What is Dyslexia?

Research Definition of Dyslexia

According to The National Institutes of Health, the research definition of dyslexia is:

  • A specific learning disability that is neurological in origin.
  • It is characterized by difficulties with accurate and/or fluent word recognition, and by poor spelling and decoding abilities.
    • These difficulties typically result from a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction.
  • Secondary consequences may include problems in reading comprehension and reduced reading experience that can impede growth of vocabulary and background knowledge.

Strength-Based Definition of Dyslexia

Although I agree with The National Institutes of Health’s definition, I personally like to focus on strengths instead of weaknesses, so I prefer Cheri Rae’s strength-based definition. She is the mother of a dyslexic and author of the book DyslexiaLand.

In her book, she defines dyslexia as a specific learning ability, neuro-biological in origin, typically characterized by strengths including creative expression, athletic performance, and scientific discovery.

The individual with dyslexia often exhibits strength in thinking outside the box, making unexpected connections, and from an intuitive sense about the world.

Secondary strengths include a different learning style that may be auditory or kinesthetic, the ability to demonstrate knowledge in ways other than the written word, and an uncanny sense of entrepreneurialism that may lead to great innovations and financial success.


Dyslexia is a hereditary condition. It runs in families; if someone has dyslexia, they were born with it and will have it throughout life. With all the advancements within medicine, researchers have been able to locate a chromosome responsible for dyslexia.

This was released by Yale School of Medicine several years ago:

Pediatric researchers at Yale School of Medicine have identified a gene on human chromosome 6 called DCDC2, which is linked to dyslexia, a reading disability affecting millions of children and adults. The researchers also found that a genetic alteration in DCDC2 leads to a disruption in the formation of brain circuits that make it possible to read. This genetic alteration is transmitted within families.

Not only have researchers found a chromosomal link to dyslexia, but due to the abilities functional MRI and Positron Emission Tomography (PET) units possess; they have also been able to discover that a dyslexic brain processes written information a lot differently than a non-dyslexic brain.

These scans are of a non-dyslexic and dyslexic brain while the individuals were reading a text passage. The images clearly show how the brain activity is very different within these two brains while they perform the exact same task. There is more activity going on in the non-dyslexic brain and within the left hemisphere, which is known as the language center of the brain.

Larger Brains

Researchers have known for over fifty years that dyslexic brains are larger than non-dyslexic brains.

Before the development of brain imaging, researchers relied on brain autopsies of deceased dyslexics for their studies. These autopsies revealed the same information as our modern technology does today…dyslexic brains have the same sized left hemisphere as non-dyslexics, but their right hemisphere is 10% larger than non-dyslexic brains.

The right hemisphere of the brain is known as the creative side. It is primarily responsible for creativity, imagination, and musical awareness. This side “thinks” holistically and in pictures rather than words. This larger, more dominant hemisphere is the reason why dyslexics are known to have strengths relating to creativity.

The left hemisphere of the brain is known as the language center side of the brain. Its primary function is to process language both written and spoken. This side “thinks” methodically. It has been proven that the left hemispheres of dyslexic brains are not damaged in any way. The reason dyslexics struggle so much with processing language is due to the right hemisphere being dominant.

In a non-dyslexic, left dominant brain, the language comes into the brain and goes to the left side to be processed like it was intended to. In a right dominant brain, the language comes in and goes to the right side and the right side doesn’t recognize it so it sends it to the left side to be processed. This process takes time and the information can sometimes get lost in transit. This is the reason why it can take dyslexics longer to process language information.


Dyslexia is the most common learning disability and is the most common reason for reading difficulties.

It is also one of the most researched and documented conditions that will impact children.

There is over 35 years of independent, scientific, replicated, published research that exists on dyslexia. Much of this research was conducted through the National Institutes of Health, funded by taxpayer dollars.

It affects 20% of the United States’ population, according to Yale University, who has led the nation in dyslexia research for years, and The National Institutes of Health researchers. This means 1 out of 5 people struggle with this often unidentified disability.

Dyslexia affects just as many girls as boys. A study published in 1990, in the Journal of the American Medical Association, proved this to be true. However, boys are sent for testing more often than girls. This is due to the fact that boys typically react differently to their reading and spelling challenges. Girls tend to get quiet and embarrassed by their academic struggles, while boys tend to act out and this acting out seems to get the attention of their parents and/or teachers more often.

40% of dyslexics have Attention Deficit Disorder, with or without hyperactivity, in addition to dyslexia. Many children get diagnosed with ADD, yet still struggle with reading and spelling once methods or treatments are put in place to help the ADD. This is because only the behavioral aspect of the ADD has been addressed and not the dyslexia.

More Specifics

Dyslexia crosses racial, ethnic, and socioeconomic lines.

Dyslexia is not caused from a vision problem and dyslexics do not see words, letters, or numbers backwards. They will sometimes reverse letters and/or numbers and this is due to directionality issues, not a vision problem. This is why vision therapy does NOT work for people with dyslexia.

Professionals with in-depth training can accurately identify dyslexia in a child as early as 5 years old.

Dyslexics have a lack of phonemic awareness; the ability to recognize individual sounds in words. This causes great difficulty when they try to decode words, which is the ability to match letters to sounds. Because of this, they read words inaccurately and without fluency. This will not change unless they are given the proper help. And proper help is NOT reading more. If this skill is lacking, then reading 20, 30, or 200 minutes a day will not improve their reading skills.

Their inability to read accurately and fluently affects their reading comprehension. It is very hard to understand something written if you are pronouncing the words incorrectly. However, a dyslexic can comprehend something if it is read to them.

Dyslexia is on a spectrum. It comes in different degrees ranging from mild to profound. This is the reason why no two dyslexics will have the exact same symptoms.

Dyslexia can be remediated with proper instruction and accommodations. Click here to learn more.

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