Cognitive Disorders of Dyslexia - Term Paper Example

Cognitive Disorders Name Institution Date Introduction Cognitive disorders are a common occurrence both to children and adults. The disorders can either be acquired or developmental. This paper seeks to examine dyslexia as one of the major cognitive disorders. The scope of the paper will be grounded on examining the concept dyslexia. The paper will further examine the phonological dyslexia as an impairment within the disorder. Lastly, the paper will examine the manner in which dual route model accounts for phonological dyslexia. Description of Dyslexia Dyslexia is a common condition that impacts the way in which the brain process various spoken and written language. It is often associated with reading troubles. Some specialists refer to it as reading disability (Spafford and Grosser, 2005). Consequently, Dyslexia can also affect the spelling, writing and speaking. Dyslexia is a lifelong condition that children can have for their entire life. This does not mean that the child should remain unsuccessful and unhappy throughout their lifetime. There exist various teaching tools and strategies that can help children cope well with this disorder. Moreover, most individuals with Dyslexia have various careers in science, arts and business (Moats et al., 2008). Dyslexia not only affects the reading and writing skills, but also affects other skills such as the social skills. Dyslexia affects the social life of children in several ways. The children may struggle in school making them feel inferior among their friends in school. The child may opt to avoid group activities or stop making friends due to their nature. Parents should strive and help their children with dyslexia to develop self-esteem and develop a sense of humor. Listening comprehension is another problem brought about by Dyslexia. Children affected by dyslexia tend to be good listeners than readers. However, it can be difficult to filter background noise due to dyslexia. This means that the child may find it difficult to understand what the teacher says. This can be reduced when the child sits next to the teacher to avoid various distractions (In Arfe, 2014). Cognitive impartment in Dyslexia Phonological dyslexia Phonological impairment is a reading disability which is a form of acquired dyslexia. It can arise from a stroke, brain injury or progressive illness that possesses significant challenge to the reading abilities. The main distinguishing symptom of phonological dyslexia is that the ability to read and pronounceable non-words is affected, while the ability to read familiar words are not affected. Various studies suggest that capability of reading non-words can be developed if the non-words are members of the pseudo homophones. Individuals with phonological impairment are capable of reading using whole word method, but they struggle in sounding words (Moats et al., 2008). Phonological awareness is a major skill in early spelling and reading development. It provides the learners with the ability to recognize how words are words are made up of various units of sound such as phonemes. Changes in the phonemes that make up a word can change the meaning of such words. This leads to leading impairment of children with dyslexia. The patients also have a problem with their vocabulary memory. This is the ability to remember series of verbal information for a shorter period. Lack of proper vocabulary memory creates learning difficulty among the children with Dyslexia (Selikowitz, 2012). Several studies have suggested that individuals with phonological dyslexia possess a good reading ability if such individuals developed a large vocabulary before suffering the brain damage. In the past, it was believed that phonological dyslexia was caused by lexicality, however, it has been discovered that other factors such concreteness and imageability has a significant impact on the phonological dyslexia. A recent study found out that out of twelve patients, eleven were more accurate when reading words higher imageability (Moats et al., 2008) Dual route model Dual route model is a computational reading model intended to explain how skilled readers undertake reading activities. Within the dual route model information processing occurs in a more cascaded fashion. The model consist of three routes, that is, lexical non-semantic, lexical semantic and GPC route. There exist some interacting layers within every route. These layers have various sets of units. These units symbolize smallest personal symbolic parts of the Dual Route Model, such as letter unit and words in the orthographic lexicon. The units of different layers interact in two ways. The first way is through inhibition; this is where the activation of a given unit makes it difficult for the activation. The second way is through excitation; this is where the activation of a given unit leads to the activation of the other unit (Jackson and Coltheart, 2010). How the Dual Route Model accounts for Phonological Dyslexia Dual Route Model reads words aloud by use of two separate procedures. In the lexical route, entry into the orthographic lexicon is selected by the orthographic input via interactive activation that latter activates the required phonological output. The non-lexical route takes various orthographic inputs, it parses the input into graphemes, and then it uses a set of rules to convert the graphemes into various phonemes, and then it assembles the phonemes into word output. Exceptional words can only be read by the lexical route. This is because these words often break the rules of the phoneme- grapheme correspondence. Non-words can only be read by non-lexical route, this is because such words are not in the orthographical lexicon and have not been encountered before. Both non-lexical route and lexical route leads to a successful reading of words. The dual route model was developed for skilled readers, and it does not change over time. Consequently, its proponents argue that it provides a coherent and velar account of developing various reading difficulties. The model has been used in simulating individual differences in developing reading disorder (Jürgen and Heinz, 2010). Through lexical route, skilled readers are in a position to recognize known words by sight alone through a lookup procedure. As to this model, any word learned by the reader is represented in their mental database of words. When skilled readers see and recognize written words, they can access the entry of the word in the dictionary and retrieve the required information about the pronunciation of the word. Every learned word is contained in the internal lexicon. However, this model does not allow the reading of non-words (Coltheart et al., 2008). The theory accounts for the poor knowledge of letter sound rules. The theory can be used in explaining various patterns of data that are connected to different types of disordered reading both acquired and developed. Most children with difficulty in reading always rely on a sub-lexical route as they read. Studies shows that children can decode letter by letter, non-words accurately but at a lower speed. In decision tasks, children find it difficult to differentiate between pseudo homophones and words, thereby indicating that they had impairment in their internal lexicons. Since children with the reading disorder have impaired lexical routes and slow reading speeds, there are suggestions that these processes are also involved in the fast naming of words and lexical route. There are also other studies that have confirmed that naming words are correlated the lexical route knowledge than with sub- lexical route knowledge. The same results were found true with patients with ADHD. According to the research, reading disorder is similar and has common properties to ADHD, Rapid reading, lexical route and sub-lexical route processing as well (Selikowitz, 2012). The traditional dual-route review suggested that phonological dyslexia arises from various damages to the non-lexical route, damage on the lexical route leads to surface dyslexia. Systematic lesioning of Dual Route Model has been used to specify the nature of difficulties in surface dyslexia and acquired phonological dyslexia. Jackson and Coltheart (2010) suggest that the damage to the orthographic input lexicon of the dual route model leads to the acquired surface dyslexia. They further argue that there is no lesion that is capable of producing all the patterns displayed by dyslexics with acquired phonological dyslexia. Nickles et al. (2008), suggests that the data of some patients were simulated by the damage on the phoneme-grapheme procedures. In a study by Coltheart et al., (2008), children with dyslexia exhibited deficit on three main predictor activities that are directly related to the processing levels in the Dual route model. The first deficit was on the letter search; this indicated problems in the positioning of specific processing of letters. Deficits in naming pictures suggested impairment in access to the phonological lexicon and finally, the deficit in the phoneme matching showed impairment in the phoneme system of the dual route model. Hence, according to the data, it is true that children with dyslexia have deficits in sublexical and lexical route as well as at common processing levels for both the two routes. Alternatively, the study failed to single out deficits in the orthographic access (Coltheart et al., 2008). The average data indicate that children with Dyslexia show several deficits as a group; it is true that every child had only one deficit. As to this, the multiple deficit patterns appear due to the averaging process. The study thus considered personal data and expressed the deficits of every individual of three tasks concerning the z-score that shows the difference between dyslexia and controls. The z- scores was computed for all the children with dyslexia with respect to standard deviation and control mean. The study found out that out of 24 children with dyslexia, five had a triple deficit, nine had a double deficit, six had a single deficit and four had no deficit. These data shows that for many children with dyslexia, reading impairment is attributed to several deficits but not on a single deficit (Robin et al., 2013). Supporting Evidence The dual route model account for the poor knowledge of letter sound rules is supported. A study conducted Elise et all (nd ) to examine phonological dyslexia ; a test case for reading models, disclosed that indeed the dual route model does account for phonological dyslexia . The methodology of the study involved an experimental study of two skilled readers who had encountered brain damage. The findings of the study disclosed that although the two patients were able to accurately read familiar words loudly, they were actually unable to read nonwords. The findings of the study therefore challenges the propositions made by the evolutionally and connectionist theory that phonological dyslexia arises from phonological deficits but rather, it’s a deficit that selectively impacts on the mechanisms of reading that are responsible for pronouncing non word sounds, as indicated by the dual route model. Studies conducted by various researcher such as; Beauvois and Derousné (1985) and Berndt et al (1996) highlights that the Dual route model provides two kinds of mechanism. One of the mechanism is the lexical route as stated earlier. The lexical route is in charge of recovering stored information concerning phonology, semantics and orthography of words that are familiar. Another substitute route is the non – lexical route which enables readers to retrieve sounds of words written down through approaches that convert letters into the sounds that resemble . In most cases, the non- lexical route has a deficiency in the sense that it does not provide information concerning the meaning of the word essentially in a language that is understandable. Based on the fact that the non- lexical route has the role of deriving nonword sounds , when it is selectively damaged it can result to phonological dyslexia . Conclusion The above discussion presents an in-depth analysis of dyslexia as one of the cognitive impairments. The study further discuses phonological dyslexia as genre of dyslexia. The paper argues that the Dual Route Model can be used to explain the occurrence of phonological dyslexia. In conclusion, it can be stated that dyslexia is a cognitive impairment that can affect the reading ability of an individual, as a result it is essential to find suitable strategies to reduce the disorder. References Beauvois, M and Derousné, J. (1985). The “phonemic” state in the non-lexical reading process: Evidence from a case of phonological alexia. Lawrence Erlbaum Associates Ltd Berndt, R, Haendiges, N, Wayland, S, Mitchum, C. (1996). An Investigation of nonlexical reading impairments. Cognitive Neuropsychology. 13, 763-801. Coltheart M, Rastle K, Perry C, Langdon R, Ziegler J. (2008). DRC: A dual route model of visual word recognition and reading aloud. Psychological Review. 108(1):204– 256. Elise, C, Michele Miozzo, M, and Yaakov , S.. (nd ). Phonological dyslexia: a test case for reading models. Taub Institute for Research. In Arfé, B. (2014). Writing development in children with hearing loss, dyslexia, or oral language problems: Implications for assessment and instruction. Jackson, N and Coltheart, M . (2010). Routes to reading failure and success: Toward an integrated cognitive psychology of atypical reading. Psychology Press. Jürgen B and Heinz W.(2010). A dual-route method on poor reading in a regular orthography: Evidence from phonological and orthographic lexical decisions. Cogn Neuropsychol. 25(5): 653–676. Moats, L. C., International Dyslexia Association and Dakin, K. E. (2008). Basic facts about dyslexia & other reading problems. Baltimore, Md: International Dyslexia Association. Nickels L, Coltheart M, Saunders S, Biedermann B, and Tree J (2008). Computational modeling of phonological dyslexia: How does the DRC model fare? Cognitive Neuropsychology. 25(2):165–193. Robin L. Pennington B. and Olson R.(2013). Subtypes of developmental dyslexia: Testing the predictions of the dual-route and connectionist frameworks. Cognition. 126(1): 20–38. Selikowitz, M. (2012). Dyslexia and other learning difficulties. Sage. Spafford, C. A., & Grosser, G. S. (2005). Dyslexia and reading difficulties:resource guide for working with all struggling readers. Boston: Pearson/Allyn and Bacon. Read More