actually how this blog post came to fruition.

For me, a cure would mean the ability to continue my passion in life. To not worry about what’s around the corner for me or what the audiogram will say in another 10 years’ time. But honestly, the bigger picture is just as meaningful to me. To know the lives of millions of people – from babies to toddlers to adults -with profound hearing loss and deafness would be forever changed? I consider that, not only a marvel but a miracle of science.

My hope is that I can help be part of a larger picture of optimism and awareness:  not only for hearing health in the radio profession, but also to help tear away the general stigma of hearing loss as merely an “old people” affliction. And, along with that – draw support for the incredible and groundbreaking work that is being done by Stanford to find a cure.

Previously: “What’s that?” Stanford researchers identify cells important to hearing loss, Regenerating sensory hair cells to restore hearing to noise-damaged ears, Stanford researcher comments on the use of human embryonic stem cells to restore hearing and Growing new inner-ear cells: a step toward a cure for deafness
Photo by cursedthing

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