Brain Stimulation Improves Reading Accuracy, Phonemic Processing in Dyslexia
Thu, April 22, 2021

Brain Stimulation Improves Reading Accuracy, Phonemic Processing in Dyslexia


Dyslexia is a learning disability in reading and not a problem with intelligence. People with dyslexia have difficulty reading without mistakes and at a good pace because they have trouble connecting the letters that they see and the sounds they make. They may also have a hard time with writing, spelling, and reading comprehension. Treatment usually involves the use of specific educational techniques and approaches, such as touch, hearing, and vision to improve reading skills.

Phonemic processing and oscillatory function

A new study published in PLOS Biology also suggests that brain stimulation improves reading accuracy and phonemic processing of adults with dyslexia. Authors Silvia Marchesotti from the Department of Neuroscience, University of Geneva and the team wrote that the phonological (sounds in spoken words and the ability to manipulate sounds) deficit is linked with the altered low-gamma oscillatory function in the left auditory cortex of the brain. It is a side of the brain that has been shown to be more sensitive to sequential differences in sound, like in speech. Yet, the causal connection between phonemic processing and oscillatory function has not yet been established in previous studies.

tACS effect on phonological processing

To solve this question, the team applied 20 minutes of transcranial alternating current stimulation (tACS) over the left auditory cortex in 15 fluent readers and 15 adults with dyslexia. They found that the intervention improved the reading accuracy and phonological processing of those in the dyslexia group, particularly when they used 30Hz but not 60Hz. They found that the beneficial effect of phonological processing was most noticeable among adults with poor reading skills but it created a slightly disruptive effect in “very good readers.” This result, the team added, could be related to past observations that very fast readers may have developed neural reading techniques that largely skip the phonological processing as a 30Hz tACS is shown to negatively interfere with their reading.



By reinstating the 30Hz activity, it made an immediate effect on the phonological deficit of the dyslexia group and improved both their text-reading accuracy and pseudoword reading by 15%. Yet, a single 20Hz tACS exposure was not enough to induce a long-lasting enhancement of their low-gamma. According to Healthline, which is not involved in the study, our brain is a busy place. Brain waves are evidence of the electrical activity that is produced by our brain. A wave-like pattern is created when a group of neurons sends a burst of electrical pulses to another group of neurons.

These brain waves are measured in speed cycles for every second, describes as Hertz or Hz. The waves may be very fast or very slow, depending on how alert or awake the person is. They do and can change based on how a person is feeling and what they are doing. Gamma waves are known as the fastest brain waves. They can be difficult to measure accurately.

UK-based dyslexia training provider Dyslexia Action shares that the number of people with dyslexia in the UK alone is around 10% with 4% at the severe end of the dyslexia range. Such percentage equates to around 7.3 million people.

In the US, there are more than 100 private schools for dyslexic students. In the UK, there are around 25 and in Canada 6. Most of these schools for dyslexia students prepare a detailed plan for every student but not all of them are dedicated to dyslexic students alone. They may serve students with other kinds of learning disabilities, such as Asperger’s, ADD or ADHD, and other autism spectrum disorders.



Signs and symptoms of dyslexia

The common signs and symptoms of dyslexia are memory difficulties, organizational difficulties, reading difficulties, writing difficulties, and time management difficulties. Auditory and visual processing difficulties are also experienced by some people diagnosed with dyslexia. Their challenges are highlighted around verbal memory, verbal processing speed, and phonological awareness.

With motivation and appropriate teaching methods, people with dyslexia can successfully learn anything. They may even excel at connecting ideas, 3D mapping, thinking out of the box, and seeing the big picture. These are considered to be compensatory skills instead of natural gifts. People with dyslexia also usually find success in the fields of drama, math, electronics, sales, sports, physics, music, mechanics, design, computer science, and art.

As for Dr. Marchesotti and the team’s study, they note that their findings may pave the way to non-invasive therapeutic interventions aimed to improve phonological processing and normalize oscillatory function in the auditory cortex in individuals with dyslexia. Dr. Marchesotti also told Medical Xpress that they are planning to investigate whether the normalizing oscillatory function in very young kids could have a long-lasting effect on the organization of their reading system. They will likewise explore the less invasive means of correcting the oscillatory activity using neurofeedback training.

The experimental paradigm conducted by the team was approved by the local Ethics Committee. Their findings have been registered retrospectively in a publicly accessible clinical trial registry that is approved by the World Health Organization.



Struggling readers

In the world’s largest annual study of the reading habits that comprise 9.9 million students in more than 30,000 schools across the United States, K-12 educational software provider Renaissance shows that 15 minutes of reading per day accelerated the students’ reading gains.

On average, Grade 3 students who failed to meet the grade-level benchmarks by the end of the year had 14.6 minutes of engaged reading time per day. On the other hand, those who met the college- and career-readiness benchmarks for their grade read for 20.0 minutes, which is a difference of less than 6 minutes of daily reading time. These students likewise had 11% higher comprehension and read 100, 448 more words than their Grade 3 peers who did not meet the benchmarks. The statistics show that a few additional minutes of daily reading practice for struggling readers can help them turn into successful readers. Yet, about 54% of the students in the study do not get enough daily reading practice and only 18% of them read for 30 minutes or more every day.

Everyone develops and learns at their own pace and reading is the same as other skill-building. Dyslexia is not something one grows out of but with the right support, it is possible to maximize their learning.