Dyslexia Description And Case Study

Disorder description

Dyslexia is a hereditary “neurodevelopmental disorder” that is recognized by slow and incorrect word recognition and inadequate reading/ spelling skills despite having the ability to learn (include page number). Dyslexia can be acquired, where a reading impairment occurs in individuals who had previously learnt how to read but have lost that ability due severe brain damage. The more common type however, seems to be developmental dyslexia, a reading impairment that occurs in often a child who has not learnt how to read normally in the first place. According to the International Classification of Diseases developmental dyslexia is categorized as a specific reading disorder and is a well-known learning disability. Individuals with developmental dyslexia have a have a specific impairment in attaining reading skills that causes them to have difficulty with accurate and effortless word recognition and spelling. Many children with developmental dyslexia have these impairments despite having intelligence, satisfactory instructions and no obvious neurological or sensory impairment. A study found that 5-10% of children will fail to read to adequate standards regardless of their supportive environment.

Dyslexia can be identified when individuals start to exhibit slow and influent reading, often making mistakes, such as mixing up letters and syllables incorrect word recognition. Dyslexia can be identified in children through various reading tests to assess where their reading abilities lay compared to other children of the same age. Children that are in bottom end of distribution are the ones of concern, with low level performance on tests assessing some aspect of reading. However, a problem with this kind of identification is that some of those children performing low might just be instructional causalities, where they haven’t had the opportunity to learn to read. These children are removed from the classification by providing them with supportive environment to learn to read and then comparing their reading skills after a short period of time to see if they have come up to range. Reading involves many processes and therefore different kinds of dyslexia depending on which reading subskill has not developed.

There are five main types of dyslexia. Surface dyslexia is when individuals have difficulty acquiring whole words. Phonological dyslexia occurs in individuals who have poor knowledge of letter-sound rules. Individuals with Hyperlexia have accuracy in reading aloud of single words and non-words normal for their age but their single word reading comprehension is inadequate. Letter- identification is when single letters cannot be identified. Letter- position dyslexia is when letters are identified accurately but their position within the word is not.

Case study

Patient R.E

Patient R.E is a well-educated university graduate, who has a rare difficulty in reading and spelling non-words. R. E’s developmental dyslexia had been overlooked when she was a child and she went on graduating from university with her reading impairment being unnoticed. Due to her severe respiratory tract infection and allergies she was unable to attend school and was home schooled by her mother most of her life. According to her mother, R.E. spoke well from an early age. She had a decent vocabulary at 2 years of age. However, on starting school, her reading failed to progress. R. E’s mother taught to read at home using the “look-and-sayy” system with single-word stimuli. Patient R.E was first noticed when they observed that R.E could not read a new word aloud until she heard someone else say it. Butterworth and Campbell (1985) then conducted an examination on patient R.E, investigating some parts of reading and writing, to determine exactly where the impairment occurred. The study states that “R.E.’s neuropsychological cerebral organization is normal.” It was observed that R.E performs at above average levels on standard tests of reading, spelling and cognitive ability. However, she performs inadequately on tasks that need knowledge of phonemic structure, like “non-word reading, rhyme judgment and homophone matching”. Butterworth and Campbell found that R.E can read aloud, correctly and without hesitancy, unusual and irregularly spelled words such as “placebo and idyll”. In this test, out of the 45 irregularly spelt words R.E was able to accurately read aloud and provide correct definitions for 33 of them. On the basis of this, R.E can be classified as a good reader. Secondly R.E was asked to read aloud words from a list of 30, three letter non-words. From these words, she was unable to provide the correct pronunciation for nine of them and her reading of each word was very slow and hesitant.

R.E was then asked to read a list of longer non-words, in which out of 20 she was only able to adequately read aloud three of them. She claimed to have found this task very tiring and gave up many times. This study suggested that R.E. shows a particular deficit in the capability to recall and manipulate phonemic information, which is essential to pronounce most non-words stimuli. The study concludes that R.E has deficits related to phonological decoding impairments, shown by her low scores on the phonological awareness tasks.

Cognitive theory

The phonological theory suggests that people with dyslexia have a specific deficit in the, storage or recovery and representation of speech sounds, known as phonemes. According to the phonological theory of dyslexia, individuals lack the capability to attend to and manipulate letter sounds which is crucial for various oral language tasks such as non-word reading. The theory suggests that, it is the process of phonological coding that determines accurate and fluent reading and word recognition, therefore a deficit in this process leads to poor performance in phonemic awareness tasks. To read an alphabetic system, it is necessary to learn the “grapheme- phoneme correspondence” which is the relationship between the letters and the sound it creates. The theory suggests that dyslexic individuals have deficits in representing those sounds in their brain and recalling them, hence there is an impairment with the organization of phoneme-grapheme mappings in dyslexic brains. For example, to read non-words accurately the reader must be able to recall the sounds and map them onto letters and assemble a pronunciation for that word, however, individuals with dyslexia lack this ability.

Evidence

The most significant indication of phonological dyslexia the inability to read non-words. This is due to the fact that non-word reading is more highly dependent on phonological processes compared to reading of words. The discovery that there are dyslexic patients such as patient R.E, that can read words accurately but not non-words supports the phonological theory of dyslexia. Observations of patients like R.E, who have low scores in phonological awareness tasks, and have difficulty in retaining speech in short-term memory supports the theory that dyslexic individuals have a phonological deficit. The finding that R.E has an unusual difficulty in reading and spelling non-words provides evidence that she must have a deficit in the ability to store and recall phonemes. Many other individual case studies and group studies have also found evidence to support the phonological theory of dyslexia. Researchers studied the case of LF, a normal child with average intelligence, who had significant difficulties with phonological tasks. It was observed that even though LF’s reading and spelling skills were proficient, her non-word reading was impaired. It was proposed that LF has severe phonological impairments, shown by her poor performance on phonological tasks.

Snowling, Stackhouse, and Rack (1986) investigated seven developmental dyslexics who were observed to have problematic non-word reading numerous spelling errors. Based on poor their performance on phonological awareness and short-term memory tests, Snowling et al. (1986) conclude that all of the subjects studied can be seen to have phonological deficits. These studies suggest that the subjects lack the phonological representations that are needed in order to learn to read fluently and therefore provide evidence that provides support for the phonological theory.