Dyslexia: Cognitive subtypes of dyslexia

Recent research into Dyslexia and the large range or variations in perception and experience accorded to those who have this condition.

Different theories conceptualise dyslexia as either a phonological, attentional, auditory, magnocellular, or automatisation deficit.

Such heterogeneity suggests the existence of yet unrecognised subtypes of dyslexics suffering from distinguishable deficits.

The purpose of the study was to identify cognitive subtypes of dyslexia.

Out of 642 children screened for reading ability 49 dyslexics and 48 controls were tested for phonological awareness, auditory discrimination, motion detection, visual attention, and rhythm imitation.

A combined cluster and discriminant analysis approach revealed three clusters of dyslexics with different cognitive deficits.

Compared to reading-unimpaired children;

• cluster no. 1 had worse phonological awareness; 
• cluster no. 2 had higher attentional costs; 
• cluster no. 3 performed worse in the phonological, auditory, and magno-cellular tasks. 

These results indicate that dyslexia may result from distinct cognitive impairments.

As a consequence, prevention and remediation programmes should be specifically targeted for the individual child's deficit pattern.

You can access the research paper here at PubMed.gov

Dyslexia: Is Signal Processing in the Brain the cause?

This figure compares the situation in the brain of dyslexics and the control group. 

The blue area depicts the auditory cortices and the green area represents the medial geniculate bodies.

MPI for Human Cognitive and Brain Sciences

To participate successfully in life, it is important to be able to read and write.

Nevertheless, many children and adults have difficulties in acquiring these skills and the reason is not always obvious.

They suffer from dyslexia which can have a variety of symptoms. Thanks to research carried out by Begoña Díaz and her colleagues at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, a major step forward has been made in understanding the cause of dyslexia.

The scientists have discovered an important neural mechanism underlying dyslexia and shown that many difficulties associated with dyslexia can potentially be traced back to a malfunction of the medial geniculate body in the thalamus.

The results provide an important basis for developing potential treatments. People who suffer from dyslexia have difficulties with identifying speech sounds in spoken language.

For example, while most children are able to recognise whether two words rhyme even before they go to school, dyslexic children often cannot do this until late primary school age.

Those affected suffer from dyslexia their whole lives. However, there are also always cases where people can compensate for their dyslexia.

“This suggests that dyslexia can be treated. We are therefore trying to find the neural causes of this learning disability in order to create a basis for improved treatment options,” says Díaz.

Between five and ten percent of the world’s children suffer from dyslexia, yet very little is know about its causes.

Even though those affected do not lack intelligence or schooling, they have difficulties in reading, understanding and explaining individual words or entire texts.

The researchers showed that dyslexic adults have a malfunction in a structure that transfers auditory information from the ear to the cortex is a major cause of the impairment: the medial geniculate body in the auditory thalamus does not process speech sounds correctly.

“This malfunction at a low level of language processing could percolate through the entire system. This explains why the symptoms of dyslexia are so varied,” says Díaz.

Read more at: medicalxpress.com

Auditory Hallucinations in Children Suggest Underlying Psychiatric Disorder

Children aged between 11 years to 13 years tend to hear strange voices, according to a new report.

Researchers from the Royal College of Surgeons in Ireland (RCSI) have discovered that auditory hallucinations (hearing voices) can affect up to one-in-five children between the ages of 11 to 13.

"We found that auditory hallucinations were common even in children as young as 11 years old. Auditory hallucinations can vary from hearing an isolated sentence now and then, to hearing "conversations" between two or more people lasting for a several minutes.

It may present like screaming or shouting and other times it could sound like whispers or murmurs. It varies greatly from child to child, and frequency can be once a month to once every day," said Dr Ian Kelleher, professor at the Royal College of Surgeons, in a statement.

Researchers had conducted four separate studies on 2,500 children, aged between 11 and 16 years. They found that 20 to 23 percent of younger adults, aged 11 years to 13 had experienced auditory hallucinations. Among them more than 57 percent have mental disorders.

In older adolescents (aged 13-16 years), just 7 percent reported hearing voices. However, among this category, more than 80 percent had psychiatric disorder - showing a clear association between auditory hallucinations and serious mental illness.

In several children, these experiences appear to represent a 'blip' on the radar that does not turn out to signify any underlying or undiagnosed problem.

However, for the other children, these symptoms turned out to be a warning sign of serious underlying psychiatric illness, including clinical depression and behavioural disorders, like attention deficit hyperactivity disorder.

Some older children with auditory hallucinations had two or more disorders.

It is a significant finding which can help the doctors to consider more than one diagnosis, if the child reports auditory hallucinations.

Our study suggests that hearing voices seems to be more common in children than was previously thought. In most cases these experiences resolve with time.

However in some children these experiences persist into older adolescence and this seems to be an indicator that they may have a complex mental health issue and require more in-depth assessment," said Mary Cannon, professor at the Royal College of Surgeons, in a statement.

Dyslexia: Abnormality in Auditory Processing

People with dyslexia often struggle with the ability to accurately decode and identify what they read.

Although disrupted processing of speech sounds has been implicated in the underlying pathology of dyslexia, the basis of this disruption and how it interferes with reading comprehension has not been fully explained.

Now, new research published by Cell Press in the December 22 issue of the journal Neuron finds that a specific abnormality in the processing of auditory signals accounts for the main symptoms of dyslexia.

"It is widely agreed that for a majority of dyslexic children, the main cause is related to a deficit in the processing of speech sounds," explains senior study author, Dr. Anne-Lise Giraud and Franck Ramus from the Ecole Normale Supérieure in Paris, France.

"It is also well established that there are three main symptoms of this deficit: difficulty paying attention to individual speech sounds, a limited ability to repeat a list of pseudowords or numbers, and a slow performance when asked to name a series of pictures, colors, or numbers as quickly as possible. However, the underlying basis of these symptoms has not been elucidated."

Dr. Giraud and colleagues examined whether an abnormality in the early steps of auditory processing in the brain, called "sampling," is linked with dyslexia by focusing on the idea that an anomaly in the initial processing of phonemes, the smallest units of sound that can be used to make a word, might have a direct impact on the processing of speech.

The researchers found that typical brain processing of auditory rhythms associated with phonemes was disrupted in the left auditory cortex of dyslexics and that this deficit correlated with measures of speech sound processing.

Further, dyslexics exhibited an enhanced response to high-frequency rhythms that indirectly interfered with verbal memory. It is possible that this "oversampling" might result in a distortion of the representation of speech sounds.

"Our results suggest that the left auditory cortex of dyslexic people may be less responsive to modulations at very specific frequencies that are optimal for analysis of speech sounds and overly responsive to higher frequencies, which is potentially detrimental to their verbal short-term memory abilities," concludes Dr. Giraud.

"Taken together, our data suggest that the auditory cortex of dyslexic individuals is less fine-tuned to the specific needs of speech processing."

Auditory Processing Disorder (APD)

An Auditory Processing Disorder (APD) is a disruption in the auditory nervous system that interferes with the rapid and efficient awareness, recognition, decoding and integration of acoustic signals, especially speech.

An auditory processing disorder may be considered a breakdown in a child's fine resolution abilities. By fine resolution I imply the hearing system's ability to discretely resolve the fine differences that we use to locate, separate, and distinguish sounds in the environment.

In terms of speech perception, there are many fine grained distinctions needed to successfully distinguish the many sounds that are embedded in the ongoing stream of running speech.

For instance, recognising the differences between the sounds in the words [bat] and [mommy] is not too demanding. However, distinguishing the sounds in the words [ran] and [ram] or [lift] and [list] is a more difficult task.

The latter tasks require a more efficient auditory system to rapidly identify and distinguish each pair's sounds than it does to distinguish between the sounds in the first pair. This relates to rapidly resolving the small and fine grained speech sound distinctions.

Children with APD also have problems resolving other acoustic properties, such as time variations in speech.

The two words [dime] and [time] are distinguished, predominantly, by the initiation of vocal fold vibration. The vocal folds begin to vibrate earlier when producing the [d] in dime then when producing the [t] in time.

A child who does not resolve fine time differences may have difficulty distinguishing these two words.

Timing is also important in 'juncture'. Juncture relates to the way we separate words with spaces (or time) when speaking.

Examples of varying junction include: 1) "Are you a light housekeeper?" vs. "Are you a lighthouse keeper?" 2) "Look at the snow, drift by the window." vs. "Look at the snowdrift, by the window." 3) "Look at the cargo." vs. "Look at the car go."

How do you Recognise APD?
Children who present with APD have difficulty with some or all listening activities. They have particular problems when the activities occur in less than ideal listening environments.

Hence, they may exhibit only mild problems with sound discrimination and they may make occasional errors when speaking on a one to one basis in a good (relatively quiet) environment.

They will perform worse, however, when there is competing background noise or speech, when speakers talk rapidly, when they are not devoting their complete attention to the listening task, when the discussion topic is unfamiliar to them, or when they have to perform or remember several verbal tasks in a row.

In addition, they often have weak phonemic systems (speech sound memories used in phonics, reading, and spelling). They also often appear as though they do not hear well. It is common for children with APD to say, "what?" or "huh?". They are not always intimately in touch with the sounds in the environment, hence they do not always grasp exactly what has been said.

Dyslexic Advantage - Memory and Dyslexia

Dyslexic Advantage - Memory and Dyslexia

A recent study from Norway shows what people with dyslexia have known a long time...that working memory is affected in dyslexia. In the picture below, control subjects trying to keep letter sounds in mind vs. subjects with dyslexia.

One of the most common mistakes we see in educators approaching the subject of dyslexia is to think the only issues is phonological awareness. Some students have both, but for most, the memory is a problem as big or even bigger than distinguishing sounds.

Problems from Working Memory Challenges

•Hard time following conversations in background noise
•Trouble learning a foreign language
•Problems following a foreign language speaker
•Dismissed as 'inattentive ADD'
•Have to write auditory information down to remember

The importance of realising that working memory issues are affecting dyslexia is that working memory seems to be highly trainable.

Some of greatest leaps in IQ's we've seen over the years have been in students who acquire more strategies to organise their ideas and who work hard at tasks to train up their working memory.

It doesn't always have to be expensive software programs to train up working memory - it can involve persisting at difficult working memory tasks like mathematics, writing, or acquiring an 'easier' foreign language.

Working memory problems also highlight the need to employ multisensory approach to learning sounds. Making images, humorous, or other more interesting information to forgettable facts or sounds can help the data to 'stick'.

Therapeutic Games and Music for Auditory Hypersensitive and ADHD Children

Therapeutic games and music for auditory hypersensitive, autistic, downs syndrome, pdd and add children.

Lecture delivered to the World Organization Meeting of the
Institutes for the Achievement of Human Potential. May 1994, by
William P. Mueller Vice Chairman of the Board of Directors

Transient Electronic Auditory Stimulation

The Institutes have known for forty years that certain brain-injuries cause hyperactive auditory sensitivity.

In the past twenty years others have also begun to study this problem. I first beame aware of that condition when I met David, an eight year old brain-injured child at The Institutes who had this problem.

He screamed at the slightest noise. In fact, he screamed eight hours a day. His parents whispered all day to keep from setting him off.

When they arrived at The Institutes he was given the auditory stimulation program as part of his overall program. His parents were instructed to bang pots and pans randomly around the house!

David's mother told me she laughed all the way home after that initial visit. However, they did The Institute's auditory stimulation program and within two weeks David was no longer hypersensitive to sound.

Dyslexia: Music can Help Reading Skills

The part of the brain that interprets sound, known as the auditory cortex, responds faster in people with musical training and is better primed to pick out subtle patterns from the huge volumes of information that flood into the brain from our senses.

Neuroscientists have found that musicians benefit from heightened brain activity that allows them to process information from their eyes and ears more efficiently than non-musicians.

They found that the part of the brain that interprets sound, known as the auditory cortex, responds faster in people with musical training and is better primed to pick out subtle patterns from the huge volumes of information that flood into the brain from our senses.

Professor Nina Kraus, a neuroscientist and amateur musician at Northwestern University in Evanston, Illinois, has also found that this part of the brain plays a crucial role in reading.

Speaking at the annual meeting of the American Association for the Advancement of Science in San Diego on Saturday, she called for music to become a more important part of school syllabuses to help children develop better reading and language skills.

She said: "There is a strong argument for more musical education, especially in schools.

"Our eyes and ears take in millions of bits of information every second and it is not possible for the brain to process all of that, so the sensory systems in our brains are primed to tune into regularities or patterns in the signals it receives.

"People who are musically trained are better at picking up these patterns because they learn to recognise notes and pitches within melodies and harmonies.

"The better you are at picking up these patterns in music, the better reader you are. This makes sense as letters and words on a page are really just patterns."

Professor Kraus and her team have used a method known as electroencephalography, which measures electrical activity in the brain, to examine how musicians and non-musicians brains respond to different stimulus.

Mindroom - Learning Difficulties - Dyslexia Information

Mindroom - Learning Difficulties - Dyslexia Information

DYSLEXIA
Dyslexia is characterised by specific problems in learning to read and write.
It is best described as a combination of abilities and difficulties that affect the learning process in one or more of reading, spelling, writing.

Dyscalcula - problems with mathematics

Dysgraphia - a learning disability resulting from the difficulty in expressing thoughts in writing. It generally refers to extremely poor handwriting.

There are three types of dyslexia– motor, visual, auditory

Associated features

• Poor working memory – especially for sequenced, auditory – linguistic material
• Difficulties with phonology – the sounds in words.
• Problems in distinguishing left/right
• Poor sense of direction
• Difficulties with time and tense
• Visual and auditory perceptual difficulties
• Unexpectedly poor reading in relation to general ability
• Spelling problems
• Difficulty remembering telephone numbers and appointments
• Bad handwriting
• Difficulty learning things by rote e.g. months of the year
• Poor concentration

Click here for further recommended reading on Dyslexia

Education: Learning styles debunked

The wide appeal of the idea that some students will learn better when material is presented visually and that others will learn better when the material is presented verbally, or even in some other way, is evident in the vast number of learning-style tests and teaching guides available for purchase and used in schools.

But does scientific research really support the existence of different learning styles, or the hypothesis that people learn better when taught in a way that matches their own unique style?

Unfortunately, the answer is no, according to a major new report published this month in Psychological Science in the Public Interest, a journal of the Association for Psychological Science.

The report, authored by a team of eminent researchers in the psychology of learning -- Hal Pashler (University of San Diego), Mark McDaniel (Washington University in St. Louis), Doug Rohrer (University of South Florida), and Robert Bjork (University of California, Los Angeles) -- reviews the existing literature on learning styles and finds that although numerous studies have purported to show the existence of different kinds of learners (such as "auditory learners" and "visual learners"), those studies have not used the type of randomized research designs that would make their findings credible.

Nearly all of the studies that purport to provide evidence for learning styles fail to satisfy key criteria for scientific validity. Any experiment designed to test the learning-styles hypothesis would need to classify learners into categories and then randomly assign the learners to use one of several different learning methods, and the participants would need to take the same test at the end of the experiment.

If there is truth to the idea that learning styles and teaching styles should mesh, then learners with a given style, say visual-spatial, should learn better with instruction that meshes with that style. The authors found that of the very large number of studies claiming to support the learning-styles hypothesis, very few used this type of research design. Of those that did, some provided evidence flatly contradictory to this meshing hypothesis, and the few findings in line with the meshing idea did not assess popular learning-style schemes.

No less than 71 different models of learning styles have been proposed over the years. Most have no doubt been created with students' best interests in mind, and to create more suitable environments for learning. But psychological research has not found that people learn differently, at least not in the ways learning-styles proponents claim. Given the lack of scientific evidence, the authors argue that the currently widespread use of learning-style tests and teaching tools is a wasteful use of limited educational resources.

Education: Learning styles debunked

Dyslexia Untied - Phonological Dyslexia

Phonological Dyslexia
(Also known as Dysphonetic, Auditory or dysphonesia dyslexia) This kind of dyslexia is the most common and the person has difficulty in identifying phenomes i.e the sounds within words, and will have difficulty matching letters to sounds.

When trying to read they will make wild guesses at words and will struggle with nonsense words or fictional words that have been constructed from Proper names, Mnemonics, etc.

Greater difficulty will occur when spelling words and they will try to make sense of the illogical chaos and lack of comprehension they are experiencing. Their attempts to spell will include impossible letter combinations e.g. 'sfr'

Most tests for Dyslexia will include the requirement to read nonsense words e.g. 'sluft' and 'prenck'. This is to force the subject to read and sound out the letter combination as a word, revealing an underlying comprehension with letters, words and their construction. Also, it is thought to prevent the subject from simply guessing words they have heard rather than one's they have read.

This test and exercise is meant to determine whether a subject has a Phonological Dyslexia.