Category Archives: Hearing

Motorcycle Helmets Hard on Hearing

Reference: The ASHA Leader (Oct. 11, 2011)

The distinctive roar of a motorcycle engine is loud, but studies have revealed the biggest source of noise for motorcyclists is generated by air whooshing over their helmets.  Even at legal speeds, the sound can exceed safe levels.  Researchers in the United Kingdom placed motorcycle helmets on mannequin heads, mounted them in a wind tunnel, and turned on fans.  By placing microphones at different locations around the helmet and at  the mannequin’s ear, researchers found that an area underneath the helmet and near the chin bar is a significant source of the noise that reaches rider’s sensitive eardrums.  Future tests will move beyond the wind tunnel to riders on the open road.  The findings, described in the Journal of the Acoustical Society of America, may lead to quieter helmet design.  Search “hard on hearing” at www.aip.org/aip.

Mild Hearing Loss

Reference: Advance for Speech-Language Pathologists and Audiologists (Oct. 3, 2011)

Mild Hearing Loss
Linked to brain atrophy in older adults

Declines in hearing ability may accelerate gray matter atrophy in auditory areas of the brain and increase the listening effort necessary for older adults to comprehend speech successfully, a new study has shown.  When a sense is altered, the brain reorganizes and adjusts.  In the case of people with poor hearing, researchers found that the gray matter density of the auditory areas was lower in people with decreased hearing ability, suggesting a link between hearing ability and brain volume.

“As hearing ability declines with age, interventions such as hearing aids should be considered not only to improve hearing but to preserve the  brain,” said lead author Jonathan Peelle, PhD, a research associate in the Department of Neurology, Perelman School of Medicine, at the University of Pennsylvania in Philadelphia.  “People hear differently, and those with even moderate hearing l0ss may have to work harder to understand complex sentences.”

In a pair of studies, researchers measured the relationship of hearing acuity to the brain, first measuring the response of the brain to increasingly complex sentences and then measuring cortical brain volume in the auditory cortex.

Older adults, ages 60-77, with normal hearing for their age were evaluated to determine whether normal variations in hearing ability impacted the structure or function of the network of brain areas supporting speech comprehension.

The studies found that people with hearing loss showed less brain activity on functional magnetic resonance imaging (fMRI) scans when listening to complex sentences. People with poorer hearing also had less gray matter in the auditory cortex, suggesting that areas of the brain related to auditory processing may show accelerated atrophy when hearing ability declines.

In general, research suggests that hearing sensitivity has cascading consequences for the neural processes supporting both perception and cognition.  Although the research was conducted in older adults, the findings have implications for younger adults, including those concerned about listening to music at loud volumes.

“Your hearing ability directly affects how the brain processes sounds, including speech,” said Dr. Peelle.  “Preserving your hearing doesn’t only protect your ears but also helps your brain perform at its best.”

Audiologists should monitor hearing in patients as they age, noting that individuals who still fall within normal hearing ability may have increasing complaints of speech comprehension issues.

Grants from the National Institutes of Health funded the research.

Peele, J.E., Troiani, V., Grossman, M., et al. (2011).  Hering loss in older adults affects neural systems supporting speech comprehension.  The Journal of Neuroscience, 31 (35): 12638-43

 

Study Digs Deeper into Dyslexia

Reference:  St. Louis Post Dispatch August 4, 2011

Disorder has roots in failure to recognize the sounds of speech.
by Pam Belluck New York Times

Many people consider dyslexia simply a reading poblem in which children mix up letters and misconstrue written words.  But scientists increasingly have come to believe that the reading difficulties of dyslexia are part of a larger puzzle: a problem with how the brain processes speech and puts together words from smaller units of sound.

Now, a study published last week in the journal Science suggests that how  dyslexics hear language may be more important than previously realized.  Reasearchers at the Massachusetts Institute of Technology have found that people with dyslexia have more trouble recognizing voices than those without dyslexia.

John Gabrieli, a professor of cognitive neuroscience, and Tyler Perrachione, a graduate student, asked people with and without dyslexia to listen to recorded voices paired with cartoon avatars on computer screens.  The subjects tried matching the voices to the correct avatars speaking English and then an unfamiliar language, Mandarin.

Nondyslexics matched voices to avatars correctly almost 70 percent of the time when the language was English and half the time when the language was Mandarin.  Experts not involved in the study said that was a striking disparity.

“Typically, you see big differences in reading, but there are just subtle general differences between individuals who are afflicted with dyslexia and individuals who aren’t on a wide variety of tests,” said Richard Wagner, a psychology professor at Florida State University.  “This effect was really large.”

Sally Shaywitz, a director of the Center for Dyslexia and Creativity at Yale University, said the study “demonstrates the centrality of spoken language in dyslexia-that it’s not a problem in meaning, but in getting to the sounds of speech.”

That is why dyslexic children often misspeak, she said, citing two examples drawn from real life.

“A child at Fenway Park watching the Red Sox said, ‘Oh, I’m thirsty. Can we go to the confession stand?’ ” she said.  “Another person crossing a busy intersection where many people were walking said, ‘Oh, those Presbyterians should be more careful.’  It’s not a question of not knowing but being unable to attach what you know is the meaning to the sounds.”

Gabrieli said the findings underscored a critical problem for dyslexic chidlren learning to read: the ability of a child hearing, say, a parent or teacher speak to connect the auditory bits that make up words, called phonemes, with the sight of written words.

If a child has trouble grasping the sounds that make up language, he siad, acquiring reading skills will be harder. 

The research shows that spoken language deficiencies persist even when dyslexics learn to read well.  The study subjects were mostly “high-functioning, high-IQ young adults who had overcome their reading difficulty,” Gabrieli said.  “And yet when they had to distinguish voices, they were not one iota better with the English-language voices that they’ve heard all their life.”

Experts said the new study also shows the interconnectedness of the brain processes invoiced in reading.  Many scientists had considered voice recognition to be “like recognizing melodies or things that are primarily nonverbal,” Gabrieli said.

Voice recognition was thought to be a separate task in the brain from understanding language.

But this research shows that normal reading involves a “circuit, the ability to have all of those components integrated absolutely automatically,” said Maryanne Wolf, a dyslexia expert at Tufts University.  “One of the great weaknesses in dyslexia is that the system is not able to integrate these phoneme-driven systems” with other aspects of language comprehension.

Any questions or comments about this article are welcome at www.interactivetherapy.net!

To start the discussion:

A speech language pathologist is often involved with a child’s articulation and/or phonological disorder at earlier ages before a child starts to read.  One cannot predict if a child with an articulation or phonological disorder will have a reading/writing problem.  It behooves us as educators and speech language pathologists to monitor a child’s development in reading and writing for those children who may be at risk for dyslexia because of difficulty in perceiving, processing and producing sounds in speech.  If anyone is doing research on predicting dyslexia based on articulation/phonological disorders, please let me know.  It would be a worthwhile study.  It would be good to know if  those of us working in the field of speech language pathology could lessen the degree of dyslexia before a child learns to read/write or even prevent it. 
Pam Hass, Interactive Therapy Inc

Early fitting for Later Benefits

Reference:  American Speech and Hearing Association Leader
July 5, 2011

Elderly persons fitted with hearing aids during the early stages of hearing loss may retain cognitive function better than those who are fitted later for hearing aids.  In a study conducted at the International University of Health and Welfare in Tochigi, Japan, participants were divided into three groups: a typically hearing group, a hearing-loss-without-hearing-aids group, and a hearing-loss-with-hearing-aids group.

On tests of pure-tone audiometry, syllable intelligibility, dichotic listening, and the Wechsler Adult Intelligence Scale-Revised (WAIS-R) Short Forms, the hearing-loss-without-hearing-aids group showed the lowest scores on all measures.  These results indicate that acquiring a hearing aid in the initial stages of hearing loss may lead to greater retention of cognitive skills in elderly people.  However, the lack of statistically significant correlations between the auditory and cognitive tests suggests that further studies are warranted to address this question more definitively.  Search “Obuchi” at http://audiologyresearch.org.

Please click on comment for further discussion on this topic.

Making Kids Safe In Sound

As iPod or MP3 use among children grows at an unprecedented rate fueling concerns that many are using the technology unsafely, the American Speech-Language-Hearing Association’s (ASHA) Listen to Your Buds website (www.listentoyourbuds.org) aims at empowering parents and protecting children from noise-induced hearing loss and other communication difficulties.

Protect your child’s hearing by teaching three basic principles: keeping the volume down, limiting listening time, and watching for warning signs of hearing loss.