What is Developmental Dyslexia Effects of Developmental Dyslexia on Development - Research Paper Example

? What is Developmental Dyslexia? 22 February Introduction Many parents and teachers are concerned when children have problems in learning how to read. Scholars have researched these reading problems, which led to understanding the most likely and least likely causes of these difficulties (Vellutino et al., 2004, p.2). Some researchers are interested in studying children who have average intelligence; do not have general learning problems; and whose reading problems are not brought about by external factors such as sensory acuity deficits, socioeconomic status, and other factors (Vellutino et al., 2004, p.2). Reading problems in children reflect their hardship in attaining basic reading sub-skills, such as word identification and phonological or letter-sound decoding, which affect approximately 10 to 15% of school age children (Shaywitz et al., 1992, cited in Vellutino et al., 2004, p.2). Reading problems are often interconnected with cognitive abilities related to reading and other literacy skills (Pavlidou, Kelly, & Williams, 2010, p.145). This paper focuses on developmental dyslexia. Dyslexia is a “specific neurobiological learning disability” (Lyon, Shaywitz, & Shaywitz, 2003, p.2). People with dyslexia have difficulties in correct and/or fluent word recognition, and often have poor spelling and decoding skills (Lyon et al., 2003, p.2). Some of the possible root causes of their reading disability are insufficient facility in word identification due to fundamental deficits in alphabetic coding, and poor phonological skills (Vellutino et al., 2004, p.2). This paper aims to answer the research questions: What is developmental dyslexia? What are the effects of developmental dyslexia on performance and development? These questions are important to answer, so that the underlying causes of reading problems can be properly understood and a wide range of teaching strategies can be considered (Casalis, Cole, & Sopo, 2004). Delayed phonological development, for instance, affects later reading disorders (Nergard-Nilssen, 2006). The paper should benefit teachers and parents of school age children who are teaching them to read. The main body of the paper is focused on the effects of developmental dyslexia on development, particularly implicit learning, low-level auditory discrimination, and morphological awareness. Effects of Developmental Dyslexia on Development Based on several studies, dyslexia affects the reading development of children. It can affect implicit learning and show deficits in phonological and morphological activities. Dyslexia and Effects on Implicit Learning Developmental dyslexia has been related to several deficits in some cognitive functions including phonology, perception (visual and auditory), attention, and memory (Pavlidou et al., 2010, p.144). Several studies showed that people with developmental dyslexia have reading problems from childhood which can have lasting effects until adulthood (Nergard-Nilssen, 2006; Pavlidou, Williams, & Kelly, 2009). The phonological theory has been widely examined among children with dyslexia, in order to understand reading problems (Fischer & Hartnegg, 2004). There are cases, nevertheless, where people with developmental dyslexia show acceptable performance on standard phonological tests, but do not reach fluency in reading (Paulesu et al., 2001 cited in Pavlidou et al., 2010, p.144). It means that they have difficulty in recognizing words easily, despite fine explicit knowledge of grapheme–phoneme connection (Sperling, Lu, & Manis, 2004 cited in Pavlidou et al., 2010, p.144). Developmental dyslexia is theoretically categorized as a learning disorder and so it would be advantageous to examine it within the framework of modern learning literature that is implicit learning (Pavlidou et al., 2010, p.144). Several scholars such as Gombert (2003) and Sperling et al. (2004) maintain that reading concerns an intermingling of explicit and implicit learning abilities, so any deficits in these abilities could avert learners from becoming smooth readers (cited in Pavlidou et al., 2010, p.144). Implicit learning is “the learning process by which we acquire knowledge of the regularities of the learning environment in a passive way (and possibly without awareness)” (Pothos, 2007 cited in Pavlidou et al., 2010, p.144). Implicit learning is believed to have a strong effect on reading in developmental dyslexia (Roodenrys & Dunn, 2008). Pavlidou et al. (2010) studied implicit learning in a group of naturally developing and developmental dyslexic primary school children (9–12 y) using a customized artificial grammar learning task. Performance was monitored through two measures of performance: a perfect free recall (PFR) score and a grammaticality judgment score. Findings showed that developing children with typical abilities showed above-chance performance in both grammaticality and chunk power of the stimuli, while children with developmental dyslexia showed poor implicit learning, despite the substring characteristics. Authors concluded that people with developmental dyslexia may be damaged in their implicit rule abstraction apparatus, which can somewhat give explanation to their continual reading problems. Another study, however, showed different results. Roodenrys and Dunn (2008) aimed to investigate the implicit learning abilities of children with developmental dyslexia through a simple cued reaction time task, which has not been applied with a former student group. Sampling included twenty-three children with developmental dyslexia and 37 normally developing children, between the ages of 8 and 10. The results showed that though they had slower response times, dyslexic children had the same level of implicit learning as normal readers. This means that they are not impaired in their implicit learning mechanism. Authors concluded that dyslexic individuals are impaired on explicit learning tasks, such as reading, spelling and writing, but they do not have problems in implicit tasks. They proposed that there are two divided systems of learning, each having particular mechanisms. Studies on implicit learning indicate varying levels of implicit learning abilities. For Pavlidou et al. (2010), their dyslexic respondents showed poor implicit learning despite the substring characteristics, while Roodenrys and Dunn (2008) provided evidence that dyslexic individuals do not have problems in implicit learning tasks. Dyslexia and Effects on Low-Level Auditory Discrimination Evidence provided that dyslexics have difficulties with low-level auditory and visual processing, specifically deficits in auditory temporal and spectral resolution (Mc Anally & Stein, 1996; Tallal, 1980 cited in Fischer & Hartnegg, 2004, p.106) and that the responsiveness to dynamic auditory and visual non-linguistic stimuli can forecast non-word reading capability in both dyslexic and normal readers (Fischer & Hartnegg, 2004, p.106). Phonological awareness, which is described as critical to learning reading and writing abilities may rely on fundamental (low-level) auditory skills (Fischer & Hartnegg, 2004, p.106). Still, others contended that impaired auditory low-level skills may neither be adequate nor essential prerequisites for developing dyslexia (Rosen, 1999; Watson & Muller, 1993 cited in Fischer & Hartnegg, 2004, p.106). At the same time, auditory difficulties of dyslexics are particular to linguistic skills (Schulte–Korne et al., 1998 cited in Fischer & Hartnegg, 2004, p.106). Some behavioral studies propose that a range of aspects of auditory perception of non-linguistic and language-related stimuli is mainly full-grown by school age (Allen & Wightman, 1992; Walley, Pisoni, & Aslin, 1984 cited in Fischer & Hartnegg, 2004, p.106). Some of the auditory abilities such as identifying frequency differences in long tones are believed to have attained adult levels previously by the age of 6 months (Fischer & Hartnegg, 2004, p.106). These perceptual abilities are believed to be dependent on the individual’s auditory experience (Trehub, Schneider, & Henderson, 1995 cited in Fischer & Hartnegg, 2004, p.106) and may be at diverse developmental levels for different children that have similar ages (Fischer & Hartnegg, 2004, p.106). When examining sensory abilities in dyslexia, researchers have to consider natural development during school years. Absolute auditory thresholds, frequency strength and temporal resolution grow further as people age. Fischer and Hartnegg (2004) used five new auditory tasks to learn the development of low-level auditory discrimination. Findings showed that the development lasts up to the age of 16 to 18 years (on an average). High numbers of subjects were classified as low performers (LP), because they could not carry out one or the other tasks at its easiest level and no threshold value could be determined. For the dyslexics, the occurrence of LP was significantly increased in all tasks and age groups, when compared with the controls. Authors concluded that temporal auditory processing is damaged in many dyslexics. The dynamic visual and the optomotor systems may also display deficits in dyslexic subjects and it may be significant to look at these deficits also when examining explicit sensory problems in the accomplishment of reading and spelling skills (Fischer & Hartnegg, 2004). Dyslexia and Effects on Morphological Awareness In alphabetic systems, written units take morphological and phonological information, and evidence showed that phonemes and morphemes are processed in alphabets (Casalis, Cole, & Sopo, 2004, p.115). Morphology pertains to an organizational level of language that handles the smallest units of meaning: the morphemes (Casalis, Cole, & Sopo, 2004, p.115). The expression "unacceptable", for example, has three morphemes (un, accept, able), and the denotation of the whole word is approximately the result of the combination of the morphemes (Casalis, Cole, & Sopo, 2004, p.115). There are diverse kinds of morphemes: roots, that may or not be words themselves ("accept"); and bound morphemes, that cannot be words, such as the prefix ("un") and the suffix ("able") (Casalis, Cole, & Sopo, 2004, p.115). There are also inflections that tend to reflect gender, number, and tense (Casalis, Cole, & Sopo, 2004, p.115). Hence, the meaning of an unidentified word can be deduced from breaking it down into its morphemic constituents, and new words can also be made from morphemes (Casalis, Cole, & Sopo, 2004, p.115). Casalis, Cole, and Sopo (2004) studied the morphological awareness in developmental dyslexia. This is because of the paucity of research on their morphological awareness, which affects reading development. The study compared the performance of dyslexic children in a set of morphological tasks with the performance of children who have the same reading-level and chronological age. For all tasks, the dyslexic group performed below the performance of the control group, which indicates that morphological awareness cannot be developed entirely separately of reading experience and/or phonological skills. Dyslexic children also performed poorly in morphemic segmentation tasks. Discussion The studies agree that dyslexia affects reading abilities. Studies differed on whether dyslexia impairs implicit learning. They agree, nevertheless, that the dynamic visual and the optomotor systems may also display deficits in dyslexic subjects and it may be significant to look at these deficits also when studying explicit sensory problems in the accomplishment of reading and spelling skills. Dyslexic children also show deficits in oral morphological abilities. They may have problems with morphological segmentation, most likely due to their poor phonological skills. Their understanding of the relationship between base and derived forms in meaningful contexts matches to their reading level. This suggests that their morphological skills expand, at least in part, separately to their phonological skills. The literature needs to further understand the relationship between morphological segmentation abilities and phonological skills. In addition, it is limited to studying certain aspects of learning, mostly reading. Additional studies on grammar development and literacy skills in general, as adults, should also be pursued. These studies implicate that developmental dyslexia can affect reading experience and reading skills development, which can have cognitive effects on vocabulary and grammar too. Developmental dyslexia can then negatively affect the development of fluent reading skills, which can affect academic performance in reading subjects. References Casalis, S., Cole, P., & Sopo, D. (2004). Morphological awareness in developmental dyslexia. Annals of Dyslexia, 54 (1), 114-138. Fischer, B. & Hartnegg, K. (2004). On the development of low-level auditory discrimination and deficits in dyslexia. Dyslexia, 10 (2), 105-118. Lyon, G. R., Shaywitz, S.E., & Shaywitz, B.A. (2003). A definition of dyslexia. Annals of Dyslexia, 53, 1-14. Nergard-Nilssen, T. (2006). Longitudinal case-studies of developmental dyslexia in Norwegian. Dyslexia, 12 (4), 231-255. Pavlidou, E.V., Kelly, M. L., & Williams, J.M. (2010). Do children with developmental dyslexia have impairments in implicit learning? Dyslexia, 16 (2), 143-161. Pavlidou, E.V., Williams, J.M., & Kelly, L.M. (2009). Artificial grammar learning in primary school children with and without developmental dyslexia. Annals of Dyslexia, 59 (1), 55-77. Roodenrys, S. & Dunn, N. (2008). Unimpaired implicit learning in children with developmental dyslexia. Dyslexia, 14 (1), 1-15. Vellutino, F.R., Fletcher, J.M., Snowling, M.J., & Scanlon, D.M. (2004). Specific reading disability (dyslexia): what have we learned in the past four decades? Journal of Child Psychology & Psychiatry, 45 (1), 2-40. Read More