Hearing loss may change brain structure

"In the case of tinnitus, surprisingly, there were few changes to brain structure despite changes to function, suggesting that when sensory deprivation is accompanied by self-generated noise, it may be better at preserving neural tissue," says Fatima Husain.

Researchers used two different imaging modalities in studies of people with hearing loss, normal hearing, and those with hearing loss and tinnitus (ringing in the ears).

People in the hearing loss group showed structural changes in their brains.

“This suggests that functional changes due to sensory deprivation may result in long-term structural changes,” says Fatima Husain, a Beckman Institute faculty member at the University of Illinois.

The goal of the study was to investigate structural gray and white matter changes related to tinnitus and hearing loss and try to dissociate them from changes due only to hearing loss. (Credit: Fatima Husain)

“However, in the case of tinnitus, surprisingly, there were few changes to brain structure despite changes to function, suggesting that when sensory deprivation is accompanied by self-generated noise, it may be better at preserving neural tissue.”

Husain and her collaborators on the study measured neuroanatomical changes in gray and white matter in the brains of participants with only bilateral hearing loss (HL), participants who had HL and tinnitus (TIN), and a control group with normal hearing (NH) without tinnitus.

Their study, reported in the journal Brain Research, looked at neuroanatomical alterations associated with hearing loss and tinnitus.

Read the original study DOI: 10.1016/j.brainres.2010.10.095

The researchers used structural magnetic resonance imaging (MRI) scans and voxel-based morphometry (VBM) to examine changes in gray matter, and diffusion tensor imaging (DTI), to identify changes in white matter tract orientation.

While tinnitus is often accompanied by hearing loss, not everyone with hearing loss experiences tinnitus.

The goal of the study was to investigate structural gray and white matter changes related to tinnitus and hearing loss and try to dissociate them from changes due only to hearing loss.

“We observed that the HL group had the most profound changes in both white and gray matter relative to the other groups,” Husain says. The gray matter decreases seen in the HL group relative to the NH group were in the anterior cingulate, putamen, and middle frontal gyrus.

Two of these regions, the anterior cingulate and frontal cortex, were “also implicated in our companion study that studied functional response of the brain in the same group of subjects and points to involvement of the attention processing network.”

By dissociating the effect of tinnitus from hearing loss, the researchers concluded that “hearing loss rather than tinnitus had the greatest influence on gray and white matter alterations.”

Husain directs the Auditory Cognitive Neuroscience Lab in the Department of Speech and Hearing Science.

More news from the University of Illinois: http://www.beckman.illinois.edu/index.aspx

Williams Syndrome: PET Brain Scans Provide insight

A peek inside the minds of hypersocial people with Williams syndrome has revealed how the genetic disorder affects the brain.

People with Williams syndrome are known for their friendliness, although this tends to be coupled with heightened anxieties.

You can contact the UK Williams Syndrome association, here

Mbemba Jabbi at the National Institutes of Health in Bethesda, Maryland, and colleagues studied MRI scans of 14 people with the syndrome. They found that the insula, a brain region involved in emotion, was smaller than in 23 people without the syndrome.

When Jabbi's team used PET scans to examine the insula in more detail, though, they found that one area of the right insula was larger in people with Williams syndrome. Those with more extreme personality differences had more grey matter here.

The findings could help predict how social symptoms of the syndrome might develop, says Debbie Riby at Newcastle University, UK.

However, the people who participated in the study have a normal IQ, which is typical of only a small percentage of those with Williams syndrome, she says.

Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1114774109

A tractography study in dyslexia: neuroanatomic correlates of orthographic, phonological and speech processing

Diffusion tensor imaging tractography is a structural magnetic resonance imaging technique allowing reconstruction and assessment of the integrity of three dimensional white matter tracts, as indexed by their fractional anisotropy.

It is assumed that the left arcuate fasciculus plays a crucial role for reading development, as it connects two regions of the reading network, the left temporoparietal region and the left inferior frontal gyrus, for which atypical functional activation and lower fractional anisotropy values have been reported in dyslexic readers.

In addition, we explored the potential role of the left inferior frontal-occipital fasciculus, which might connect a third region of the reading network, the left ventral occipitotemporal region with the left inferior frontal gyrus.

In the present study, 20 adults with dyslexia and 20 typical reading adults were scanned using diffusion tensor imaging, and the bilateral arcuate fasciculus and the left inferior fronto-occipital fasciculus were delineated.

Group comparisons show a significantly reduced fractional anisotropy in the left arcuate fasciculus of adults with dyslexia, in particular in the segment that directly connects posterior temporal and frontal areas.

This fractional anisotropy reduction might reflect a lower degree of myelination in the dyslexic sample, as it co-occurred with a group difference in radial diffusivity.

In contrast, no significant group differences in fractional anisotropy were found in the right arcuate fasciculus or in the left inferior fronto-occipital fasciculus.

Correlational analyses (controlled for reading status) demonstrated a specific relation between performance on phoneme awareness and speech perception and the integrity of left arcuate fasciculus as indexed by fractional anisotropy, and between orthographic processing and fractional anisotropy values in left inferior fronto-occipital fasciculus.

The present study reveals structural anomalies in the left arcuate fasciculus in adults with dyslexia. This finding corroborates current hypotheses of dyslexia as a disorder of network connections.

In addition, our study demonstrates a correlational double dissociation, which might reflect neuro-anatomical correlates of the dual route reading model: the left arcuate fasciculus seems to sustain the dorsal phonological route underlying grapheme–phoneme decoding, while the left inferior fronto-occipital fasciculus seems to sustain the ventral orthographic route underlying reading by direct word access.

Access the Full Scientific Paper here at BRAIN: A journal of Neurology - A tractography study in dyslexia: neuroanatomic correlates of orthographic, phonological and speech processing

Dyslexia: MRI Brain Scans Spot Early Signs

Instead of waiting for a child to experience reading delays, scientists now say they can identify the reading problem even before children start school, long before they become labeled as poor students and begin to lose confidence in themselves.

Although typically diagnosed during the second or third grade of school - around age 7 or 8 - a team from Children's Hospital Boston said they could see signs of the disease on brain scans in children as early as 4 and 5, a time when studies show children are best able to respond to interventions.

"We call it the dyslexia paradox," said Nadine Gaab of the Laboratories of Cognitive Neuroscience at Children's, whose study was published in Proceedings of the National Academy of Sciences.

Gaab said most children are not diagnosed until third grade, but interventions work best in younger children, hopefully before they begin to learn to read.

"Often, by the time they get a diagnosis, they usually have experienced three years of peers telling them they are stupid, parents telling them they are lazy.

We know they have reduced self esteem. They are really struggling," Gaab said in a telephone interview.

Her study builds on an emerging understanding of dyslexia as a problem with recognizing and manipulating the individual sounds that form language, which is known as phonological processing.
In order to read, children must map the sounds of spoken language onto specific letters that make up words. Children with dyslexia struggle with this mapping process.

"The beauty is spoken language can present before written language so people can look for symptoms," said Dr. Sally Shaywitz, a director of the Center for Dyslexia and Creativity at Yale University.

Signs of early dyslexia might include difficulty with rhyming, mispronouncing words or confusing similar-sounding words.

"Those are all very early symptoms," Shaywitz said.

Dyslexia affects roughly 5 percent to 17 percent of all children and up to 1 in 2 children with a family history of the disorder will struggle with reading, have poor spelling and experience difficulty decoding words.

In her study, Gaab and colleagues scanned the brains of 36 preschool children while they did a number of tasks, such as trying to decide if two words start with the same sound.

They found that during these tasks, children who had a family history of dyslexia had less brain activity in certain regions of the brain than did children of similar ages, intelligence and socioeconomic status.

Older children and adults with dyslexia have dysfunction in these same areas of the brain, which include the junctions between the occipital and temporal lobes and the temporal and parietal lobes in the back of the brain.

Gaab said the study shows that when children predisposed to dyslexia did these tasks, their brains did not use the area typically used for processing this information. This problem occurred even before the children started learning to read.

"The important point of this paper is it shows the need to look for signs of dyslexia earlier," said April Benasich, director of the Carter Center for Neurocognitive Research at Rutgers, the State University of New Jersey, who was not part of the study.

Benasich studies language processing in even younger children - babies who have a family history of learning disorders.

"There is evidence to suggest that what is thought to be reading failure is there before the kids fail," she said.

Gaab said her study is too small to form the basis of any test for dyslexia but her team has just won a grant from the National Institutes of Health to do a larger study.

Ultimately, she hopes parents will be able to go to their pediatrician and ask for their child to be assessed.

"Families often know that their child has dyslexia as early as kindergarten, but they can't get interventions at their schools," she said in a statement.

"If we can show that we can identify these kids early, schools may be encouraged to develop programs," she said.

Low birthweight Infants at risk from Autism (5x)

Autism researchers at the University of Pennsylvania School of Nursing have found a link between low birthweight and children diagnosed with autism, reporting premature infants are five times more likely to have autism than children born at normal weight.

The children, some born as small as about a pound, were followed for 21 years making this study, published in the prestigious journal Paediatrics, one of the most remarkable of its kind.

The infants were born between September 1984 through July 1987 in Middlesex, Monmouth, and Ocean counties in New Jersey at birthweights from 500 to 2000 grams or a maximum of about 4.4 pounds.

“As survival of the smallest and most immature babies improves, impaired survivors represent an increasing public health challenge,” wrote lead authorJennifer Pinto-Martin, MPH, PhD, director of the Center for Autism and Developmental Disabilities Research and Epidemiology (CADDRE) at Penn Nursing.

“Emerging studies suggest that low birthweight may be a risk factor for autism spectrum disorders.”

Links between low birthweight and a range of motor and cognitive problems have been well established for some time, but this is the first study that establishes that these children are also at increased risk for autism spectrum disorders (ASD).

“Cognitive problems in these children may mask underlying autism,” said Dr. Pinto-Martin. “If there is suspicion of autism or a positive screening test for ASD, parents should seek an evaluation for an ASD.

Early intervention improves long-term outcome and can help these children both at school and at home.”

In future studies, Penn researchers will investigate possible links between brain hemorrhage, a complication of premature birth, and autism by examining brain ultrasounds taken of these children as newborns.

The researchers, including a team at The Children’s Hospital of Philadelphia, followed 862 children from birth to young adulthood finding that five percent (5%) of the children were diagnosed with autism, compared to one percent (1%) of the general population in what researchers called “the first study to have estimated the prevalence of ASD . . . using research validated diagnostic instruments.”

The $3 million study was funded by the National Institute of Mental Health.(NIMH)

ADHD: Brain scans reveal drugs' effects on attention

Scientists have developed a way to use PET scans to test if drugs are helping mice that have been genetically engineered to have a form of attention deficit.

In the brain of the altered mouse (right), low dopamine levels result in a brighter image. 

(Credit: David Gutmann, MD, PhD)

Scientists have developed a way to evaluate new treatments for some forms of attention deficit disorder.

Working in mice, researchers at Washington University School of Medicine in St. Louis showed that they can use brain scans to quickly test whether drugs increase levels of a brain chemical known as dopamine.

In a study published last year, the same group found that raising dopamine levels in mice alleviates attention deficits caused by neurofibromatosis type 1 (NF1), a condition that affects more than 100,000 people in the United States. Approximately 60 percent to 80 percent of children with NF1 have some type of attention deficit problem.

"Many kids with NF1 really struggle in school, and finding ways to help alleviate attention problems is a high priority," says David H. Gutmann, MD, PhD, the Donald O. Schnuck Family Professor of Neurology.

"The technique we've refined may make it possible to match specific treatments to the patients with NF1 and attention deficit who are most likely to benefit from those treatments."

The results appear online in Experimental Neurology.

Symptoms of NF1-related attention deficits are similar to those that affect children in the general population. But it's unclear whether the brain changes that underlie these problems in children with NF1 are similar to the brain changes that cause attention deficits in the general population.

"This mouse model may not be a perfect model for all forms of attention deficit, but it is a terrific model for one type of attention system dysfunction," Gutmann says. "Greater understanding of what goes wrong in some children with NF1 could lead to new insights into a broader variety of attention problems."

Gutmann is director of the Washington University Neurofibromatosis (NF) Center, a national referral center for patients with all forms of neurofibromatosis. The center is active in basic science research and clinical trials, with the goal of developing innovative new approaches for treating patients with NF.

Gutmann and his colleagues have developed genetically engineered mice that develop NF1-related attention problems and brain tumours.

Last year, Gutmann showed that one of these lines of mice had lower levels of dopamine in part of the brain. Following treatment with the drug Ritalin, both the brain dopamine levels and the attention deficits in these mice were restored to normal.

"Prior to our study, there was no molecular basis for using Ritalin to treat children with NF1 and attention deficits, so its use depended on the pediatrician's practice, the severity of the attention deficit and how comfortable the parents were with the use of medication," Gutmann says.

"In general, only the most severely affected kids are being treated, but that may change in the future."

Read more at Science Daily

Brain Training using MRI Scans: See yourself Think

As humans face increasing distractions in their personal and professional lives, University of British Columbia researchers have discovered that people can gain greater control over their thoughts with real-time brain feedback.

The study is the world's first investigation of how real-time functional Magnetic Resonance Imaging (fMRI) feedback from the brain region responsible for higher-order thoughts, including introspection, affects our ability to control these thoughts. The researchers find that real-time brain feedback significantly improves people's ability to control their thoughts and effectively 'train their brains.'

"Just like athletes in training benefit from a coach's guidance, feedback from our brain can help us to be more aware of our thoughts," says co-author Prof. Kalina Christoff, UBC Dept. of Psychology. "Our findings suggest that the ability to control our thinking improves when we know how the corresponding area in our brain is behaving."

People control thoughts better when they see their brain activity

Dyslexia: MRI Scan 'predicts when dyslexic will read'

The brain disorder makes it difficult for even very bright children to learn how to read and can be a lifelong source of frustration.

But according to research published in the Proceedings of the National Academy of Science (PNAS), brain scans can predict the improvement of teenagers' reading skills, with up to 90 per cent accuracy.

"This study takes an important step toward realising the potential benefits of combining neuroscience and education research by showing how brain scanning measures are sensitive to individual differences that predict educationally relevant outcomes," said Bruce McCandliss, one of the lead authors of the study and a professor at Vanderbilt University.

The research found brain scan results to be significantly more accurate in predicting how well a dyslexic child ultimately reads than standardised reading tests or the child's behaviour.

"This approach opens up a new vantage point on the question of how children with dyslexia differ from one another in ways that translate into meaningful differences two to three years down the line," Prof McCandliss said.

He said the research raises the prospect of a future test that could help match dyslexic students with the most effective treatments.

"Such insights may be crucial for new educational research on how to best meet the individual needs of struggling readers," he said.

The research was primarily conducted by experts at the Stanford University School of Medicine, with help from researchers at the Massachusetts Institute of Technology, the University of Jyvaskyla in Finland. and the University of York in the United Kingdom.

Pronouns Aid Brain Function

New research suggests that pronouns may play a far greater role than simply replacing a proper name in a sentence. A University of South Carolina study suggests that pronouns help keep the brain’s complex circuitry and limited memory system from being overloaded.

Using fMRI (functional magnetic resonance imaging), psychology researcher Dr. Amit Almor and colleagues studied the brain activity of 21 adults, ages 19 - 34, who were asked to read sequences of sentences to compare the brain’s response to pronouns versus proper names.

Almor’s findings are featured in the cover article in the current issue of the NeuroReport, a scientific journal.

“The brain lit up with activity when proper names were used, including areas that are not associated with language,” Almor said. “We saw considerable activity in areas of the parietal lobe that involve spatial processing that was absent when pronouns were used.”

Almor is the first researcher to use brain imaging to explore the neurological underpinnings of humans’ preference for pronouns. He conducted his research at the university’s McCausland Center for Brain Imaging.

The brain responds to proper names by creating a representation of the person in the mind, drawing from various parts of the brain to construct complex visual, sound and other information associated with that person. Every time the name is repeated, the brain responds by activating a process that creates a new representation of the person.

The brain initially holds each created representation in memory. The integration of these multiple representations requires effort that can disrupt the brain’s ongoing processing of what it hears during spoken conversation.

Pronouns, while faulty for their potential ambiguity, don’t cause the same disruptions in the brain that proper names do when used in the right context. In fact, they allow the brain to move easily from one thought or sentence to another. This seamless transition allows a person to digest more fully the meaning or intent of the thought being conveyed without the neural circuitry interference that proper names cause, said Almor.

“We are at the mercy of our memory system, which is limited,” Almor said. “The more items or representations we hold, the more effort we need to spend so as not to lose information. Pronouns let us avoid that juggle in our brains. I expected to find activity in classic language areas of the brain. I was surprised to see activity in the spatial areas, but it makes perfect sense.”

To read the full article click here on the link