Posts tagged language disorders
Articles and news from the latest research reports.
UCSF Team Reveals How the Brain Recognizes Speech Sounds
UC San Francisco researchers are reporting a detailed account of how speech sounds are identified by the human brain, offering an unprecedented insight into the basis of human language.
The finding, they said, may add to our understanding of language disorders, including dyslexia.
Scientists have known for some time the location in the brain where speech sounds are interpreted, but little has been discovered about how this process works.
Now, in the Jan. 30 edition of Science Express, the fast-tracked online version of the journal Science, the UCSF team reports that the brain does not respond to the individual sound segments known as phonemes – such as the b sound in “boy” – but is instead exquisitely tuned to detect simpler elements, which are known to linguists as “features.”
This organization may give listeners an important advantage in interpreting speech, the researchers said, since the articulation of phonemes varies considerably across speakers, and even in individual speakers over time.
Teachers More Likely to Have Progressive Speech and Language Disorders
Mayo Clinic researchers have found a surprising occupational hazard for teachers: progressive speech and language disorders. The research, recently published in the American Journal of Alzheimer’s Disease & Other Dementias, found that people with speech and language disorders are about 3.5 times more likely to be teachers than patients with Alzheimer’s dementia.
Speech and language disorders are typically characterized by people losing their ability to communicate — they can’t find words to use in sentences, or they’ll speak around a word. They may also have trouble producing the correct sounds and articulating properly. Speech and language disorders are not the same as Alzheimer’s dementia, which is characterized by the loss of memory. Progressive speech and language disorders are degenerative and ultimately lead to death anywhere from 8-10 years after diagnosis.
In the study, researchers looked at a group of about 100 patients with speech and language disorders and noticed many of them were teachers. For a control, they compared them to a group of more than 400 Alzheimer’s patients from the Mayo Clinic Study on Aging. Teachers were about 3.5 times more likely to develop a speech and language disorder than Alzheimer’s disease. For other occupations, there was no difference between the speech and language disorders group and the Alzheimer’s group.
When compared to the 2008 U.S. census, the speech and language cohort had a higher proportion of teachers, but it was consistent with the differences observed with the Alzheimer’s dementia group.
This study has important implications for early detection of progressive speech and language disorders, says Mayo Clinic neurologist, Keith Josephs, M.D., who is the senior author of the study. A large cohort study focusing on teachers may improve power to identify the risk factors for these disorders.
"Teachers are in daily communication," says Dr. Josephs. "It’s a demanding occupation, and teachers may be more sensitive to the development of speech and language impairments."
(Image: Corbis)
New Treatments May Help Restore Speech Lost to Aphasia
Most people know the frustration of having a word on the “tip of your tongue” that they simply can’t remember. But that passing nuisance can be an everyday occurrence for someone with aphasia, a communication disorder caused by a stroke or other brain damage that impairs the ability to process language.
About 1 million Americans — roughly one in every 250 — are affected by aphasia, which can also impact reading and writing skills. But how they acquire the problem and how long they’ll endure it differ from person to person, explained Ellayne Ganzfried, a speech-language pathologist and executive director of the National Aphasia Association.
"No two people with aphasia are alike because everyone’s brain responds to the injury in a different way," Ganzfried said. "About half of people who have aphasia recover quickly, within the first few days. If the symptoms of aphasia last longer than two or three months, a complete recovery is unlikely … [though] some people continue to improve over a period of years and even decades."
Strokes are the most common cause, followed by head injuries, tumors, migraines or other neurological issues. Depending on the damage to the brain regions controlling language, which are typically in the left hemisphere, the resulting aphasia can be broken into four broad categories:
- Difficulty expressing thoughts through speech or writing
- Difficulty understanding spoken or written language
- Difficulty using the correct names for objects, people, places or events
- Loss of almost all language function, with no ability to speak or understand speech.
"Processing language requires the collaboration of lots of different parts or systems of the brain," explained Karen Riedel, director of speech-language pathology at the Rusk Institute of Rehabilitation Medicine at NYU Langone Medical Center in New York City. "The whole brain ‘talks’ — the whole brain has something to do with the use of language."
Because of this, a variety of therapies are used to help people regain as much speech and language as possible. But regardless of the injury, people with aphasia have the best chances for recovery when language therapy begins immediately, Riedel said.
Because aphasia is so variable, a therapy that helps one person might not help another, she noted. Tried-and-true techniques include melodic intonation therapy, which uses melody and rhythm to help improve the ability to retrieve words, and constraint-induced therapy, which forces people to use speech over other communication methods.
But technology, Riedel said, has introduced new language-improvement techniques into the mix over the last few years that are both exciting and fun. Several apps available for iPhone or iPad involve synthetic speech that helps engage those with aphasia in yet another realm of communication.
"Our patients have much more access to different kinds of programs that are computer-based," she said. "There’s always something new around the corner."
What remains a constant concern, however, is the misunderstanding many people have of those with language difficulties and how to treat them, Ganzfried and Riedel agreed.
"Many people with aphasia will become socially isolated because of their communication difficulties, which can lead to depression," Ganzfried said. "There are also many misconceptions about aphasia, including that the person is mentally unstable or under the influence of drugs or alcohol. It’s also extremely frustrating. Imagine knowing what you want to say in your head but you can’t get the words out."
(Source: consumer.healthday.com)