Word Blindness Research Articles

Understanding dyslexia

The word ‘dyslexia’ was originally coined from the Greek and, taken literally, means ‘difficulty with words’. The old way of describing it was ‘word blindness’ – an inability to read letters and numbers in the right order. However, that's far from the whole picture.

Varieties of alexia. Word and letter blindness

Varieties of alexia. Word and letter blindness

Right hemiparalexia vera: word blindness for the right part of words despite normal fields of vision

Right hemiparalexia vera: word blindness for the right part of words despite normal fields of vision

Right hemiparalexia vera: word blindness for the right part of words despite normal fields of vision

A 30-year-old woman with premature hyperhomocysteinemic atherosclerosis and left subcortical occipital lobe infarction made reading errors restricted to the right end of words. For instance, when confronted with the word ‘diameter’, she would read ‘diagram’. She had no hemianopia and no problems with writing words. Calculation, color vision, and eye movements were normal. She was not aphasic. Her reading disturbance was classified as hemiparalexia. Most hemiparalexics make errors in the left part of the word. Such left hemiparalexia is caused by an interhemispheric disconnection between the right visual association area and the left angular gyrus. The condition described in this article is characterized by reading errors in the right part of the word despite fully normal visual fields. Right hemiparalexia has been described in a patient with right hemianopia, but I have been unable to find any previous report of right hemiparalexia despite normal fields of vision. Right hemiparalexia vera seems to be a suitable name for the reading disorder of this woman. Her condition was caused by a left, mainly subcortical, occipital ischemic infarct probably leading to a disruption of the intrahemispheric connections between the left visual association area and the left angular gyrus. Right hemiparalexia vera can be regarded as the next chapter in the history of word blindness, which started in 1676 when Johannes Schmid published a case report entitled ‘De oblivione lectionis ex apoplexia, salva scriptione’ (On the loss of reading with saved writing caused by apoplexia).

From sensation to cognition

Sensory information undergoes extensive associative elaboration and attentional modulation as it becomes incorporated into the texture of cognition. This process occurs along a core synaptic hierarchy which includes the primary sensory, upstream unimodal, downstream unimodal, heteromodal, paralimbic and limbic zones of the cerebral cortex. Connections from one zone to another are reciprocal and allow higher synaptic levels to exert a feedback (top-down) influence upon earlier levels of processing. Each cortical area provides a nexus for the convergence of afferents and divergence of efferents. The resultant synaptic organization supports parallel as well as serial processing, and allows each sensory event to initiate multiple cognitive and behavioural outcomes. Upstream sectors of unimodal association areas encode basic features of sensation such as colour, motion, form and pitch. More complex contents of sensory experience such as objects, faces, word-forms, spatial locations and sound sequences become encoded within downstream sectors of unimodal areas by groups of coarsely tuned neurons. The highest synaptic levels of sensory-fugal processing are occupied by heteromodal, paralimbic and limbic cortices, collectively known as transmodal areas. The unique role of these areas is to bind multiple unimodal and other transmodal areas into distributed but integrated multimodal representations. Transmodal areas in the midtemporal cortex, Wernicke's area, the hippocampal-entorhinal complex and the posterior parietal cortex provide critical gateways for transforming perception into recognition, word-forms into meaning, scenes and events into experiences, and spatial locations into targets for exploration. All cognitive processes arise from analogous associative transformations of similar sets of sensory inputs. The differences in the resultant cognitive operation are determined by the anatomical and physiological properties of the transmodal node that acts as the critical gateway for the dominant transformation. Interconnected sets of transmodal nodes provide anatomical and computational epicentres for large-scale neurocognitive networks. In keeping with the principles of selectively distributed processing, each epicentre of a large-scale network displays a relative specialization for a specific behavioural component of its principal neurospychological domain. The destruction of transmodal epicentres causes global impairments such as multimodal anomia, neglect and amnesia, whereas their selective disconnection from relevant unimodal areas elicits modality-specific impairments such as prosopagnosia, pure word blindness and category-specific anomias. The human brain contains at least five anatomically distinct networks. The network for spatial awareness is based on transmodal epicentres in the posterior parietal cortex and the frontal eye fields; the language network on epicentres in Wernicke's and Broca's areas; the explicit memory/emotion network on epicentres in the hippocampal-entorhinal complex and the amygdala; the face-object recognition network on epicentres in the midtemporal and temporopolar cortices; and the working memory-executive function network on epicentres in the lateral prefrontal cortex and perhaps the posterior parietal cortex. Individual sensory modalities give rise to streams of processing directed to transmodal nodes belonging to each of these networks. The fidelity of sensory channels is actively protected through approximately four synaptic levels of sensory-fugal processing. The modality-specific cortices at these four synaptic levels encode the most veridical representations of experience. Attentional, motivational and emotional modulations, including those related to working memory, novelty-seeking and mental imagery, become increasingly more pronounced within downstream components of unimodal areas, where they help to create a highly edited subjective version of the world. (ABSTRACT TRUNCATED)

Event-related patterns of 40-Hz EEG and heart rate: Memory load and motor programming

The present study investigated how the magnitude the word blindness suggestion effect on Stroop interference depended on hypnotic suggestibility when given as an imaginative suggestion (i.e. not post-hypnotic suggestion) and under conditions in which hypnosis was not mentioned. Hypnotic suggestibility is shown to be a significant predictor of the magnitude of the imaginative word blindness suggestion effect under these conditions. This is therefore the first study to show a linear relationship between the imaginative word blindness suggestion effect and hypnotic suggestibility across the whole hypnotizability spectrum. The results replicate previous findings showing that highs respond to the word blindness suggestion to a greater extent than lows but extend previous work by showing that the advantage for those higher on the hypnotizability spectrum occurs even in a non-hypnotic context. Negative attitudes about hypnosis may not explain the failure to observe similar effects of the word blindness suggestion in less hypnotizable individuals.

Dyslexia: a hundred years on

The first case of developmental dyslexia was reported by Pringle-Morgan in the BMJ on 7 November 1896.1 Pringle-Morgan, a general practitioner, and Hinshelwood, an ophthalmologist also writing at the turn of the century,2 speculated that such difficulties with reading and writing were due to “congenital word blindness,” and for many years the dominant view was that dyslexia was caused by visual processing deficiencies. There is still continuing interest in the role of visual factors in the aetiology of dyslexia, especially in low level impairments of the visual system.3 4 However, most research suggests that these are not its cause. The most widely accepted view today is that dyslexia is a verbal deficit5 and can be considered part of the continuum of language disorders. Indeed, converging evidence supports a specific theory, that dyslexic readers have phonological (speech) processing deficits. Dyslexia tends to runs in families, and the relatives …

A case of "pure" word blindness

A case of "pure" word blindness

Psychometric tests for assessment of brain function after solvent exposure.

Psychometric testing is a key issue in neuropsychological toxicology assessment. Evaluation of methods for assessing general intellectual impairment is necessary as conventional neurology has been shown to be insensitive to the neurotoxic effects of solvents and metals. This study presents an analysis of a psychometric test battery from an investigation of psycho-organic syndrome in a historical cohort of 96 metal degreasers with long-term exposure to solvents, particularly trichloroethylene. The neuropsychological test battery was a combination of Wechsler Adult Intelligence Scale (WAIS), Luria, and tests developed in Scandinavia. Linear regression analysis showed a significant dose-response relation between increasing cumulative solvent exposure and impaired psychometric test performance in 9 out of 15 tests. Multivariate analysis, however, suggests that much of the variance was due to confounding variables, especially age, and to a lesser degree, primary intellectual function and word blindness. After control for confounding factors the strongest association with solvent exposure occurred for the following three tests: acoustic-motor function, Paced Auditory Serial Addition Test (PASAT), and the visual gestalt test.

Dyslexia — Is It a Disease?

NEARLY a century has passed since the first published observation that some otherwise normally intelligent children have specific difficulty learning to read. The intervening years have seen both an intense search for the mechanism of this disorder and an ongoing debate about whether it exists. There have been a number of developments in this field since I last discussed these issues.1 The disorder was first termed "congenital word blindness" by British ophthalmologists, and for several decades it was assumed to be primarily visual. Then, in the 1930s, the American neurologist Samuel Orton called attention to the frequent association between reading . . .

Reviewing the Literature on Fernald's Technique of Remedial Reading.

BETWEEN THE TWO World ars, Grace Fernald developed a multisensory approach to teaching reading and spelling (VAKT) that united visual, auditory, kinesthetic, and tactile elements. Subsequently, this method has been much discussed and subjected to experimentation, for many people believe VAKT to be effective with learners who have failed to progress in reading under the usual methods, while others are doubtful. This article reviews Fer nald's theories and the literature concerning her method of teaching reading to disabled learners. The distinguishing feature of Fernald's technique is tracing. Like many teaching methods, tracing has been in use repeatedly for centuries. Sand tracing was used two thousand years ago in Roman schools, and the writings of Plato, Horace, and Sene ca mention use of kinesthetic and tactile stimuli (Irvine 1970). Word blindness, an inability to read, had also been recognized be fore Fernald, but little had been accomplished to correct the problem. Often, children and adults with this handicap were thought to be mental ly retarded or stubborn and were subsequently ignored. In developing a system to aid these nonreaders, Fernald wanted to fit the learning environment to the idio syncracies of each child. Observing that sometimes children could not

The advantages of being dyslexic

I am deeply honored to receive the award from The Orton Society, especially since it is in the name of Dr. Samuel Orton. He was a great man, and his work is still too little appreciated. In reviewing his writings I am constantly impressed with the meticulous care with which he studied each child, and by his creative imagination which permitted new insights into the causative mechanisms of language disabilities. Last year at the annual banquet of this Society I talked briefly about his theories in the light of current knowledge of how the brain works. At the risk of being repetitious I should like to recapitulate the general theme of his theory of cerebral dominance. You will recall that Dr. Orton studied a group of patients in whom letter and word reversals were an extremely prominent phenomenon. He coined a new term for these patients, and stated his theory about them as follows: I have offered the term strephosymbolia to define the cases of retardation of reading skills in which there can be demonstrated a confusion between dextrad and sinistrad orientation of letters; a tendency toward sinistrad reading of all or parts of words; and an unusual skill in mirror writing.I Somewhat similar cases had previously been described by Hinshelwood and others under the name of "word blindness." Dr. Hinshelwood had considered that this condition could be diagnosed only when there existed a very serious disorder of reading. Dr. Orton took exception to this approach, pointing out that there was a continuum of difficulty from the most severe to the least severe, and that, in fact, there was a tendency toward strephosymbolia in almost all children at some phase in the development of writing skills. Although Dr. Orton was careful to point out that there were many different forms of reading disability, it is clear that he considered "strephosymbolia" to be a major component in the overall problem. His explanation for this tendency toward distorted or backward writing was an ingenious one. He noted that all language functions are ordinarily

Word blindness with intact central visual fields. A case report.

Word blindness with intact central visual fields. A case report.

Varieties of alexia. Word and letter blindness.

Varieties of alexia. Word and letter blindness.

Language Disability

SCHOLASTIC failure is a common problem in every school and in all grades. Its etiologies are many, including: family attitudes, intelligence, motivation, physical defects, and emotional disorders. One of the common and least recognized causes of scholastic failure is language disability. 1,2 Language disability has been called word blindness, dyslexia, strephosymbolia, congenital alexia, and dysgraphia. When it is present, it can cause emotional maladjustment and underachievement or failure, and is a chronic handicap to the pupil. It has been said that as many as 10% to 15% of students have this handicap; and because of the anxieties and pressures caused by it in both the child and his family, it is imperative that physicians and teachers be well-informed about this condition. 3,4,5 Language involves all of the aspects of handling words: reading, writing, spelling, and speech. The range of ability runs from the child who reads at the age of

Learning Difficulties among Children of Normal Intelligence

failure, especially in the field of mental malfunction. Following the longestablished practice of the medical profession for avoiding embarrassment because of professional ignorance, we gave mysterious names to our problems. The neurologists helped us by offering as causes or explanations such items as congenital word blindness, caused by lesions in Broca's convolutions, and strephosymbolia or lack of unilateral brain domi-

Pure Word Blindness Considered as a Disturbance of Visual Space Perception [Abridged

Pure Word Blindness Considered as a Disturbance of Visual Space Perception [<i>Abridged</i>

Specific Dyslexia (Congenital Word Blindness): A Clinical and Genetic Study

Specific Dyslexia (Congenital Word Blindness): A Clinical and Genetic Study

Differential diagnosis of oligophrenia.

IN THE diagnosis of mental deficiency, dependent as it is not only on medical and psychological criteria but also on social standards, the defect must be distinguished from a considerable number of other conditions. These may conveniently be classified under the headings of intellectual defects of a less ominous nature, specific defects of a visual, auditory, or speech nature, and behavior defects in which the aberrant conduct is likely to be confused with mental defect. The following arrangement may serve to indicate the extent of these conditions: I. Intellectual defects Educational defectiveness Dullness Backwardness Specific defects Visual defects Blindness Visual cerebral injury Congenital word blindness Auditory defects Deaf-mutism High-tone deafness Congenital word deafness Speech defects Mutism Delayed development of speech Congenital motor aphasia Behavior defects Delinquency Maladjustment Adolescent instability

Agnostic Alexia without Agraphia Following Trauma

Agnostic alexia is an infrequent form of aphasia and is a variety of visual agnosia (mind blindness). It is a disturbance of language function consisting of failure of recognition of the conventional meaning of graphic symbols, and may include inability to read letters, syllables, words, musical notes, and mathematical figures. The terms alexia and word blindness, which are most frequently used for this con­ dition, are somewhat objectionable in that inability to read may depend on many differ­ ent focal cerebral defects. Agnostic alexia is more specific for it is used in contradis­ tinction to aphasie alexia and semantic alexia. In aphasie alexia there is loss of ability to comprehend statements of a simple character, the words being properly recog­ nized. In semantic alexia the patient is un­ able to comprehend complicated statements while retaining the ability to grasp simple ones. The act of seeing is a highly complicated procedure requiring the integrity of the optic apparatus and a considerable part of the cerebral cortex. Much of the mechanism of how it is accomplished is conjectural and controversial, and its study involves the fields of anatomy, physiology, and psychol­ ogyExperimental and clinical investigations have proved that the calcarine area (area 17 of Brodmann) of the occipital lobe is the site of the primary cortical termination of the visual impulse. Neurons from the retina maintain a precise spatial organization in their course to the external geniculate body and thence to the calcarine cortex, thereby producing point to point retinal representa-