Strephosymbolia was Samuel Orton's theory of dyslexia which he first published in 1925. The root strepho is Ancient Greek for "twisted" or "reversed" and he used this in preference to the phrase "word blindness", which he thought inaccurate as the difficulty was not that those with strephosymbolia could not see the words but that they had difficulty comprehending them. As he developed his theory, he attributed the difficulty to an imperfect dominance of the hemisphere of the brain which processed the symbols when reading, being confused by a residual but reversed equivalent in the other hemisphere. [1]
Dyslexia, previously known as word blindness, is a learning disability that affects either reading or writing. Different people are affected to different degrees. Problems may include difficulties in spelling words, reading quickly, writing words, "sounding out" words in the head, pronouncing words when reading aloud and understanding what one reads. Often these difficulties are first noticed at school. The difficulties are involuntary, and people with this disorder have a normal desire to learn. People with dyslexia have higher rates of attention deficit hyperactivity disorder (ADHD), developmental language disorders, and difficulties with numbers.
In neuroscience and psychology, the term language center refers collectively to the areas of the brain which serve a particular function for speech processing and production. Language is a core system that gives humans the capacity to solve difficult problems and provides them with a unique type of social interaction. Language allows individuals to attribute symbols to specific concepts, and utilize them through sentences and phrases that follow proper grammatical rules. Finally, speech is the mechanism by which language is orally expressed.
Visual thinking, also called visual or spatial learning or picture thinking, is the phenomenon of thinking through visual processing. Visual thinking has been described as seeing words as a series of pictures. It is common in approximately 60–65% of the general population. "Real picture thinkers", those who use visual thinking almost to the exclusion of other kinds of thinking, make up a smaller percentage of the population. Research by child development theorist Linda Kreger Silverman suggests that less than 30% of the population strongly uses visual/spatial thinking, another 45% uses both visual/spatial thinking and thinking in the form of words, and 25% thinks exclusively in words. According to Kreger Silverman, of the 30% of the general population who use visual/spatial thinking, only a small percentage would use this style over and above all other forms of thinking, and can be said to be true "picture thinkers".
Dyscalculia is a disability resulting in difficulty learning or comprehending arithmetic, such as difficulty in understanding numbers, learning how to manipulate numbers, performing mathematical calculations, and learning facts in mathematics. It is sometimes colloquially referred to as "math dyslexia", though this analogy is misleading as they are distinct syndromes.
Dysgraphia is a neurological disorder and learning disability that concerns impairments in written expression, which affects the ability to write, primarily handwriting, but also coherence. It is a specific learning disability (SLD) as well as a transcription disability, meaning that it is a writing disorder associated with impaired handwriting, orthographic coding and finger sequencing. It often overlaps with other learning disabilities and neurodevelopmental disorders such as speech impairment, attention deficit hyperactivity disorder (ADHD) or developmental coordination disorder (DCD).
A reading disability is a condition in which a person displays difficulty reading. Examples of reading disabilities include: developmental dyslexia, And alexia,
The Geschwind–Galaburda hypothesis is a neurological theory proposed by Norman Geschwind and Albert Galaburda in 1987. The hypothesis posits there are sex differences in cognitive abilities by relating them to lateralisation of brain function. The maturation rates of cerebral hemispheres differ and are mediated by circuiting testosterone levels, which are substantially influenced during the foetal and post-puberty development stages.
Samuel Torrey Orton was an American physician who pioneered the study of learning disabilities. He examined the causes and treatment of dyslexia.
Pure alexia, also known as agnosic alexia or alexia without agraphia or pure word blindness, is one form of alexia which makes up "the peripheral dyslexia" group. Individuals who have pure alexia have severe reading problems while other language-related skills such as naming, oral repetition, auditory comprehension or writing are typically intact.
The phonological deficit hypothesis is a prevalent cognitive-level explanation for the cause of reading difficulties and dyslexia. It stems from evidence that individuals with dyslexia tend to do poorly on tests which measure their ability to decode nonsense words using conventional phonetic rules, and that there is a high correlation between difficulties in connecting the sounds of language to letters and reading delays or failure in children.
Deep dyslexia is a form of dyslexia that disrupts reading processes. Deep dyslexia may occur as a result of a head injury, stroke, disease, or operation. This injury results in the occurrence of semantic errors during reading and the impairment of nonword reading.
The Arrowsmith School is a private school in Toronto, Ontario, for children in Grades 1 to 12 with learning disabilities. The original Arrowsmith School was founded in Toronto in 1980 by Barbara Arrowsmith Young. A second location was opened in May 2005 in Peterborough, Ontario. The Eaton Arrowsmith School, which is modelled on the Toronto school and founded by Howard Eaton, was opened in 2005 in Vancouver, British Columbia with two further branches established in Canada and one in the United States between 2009 and 2014.
Language-based learning disabilities or LBLD are "heterogeneous" neurological differences that can affect skills such as listening, reasoning, speaking, reading, writing, and math calculations. It is also associated with movement, coordination, and direct attention. LBLD is not usually identified until the child reaches school age. Most people with this disability find it hard to communicate, to express ideas efficiently and what they say may be ambiguous and hard to understand It is a neurological difference. It is often hereditary, and is frequently associated to specific language problems.
The history of dyslexia research spans from the late 1800s to the present.
Dyslexia is a reading disorder wherein an individual experiences trouble with reading. Individuals with dyslexia have normal levels of intelligence but can exhibit difficulties with spelling, reading fluency, pronunciation, "sounding out" words, writing out words, and reading comprehension. The neurological nature and underlying causes of dyslexia are an active area of research. However, some experts believe that the distinction of dyslexia as a separate reading disorder and therefore recognized disability is a topic of some controversy.
Dyslexia is a complex, lifelong disorder involving difficulty in learning to read or interpret words, letters and other symbols. Dyslexia does not affect general intelligence, but is often co-diagnosed with ADHD. There are at least three sub-types of dyslexia that have been recognized by researchers: orthographic, or surface dyslexia, phonological dyslexia and mixed dyslexia where individuals exhibit symptoms of both orthographic and phonological dyslexia. Studies have shown that dyslexia is genetic and can be passed down through families, but it is important to note that, although a genetic disorder, there is no specific locus in the brain for reading and writing. The human brain does have language centers, but written language is a cultural artifact, and a very complex one requiring brain regions designed to recognize and interpret written symbols as representations of language in rapid synchronization. The complexity of the system and the lack of genetic predisposition for it is one possible explanation for the difficulty in acquiring and understanding written language.
Dyslexia is a disorder characterized by problems with the visual notation of speech, which in most languages of European origin are problems with alphabet writing systems which have a phonetic construction. Examples of these issues can be problems speaking in full sentences, problems correctly articulating Rs and Ls as well as Ms and Ns, mixing up sounds in multi-syllabic words, problems of immature speech such as "wed and gween" instead of "red and green".
Educational neuroscience is an emerging scientific field that brings together researchers in cognitive neuroscience, developmental cognitive neuroscience, educational psychology, educational technology, education theory and other related disciplines to explore the interactions between biological processes and education. Researchers in educational neuroscience investigate the neural mechanisms of reading, numerical cognition, attention and their attendant difficulties including dyslexia, dyscalculia and ADHD as they relate to education. Researchers in this area may link basic findings in cognitive neuroscience with educational technology to help in curriculum implementation for mathematics education and reading education. The aim of educational neuroscience is to generate basic and applied research that will provide a new transdisciplinary account of learning and teaching, which is capable of informing education. A major goal of educational neuroscience is to bridge the gap between the two fields through a direct dialogue between researchers and educators, avoiding the "middlemen of the brain-based learning industry". These middlemen have a vested commercial interest in the selling of "neuromyths" and their supposed remedies.
Images and other stimuli contain both local features and global features. Precedence refers to the level of processing to which attention is first directed. Global precedence occurs when an individual more readily identifies the global feature when presented with a stimulus containing both global and local features. The global aspect of an object embodies the larger, overall image as a whole, whereas the local aspect consists of the individual features that make up this larger whole. Global processing is the act of processing a visual stimulus holistically. Although global precedence is generally more prevalent than local precedence, local precedence also occurs under certain circumstances and for certain individuals. Global precedence is closely related to the Gestalt principles of grouping in that the global whole is a grouping of proximal and similar objects. Within global precedence, there is also the global interference effect, which occurs when an individual is directed to identify the local characteristic, and the global characteristic subsequently interferes by slowing the reaction time.
Anne Castles is a cognitive scientist of reading and language, with a particular focus on reading development and developmental dyslexia.