Dyslexia is a learning disorder that affects an individual's ability to read, write, and spell. It is one of the most common learning disorders, with estimates suggesting that it affects up to 15% of the population. Despite its prevalence, the exact cause of dyslexia is still not fully understood, and there are several theories that have been proposed to explain its development.
One theory of dyslexia suggests that it is caused by differences in the structure and function of the brain. This theory is supported by brain imaging studies that have shown that individuals with dyslexia have structural differences in specific areas of the brain, including the left hemisphere and the cerebellum. These differences may lead to difficulties in processing and interpreting language, which can manifest as difficulty with reading, writing, and spelling.
Another theory of dyslexia is that it is caused by genetic factors. Studies have shown that dyslexia tends to run in families, and researchers have identified several specific genes that may be associated with dyslexia. These genes may affect the development and function of the brain, leading to the symptoms of dyslexia.
Another theory suggests that dyslexia may be caused by a combination of genetic and environmental factors. For example, exposure to certain toxins or drugs during pregnancy or early childhood may increase the risk of developing dyslexia. Additionally, certain experiences during early development, such as a lack of exposure to language or inadequate reading instruction, may also contribute to the development of dyslexia.
There is also some evidence to suggest that dyslexia may be caused by problems with the way that the brain processes sensory information. Some individuals with dyslexia may have difficulty processing visual or auditory information, which can make it difficult for them to process and understand written language.
Overall, the exact cause of dyslexia is still not fully understood, and it is likely that there are multiple factors that contribute to its development. Further research is needed to better understand the underlying causes of dyslexia and to develop more effective strategies for addressing this learning disorder.
Theories of developmental dyslexia: insights from a multiple case study of dyslexic adults
Prevalence figures cited in the literature, however, can be highly variable i. The magnocellular theory, unique in its ability to account for all manifestations of dyslexia, is undoubtedly attractive. When these children reached young adulthood, another follow-up study brought the following to light: "The experimental group had become productive, functioning adults, while the control group, for the most part, had been institutionalized as mentally retarded. There are different theories of the causes and consequences of dyslexia and dysgraphia. There was some merit to these new theories of dyslexia, although different languages have different complexities of phonological rules. Despite all these theories and all the intervention efforts based on them, not to mention the vast amounts of money expended in the process, the numbers of dyslexics continue to escalate. Ridsdale 2004 has pointed out the connection between dyslexia and low self-esteem, behavioural difficulties, withdrawal and depression.
Possible Causes of Dyslexia: Understand It Then Overcome It
Because we felt that dissociations between disorders would be the most informative, we selected a special dyslexic population, consisting of university students. Another criticism of this theory is that these phonological skills can be recovered on extensive training. A second measure was taken with a different ordering of the 50 pictures. The dependent measure was total time taken, and was assessed twice. Several studies using functional imaging techniques that compared the brain activation patterns of readers with and without dyslexia show potentially important patterns of differences. The double-deficit theory proposes that dyslexic individuals have a single deficit in one of these skills or the double deficit in both skills. Neither class of stimulus flickered, but in all other respects e.
It is also impossible to explain how a neurological dysfunction can be more prevalent in specific areas or countries. But under the surface I live in a turmoil. These include broad language skills such as expressive and receptive language, vocabulary, morphology, and syntax Scarborough, 2005. In general each of the explanations explains some of the evidence from dyslexia but none of them explain all of it. Some authors Shaywitz et al.
They are slower at rhyming as well. There are causal connections between abnormalities in the magnocellular system and behavioral signs of dyslexia. Besides that, it can be seen that for a children with dyslexia, it takes them a lot of time to sound out a word. Five months later, after working faithfully according to a customized Audiblox program for two half-hour sessions per day, five days per week, Werner's reading efficiency was retested. His reading speed was only 107 words per minute. Indeed, challengers of the phonological theory do not dispute the existence of a phonological deficit and its contribution to reading retardation; rather, they uphold that the disorder is much more extended, having its roots in general sensory, motor or learning processes, and that the phonological deficit is just one aspect or consequence of the more general disorder. The present study Our aim was to produce data that would enable us to start answering questions concerning associations, dissociations and, eventually, causal relationships between sensory, motor, phonological and reading disorders.
Who can diagnose dyslexia? In addition there are two Kana syllabaries, which — like our Latin alphabet — use symbols to represent sounds. And battle he did. In each condition, subjects first had to tap for 30 s in synchrony with the metronome, then the metronome stopped and they had to continue for 30 s at exactly the same pace. Two modulation frequencies were used 2 and 240 Hz. However, there are several theories proposed by specialist doctors and researchers and also some evidence which can help in clarifying the origin of this condition and they believed that these are the possible causes which are genetic inheritance, neurological differences, phonological disorder and last but not least, hearing problem. Neither was FM detection at 240 Hz, since at this frequency the modulations are not resolved by the auditory system.
Accessed April 6, 2022. All the members of his family were musicians and from the moment of his birth he was continually exposed to music. Stimulus contrast was again enveloped using a temporal Gaussian function. Prevalence may differ according to gender, with clinicians typically citing a ratio of 2—3 boys for every girl. Total naming time was recorded irrespective of accuracy. . Neurons die each day, too, keeping the overall number more or less balanced, with a slow loss of cells as we age.
The date—gate continuum varied both the spectrum of the initial release burst and the starting frequencies of the second and third formants to signal the change in place of articulation. Indeed, they are struggling in phonological processing. In coherent motion detection, it appears that our subjects had much higher thresholds than in comparable published studies e. Acknowledgements We thank Kingsley Betts, Helen Cheng, Andrew Milne and Robin Wilson for help collecting the data; Eamon McCrory, Sarah Griffiths, Cordelia Fine and Elizabeth Hill for various contributions; John Morton, Rod Nicolson, Angela Fawcett and members of the ICN Dyslexia Club for discussions and advice; Heather van der Lely for providing the two syntax tests and Jon Driver for allowing us access to his soundproof room. The term dyslexiawas coined from the Greek words dys, meaning ill or difficult, and lexis, meaning word.
Thus I conclude by stating that Dyslexia is an impairment of multiple Brain systems. A phonology; B audition; C vision; D cerebellar function. Movements of the CoP between the feet and the ground were calculated from the distribution of forces measured from a force plate Kistler type 9287; Kistler Instrumente, Winterthur, Switzerland. For instance, if a phonological and a visual disorder can appear independently, an individual having both disorders should be less likely to succeed academically than an individual with just one of them. Accessed April 6, 2022. Fortunately, there are many researches are carried out in the recent years due to the advancement of technology in brain-scanning.
