Written by: Roselyn Mathew / Medical Rehabilitation / September 21, 2022 / 7 minutes read

Dyslexia is described as a difficulty to read words and numbers and associate them with the speech sounds. The ability to read alphabet sequences to read a word is called phoneme grapheme correspondence.  For example, the alphabet ‘B’, ‘E’ and ‘T’ is pronounced in the same way in almost all the words. A person who is reading the word ‘Bet’ for the first time would apply the sound rules and would be able to read or write the word ‘Bet’ correctly even though they are reading or hearing it for the first time. Here, they are using the phoneme-grapheme correspondence. This skill is picked up by children when they learn new sounds in a language. For a person with dyslexia, the phoneme-grapheme correspondence is usually affected. This is one of the reasons that results in difficulties in reading and writing.

Sometimes, errors can happen where the sequence is affected. For example, while reading or writing numbers, person might read or write the number 121 as one hundred and twelve or two hundred and eleven. There also could be errors due to reading or writing letters in reversed manner, for example, reading ‘b’ as ‘d’ or reading ‘w’ as ‘m’. 

Adults with dyslexia often find it hard to perform at their fullest potential at work especially if it includes reading or writing words or numbers. Even though a person’s work doesn’t involve reading or writing they would still face difficulties in carrying out their everyday activities, such as reading or typing messages, or using numbers while buying things or calculating expenses.

Usually, dyslexia is present since childhood and persists till adulthood. But dyslexia can also occur at a later point in life due to brain damage. This is known as acquired dyslexia. There are different causes of acquired dyslexia which are:

• Stroke

• Traumatic brain injury

• Aphasia

• Degenerative disorders like dementia, Alzheimer’s disease

• Brain tumour

• Surgical trauma to the brain during surgery

Dyslexia can be  classified into 5 types which are:

• Surface dyslexia

In this type of dyslexia, the person would have a fairly good phoneme grapheme correspondence and will be able to read unfamiliar words. However, they would have difficulties in reading familiar words quickly as the brain is not able to recognize words as a whole. Hence, they often have more errors while reading familiar words compared to unfamiliar words. The reading speed is also slower than average as they need to process each sound and join them together to read the whole word. 

• Phonological dyslexia

This is the most common type of dyslexia. Here, the phoneme grapheme correspondence is affected. As a result, the person would have difficulty combining sounds according to the phonological rules in order to read a word. Reading unfamiliar and long words is greatly affected due to this. Reading would be slower than average. They would also spell the same word in different ways while reading. There might also be difficulties to recognize the words familiar to them in new or different contexts. Errors in writing are also observed frequently.

• Rapid naming dyslexia

Here, both reading speed and processing speed are affected. If a person with this type of dyslexia is shown numbers, letters and colours rapidly, they are unable to name them correctly. They need more time to visually process images, alphabets or numbers while reading. As a result, reading and writing are much slower than average. Reading aloud is comparatively much more slower than silent reading. If prompted to read faster, they might say non- meaningful words instead of having errors as in other types of dyslexia. 

• Visual dyslexia

In visual dyslexia, the person has difficulties in visual processing as well as remembering visual images. The brain is unable to process the reading page or the image as a whole. Writing is more affected than reading as it is difficult to remember the shape of the alphabets or the sequencing of the alphabets to form a word. A person with visual dyslexia experiences blurring of the text that they are reading which would keep going in and out of focus. They often have difficulties in tracking the text and might read the next word in another line instead of reading words sequentially. Sometimes, texts also appear to be doubled. Due to these, they often have eye strain, frustration and headache after reading for a short period of time. 

• Double deficit dyslexia

This is a combination of phonological dyslexia and rapid naming dyslexia and is the most severe type of dyslexia. The speed of processing and well as the phoneme grapheme correspondence are affected. 

Dyslexia is the difficulty in reading words and numbers due to a brain impairment. It affects a person’s ability to perform daily activities. Dyslexia itself cannot be treated completely especially if it was present since childhood. However, a Speech Language Pathologist can help reduce the effects that it has on daily life by helping clients develop alternative approaches and strategies that would help them with work or activities that require reading and writing.

To speak with one of the speech-language pathologists at Well Said: Toronto Speech Therapy, schedule an initial consultation by clicking the link below or calling (647) 795-5277.