Strengthening speech networks to treat aphasia
The waveforms of two similar sounding syllables "ta" and "da" allow researchers to make precise time measurements and comparisons of speech production. Credit: Blumstein lab/Brown University
Aphasia, an impairment in speaking and understanding language after a stroke, is frustrating both for victims and their loved ones. In two talks Saturday, Feb. 16, 2013, at the conference of the American Association for the Advancement of Science in Boston, Sheila Blumstein, the Albert D. Mead Professor of Cognitive, Linguistic, and Psychological Sciences at Brown University, will describe how she has been translating decades of brain science research into a potential therapy for improving speech production in these patients.
About 80,000 people develop aphasia each year in the United States alone. Nearly all of these individuals have difficulty speaking. For example, some patients (nonfluent aphasics) have trouble producing sounds clearly, making it frustrating for them to speak and difficult for them to be understood. Other patients (fluent aphasics) may select the wrong sound in a word or mix up the order of the sounds. In the latter case, "kitchen" can become "chicken." Blumstein's idea is to use guided speech to help people who have suffered stroke-related brain damage to rebuild their neural speech infrastructure.
Blumstein has been studying aphasia and the neural basis of language her whole career. She uses brain imaging, acoustic analysis, and other lab-based techniques to study how the brain maps sound to meaning and meaning to sound.
What Blumstein and other scientists believe is that the brain organizes words into networks, linked both by similarity of meaning and similarity of sound. To say "pear," a speaker will also activate other competing words like "apple" (which competes in meaning) and "bear"(which competes in sound). Despite this competition, normal speakers are able to select the correct word.
In a study published in the Journal of Cognitive Neuroscience in 2010, for example, she and her co-authors used functional magnetic resonance imaging to track neural activation patterns in the brains of 18 healthy volunteers as they spoke English words that had similar sounding "competitors" ("cape" and "gape" differ subtly in the first consonant by voicing, i.e. the timing of the onset of vocal cord vibration). Volunteers also spoke words without similar sounding competitors ("cake" has no voiced competitor in English; gake is not a word). What the researchers found is that neural activation within a network of brain regions was modulated differently when subjects said words that had competitors versus words that did not.
One way this competition-mediated difference is apparent in speech production is that words with competitors are produced differently from words that do not have competitors. For example, the voicing of the "t" in "tot" (with a voiced competitor 'dot') is produced with more voicing than the "t" in "top" (there is no 'dop' in English). Through acoustic analysis of the speech of people with aphasia, Blumstein has shown that this difference persists, suggesting that their word networks are still largely intact.
An experimental therapy
The therapy Blumstein has begun testing takes advantage of what she and colleagues have learned about these networks.
"We believe that although the network infrastructure is relatively spared in aphasia, the word representations themselves aren't as strongly activated as they are in normal subjects, leading to speech production impairments," she said. "Our goal is to strengthen these word representations. In doing so it should not only improve production of trained words, but also have a cascading effect and strengthen the representations of words that are part of that word's network."
Much like physical therapy seeks to restore movement by guiding a patient through particularly crucial motions, Blumstein's therapy is designed to restrengthen how the brain accesses its network to produce words by engaging patients in a series of carefully designed utterances.
"We hope to build up the representation of that word and at the same time influence its whole network," she said.
Overall the therapy is designed to last 10 weeks with two sessions a week. In one step of the regimen, a classic technique, a therapist will ask patients to repeat certain training words with a deliberate, melodic intonation. The next session the therapy would repeat those words without the chant-like tone.
"Having to produce words under different speaking conditions shapes and strengthens underlying word representations," said Blumstein, who is affiliated with the Brown Institute for Brain Science.
Confronting the delicate distinctions of words in the network head-on, Blumstein asks patients to say words that sound similar. "Pear" and "Bear" for example. Explicitly saying similar words, Blumstein said, requires that their differences be accentuated, thus helping strengthen the brain's ability to distinguish them.
Finally the therapy builds upon these earlier exercises by encouraging patients to repeat words they have not been practicing. A patient's ability to correctly repeat untrained words is an important test of whether the therapy can generalize to the broader networks of the training words.
In early testing with four patients, two fluent and two nonfluent, Blumstein said she has seen good results. After only two proof-of-concept sessions—one week's worth of training—three of four patients showed improved precision in producing similar sounding trained and untrained words, as measured via computer-assisted acoustic analysis. The patients also produced fewer speaking errors and had to try fewer times to say what they were supposed to.
If the therapy proves successful, Blumstein said, one effect she'll be watching for is whether it allows people with aphasia to speak more, not just more accurately. That would represent the fullest restoration of expression and language communication.
Journal reference: Journal of Cognitive Neuroscience
Provided by Brown University
- Psychologist identifies area of brain key to choosing words Dec 24, 2008 | not rated yet | 0
- New treatments may help restore speech lost to aphasia Sep 28, 2012 | not rated yet | 0
- At a loss for words Nov 21, 2011 | not rated yet | 0
- Hidden stroke impairment leaves thousands suffering in silence Oct 01, 2012 | not rated yet | 0
- Bilingualism no big deal for brain, researcher finds May 31, 2011 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Pressure-volume curve: Elastic Recoil Pressure don't make sense
21 hours ago From pressure-volume curve of the lung and chest wall (attached photo), I don't understand why would the elastic recoil pressure of the lung is...
If you became brain-dead, would you want them to pull the plug?
May 17, 2013 I'd want the rest of me to stay alive. Sure it's a lousy way to live but it beats being all-the-way dead. Maybe if I make it 20 years they'll...
MRI bill question
May 15, 2013 Dear PFers, The hospital gave us a $12k bill for one MRI (head with contrast). The people I talked to at the hospital tell me that they do not...
Ratio of Hydrogen of Oxygen in Dessicated Animal Protein
May 13, 2013 As an experiment, for the past few months I've been consuming at least one portion of Jell-O or unflavored Knox gelatin per day. I'm 64, in very...
Alcohol and acetaminophen
May 13, 2013 Edit: sorry for the typo in the title , can't edit I looked around on google quite a bit and it's very hard to find precise information on the...
Marie Curie's leukemia
May 13, 2013 Does anyone know what might be the cause of Marie Curie's cancer
- More from Physics Forums - Medical Sciences
More news stories
For combat veterans suffering from post-traumatic stress disorder, 'fear circuitry' in the brain never rests
Chronic trauma can inflict lasting damage to brain regions associated with fear and anxiety. Previous imaging studies of people with post-traumatic stress disorder, or PTSD, have shown that these brain regions can over-or ...
Neuroscience 23 hours ago | 5 / 5 (1) | 0 |
The neural machinery underlying our olfactory sense continues to be an enigma for neuroscience. A recent review in Neuron seeks to expand traditional ideas about how neurons in the olfactory bulb might encode information about ...
Neuroscience May 17, 2013 | not rated yet | 0 |
(Medical Xpress)—What if the quality of your work depends more on your focus on the piano keys or canvas or laptop than your musical or painting or computing skills? If target users can be convinced, they ...
Neuroscience May 17, 2013 | 3.7 / 5 (3) | 0 |
Neurological disorders can have a devastating impact on the lives of sufferers and their families.
Neuroscience May 17, 2013 | 5 / 5 (1) | 0 |
If you're a left-brain thinker, chances are you use your right hand to hold your cell phone up to your right ear, according to a newly published study from Henry Ford Hospital in Detroit.
Neuroscience May 16, 2013 | 2 / 5 (2) | 0 |
Regular consumption of coffee is associated with a reduced risk of primary sclerosing cholangitis (PSC), an autoimmune liver disease, Mayo Clinic research shows. The findings were being presented at the Digestive Disease ...
9 minutes ago | not rated yet | 0 |
Patients with treatment-resistant major depression saw dramatic improvement in their illness after treatment with ketamine, an anesthetic, according to the largest ketamine clinical trial to-date led by researchers from the ...
8 minutes ago | not rated yet | 0 |
An increasing number of U.S. children are experiencing gastrointestinal issues that require interventions to resolve, according to research presented at Digestive Disease Week (DDW).
14 hours ago | not rated yet | 0 |
The latest makeover to a massive psychiatric tome honored by some, reviled by others and even called the "Bible" of mental disorders is being released Saturday with a host of new changes.
12 hours ago | not rated yet | 0
Big names in medicine are set to give an upbeat assessment of the war on AIDS on Tuesday, 30 years after French researchers identified the virus that causes the disease.
22 hours ago | 5 / 5 (1) | 0
A new case of the deadly coronavirus has been detected in Saudi Arabia where 15 people have already died after contracting it, the health ministry announced on Saturday on its Internet website.
12 hours ago | not rated yet | 0