General Neuroscience

The Truth About Dyslexia: A Complete Overview

Varun Vasireddy


Introduction

 As we mature from infancy to early childhood, we develop one of the most important skills known to our species,  the ability to communicate, which begins with the capability to talk. Soon after, we begin to read and craft sentences. Oral communication has been present since the beginning of mankind. However, written language has only been present for roughly 5,000 years. Mastering the art of reading and writing is not an easy process, however some children, even with normal intelligence and motivation, find it unusually hard to read and write. Dyslexia is a common condition that affects as many as fifteen to twenty percent of all Americans [1]. This article discusses dyslexia in detail, its complications, and what a dyslexia diagnosis really means. 

 

General Overview of Dyslexia

Dyslexia, commonly classified as a learning disability, affects the ability of people to read, write, and spell. The various symptoms of dyslexia include stuttered or slow speaking, difficulty naming objects, such as when shown a picture, problems with speed while reading, and articulating words while reading. Dyslexia is a chronic disability, which is most often diagnosed in the early schooling years. Although dyslexia cannot be cured, many dyslexics can improve their fluency, the speed at which they read, and their accuracy [1]. There is no comprehensive test or set of symptoms available to identify dyslexia, which often makes it go unnoticed. Dyslexia affects children in many different ways, which makes it common for parents and teachers to assume that a child’s difficulty with reading is just associated with slow development. A dyslexia diagnosis should be made by a licensed medical professional, usually a psychologist or a neurologist [2]. 

 

Dyslexia: Inside the Brain

The act of reading involves two main ideas, or processes:the orthography of the language and deriving the phonemic structure [3]. The orthography of the language refers to being able to recognize the language’s symbols in the right order while deciphering the respective symbols into accurate sounds, is the derivation of the phonemic structure. The English language has forty-four phonemes or distinct sounds that differentiate words within a language [3]. Dyslexics have problems with these 

mechanisms, which is largely caused by issues with their visual processing. Magnocellular cells, meaning large cells, which are located throughout the visual system, are specialized to track moving stimuli and are key in concentrating on a target, such as while reading [3]. When the reader is distracted or loses concentration, the magnocellular cells send an error signal to the eyes which brings them back to focus. This feedback system is crucial to help maintain a steady focus while reading. However, this system is impaired in dyslexics, meaning that the reader cannot maintain a constant plane while reading. This is why patients will often complain that the letters are blurry, or even moving around. 

 

Anatomical Differences

Brain imaging is now a common technique used to explore the human brain in a non-invasive manner. These various techniques include MRI, fMRI, CT scans, and many others. Functional magnetic resonance imaging, more commonly known as fMRI, takes place in a large magnetic tube with powerful magnets that are used to build a detailed three-dimensional picture of the brain, like a traditional MRI. However, an fMRI also tracks the oxygen flow throughout the brain which helps neurologists identify what parts of the brain are active during a certain task. Studies using brain imaging demonstrate that certain parts of the brain are less active in dyslexic readers than in fluent readers. One of these areas is the visual word- form area (VWFA), which is located in the temporal lobe of the brain. The VWFA is responsible for recognizing letters and familiar words. This area also helps attach significance to a phrase or sentence with its connections throughout the brain [1]. Another area that shows considerably less activity in people with dyslexia is the left occipitotemporal cortex. The left occipitotemporal cortex is crucial in the recognition of letters and words by identifying their shapes. The left occipitotemporal cortex also works together with other parts of the brain to connect a number or symbol to a concept [1]. Overall, dyslexics have less brain activity in the left hemisphere of their brain, which is responsible for language processing and speech production. As a result, dyslexics often tend to rely more on their right hemisphere. 

 

Potential Causes

There is no single cause of dyslexia. However, most studies agree that dyslexia is highly influenced by genetic factors. Some studies show that sixty to seventy percent of dyslexia cases are due to genetic factors and around thirty percent of cases are due to environmental factors [5]. Environmental factors include low birth weight, lead exposure during pregnancy, and premature birth among others. Twin studies have shown that when one twin is diagnosed with the disorder, the other twin also has dyslexia about fifty-five to seventy percent of the time [1]. There have been about 40 genes that have been shown to be connected to dyslexia in various studies [6]. Almost all of the chromosomes in our body have some linkage to dyslexia. However, no single gene has been identified as the major cause of genetically inherited dyslexia. There are various labs and studies going on around the world to find the main gene involved with genetic dyslexia.

 

Potential Drug Treatments

Dyslexia does not have a permanent cure. However, most patients are able to improve their skills of reading and writing to a certain extent. There are various treatment options for dyslexia and scientists do not agree on a so-called “best treatment”. Treatment is based on a patient to patient basis because dyslexia can affect people to various degrees. There are relatively few new treatments. These treatments have been experimental and have shown significant success. However, none of these treatments or drugs have been approved for commercial and pharmaceutical use. Many studies have shown that ADHD and dyslexia are linked disorders. ADHD, which stands for Attention Deficit Hyperactivity Disorder, is another common childhood psychiatric disorder. ADHD is characterized by being distracted easily, having trouble focusing on a set goal, acting on an impulse, and sometimes having trouble sitting still. Statistics show that anywhere from fifteen to forty percent of children with dyslexia also have ADHD [7]. A drug named atomoxetine, which is normally taken by children with ADHD, has shown success in a particular study. In this study, children were split into three groups. There were children with dyslexia only, children with ADHD and dyslexia, and children with only ADHD. These three groups were randomly assigned either atomoxetine or a placebo and instructed to take the pill daily for 16 weeks [8]. The children were given a baseline reading test before administering the pills. After the completion of the 16 weeks, another reading test was given. Researchers found that children with dyslexia or both dyslexia and ADHD showed significant progress with reading as opposed to children with only ADHD, who were not affected as much [8]. Atomexetine is not yet a regularly prescribed treatment for dyslexia. This is an exciting development in the trials of a drug for dyslexia. However, there are potential drawbacks of a drug including accessibility and affordability. There is no guarantee that a potential drug would be cost effective for all, or accessible to everyone around the world in large quantities.

 

Potential Non-Drug Treatments

There has also been a non-drug treatment that has shown success in a separate study. This particular study focuses on the fact that dyslexia is a problem with the lack of coordination [9]. Researchers assigned a series of exercises focused on the cerebellum and focusing on certain eye movements. These exercises are used by astronauts because they sometimes suffer a temporary form of dyslexia while in space [9].The children were instructed to perform the exercises two times a day, one set in the morning and the other before bed [9]. The exercises included walking downstairs backward with their eyes closed, standing on a wobbly or uneven surface, and catching and throwing something from one hand to another [9]. The study was carried out for 3 years and during this period they were given reading checkpoints every 6 months and an SAT test yearly. The results of the study were astonishing. The dyslexic children caught up to the reading level of their peers in around a year and they scored better on the SATs than efficient readers. Another observation was that children who had more severe dyslexia showed the greatest improvement. This experiment proved the link of the cerebellum in processes such as reading and paying attention [9]. This non-drug treatment still has to be approved by medical professionals and tested on a more wide-scale basis before it is approved. This treatment would most likely be accessible for all. There would be no need to purchase drugs on a regular basis, which means there would be no worries of being able to afford a drug. Once a dyslexia diagnosis is made, these exercises can be performed virtually anywhere, with almost no equipment. The future of treatments for dyslexia is very bright as there are many labs, universities, and private studies trying to find a treatment for the most common learning disability in the world. There is hope that a dyslexia treatment will be found in the near future, improving the literacy rate all round the globe.  

 

Conclusion

A dyslexia diagnosis does not mean the end of the world. There has also been some research that dyslexics might be better at perceptual thinking and making advanced connections. Dyslexics have proven to have great spatial awareness, being excellent puzzle solvers, and thinking outside of the box [10]. People with dyslexia have great imaginations which help them with critical and abstract thinking. Dyslexics go on to accomplish many things in various fields including art, music, and science. Leonardo da Vinci, Hans Christian Andersen, Thomas Edison, Albert Einstein, and other Nobel Laureates and artists were also dyslexic [3]. A cure of dyslexia may be in our near future, allowing many the ability to read and write, a skill which we often take for granted.


References


  1. Society For Neuroscience. (06/06/2018). BrainFacts: A Primer On The Brain And Nervous System. Childhood Disorders. 74-75. Retrieved; 19/04/2020

  2. Marshall, Abigail. (2019). What kind of professional is qualified to diagnose dyslexia?. Davis Dyslexia Association International. https://www.dyslexia.com/question/who-can-diagnose/. Retrieved; 19/04/2020

  3. British Neuroscience Association. (2003). Neuroscience Science of the Brain: An Introduction For Young Students. Dyslexia. 25-26. Retrieved; 20/04/2020

  4. The Reading Well. (2016). Causes of Dyslexia. The Reading Well: A virtual well of dyslexia resources. https://www.dyslexia-reading-well.com/causes-of-dyslexia.html. Retrieved; 20/04/2020

  5. Dorta, Nelson. (2018)_ Is dyslexia genetic?. Understood. https://www.understood.org/en/learning-thinking-differences/child-learning-disabilities/dyslexia/is-dyslexia-genetic. Retrieved; 20/04/2020

  6. Bouchard, Ellen. (09/03/2020). Is dyslexia genetic?. The Tech Interactive. https://genetics.thetech.org/ask-a-geneticist/dyslexia-genetic. Retrieved; 20/04/2020

  7. Vann, Madeline. (28/03/2011). Is it ADHD or Dyslexia- or Both?. Everyday Health. https://www.everydayhealth.com/add-adhd/is-it-adhd-dyslexia-or-both.aspx. Retrieved; 21/04/2020

  8. Clinical Pharmacist. (20/04/2017). ADHD drug shows promise for treating dyslexia. Pharmaceutical Journal. https://www.pharmaceutical-journal.com/news-and-analysis/research-briefing/adhd-drug-shows-promise-for-treating-dyslexia/20202584.article?firstPass=false. Retrieved; 21/04/2020

  9. Hope, Jenny. (30/10/2006). Hope for millions as scientists find ‘cure’ for dyslexia. Daily Mail. https://www.dailymail.co.uk/health/article-413354/Hope-millions-scientists-cure-dyslexia.html. Retrieved; 21/04/2020

  10. Petrova, Jillian. (2020). The Many Strengths of Dyslexics. University of Michigan. http://dyslexiahelp.umich.edu/dyslexics/learn-about-dyslexia/what-is-dyslexia/the-many-strengths-of-dyslexics. Retrieved; 21/04/20

Varun Vasireddy

Varun Vasireddy


Varun Vasireddy is a rising sophomore from Saint Louis, Missouri. He is very passionate about service and neuroscience. Varun is an International HOSA Champion in the Behavioral Health Category and placed in the top 5 at the STL Brain Bee. He is the youth volunteer lead at NorthSouth Foundation and works to provide scholarships to poor children in India. Outside of the IYNA, Varun enjoys binge watching shows, reading, biking, and baking.