-
Language, Speech, and Hearing Services... Oct 2018The purpose of this tutorial is to discuss the language basis of dyslexia in the context of developmental language disorders (DLDs). Whereas most studies have focused on... (Review)
Review
PURPOSE
The purpose of this tutorial is to discuss the language basis of dyslexia in the context of developmental language disorders (DLDs). Whereas most studies have focused on the phonological skills of children with dyslexia, we bring attention to broader language skills.
METHOD
We conducted a focused literature review on the language basis of dyslexia from historical and theoretical perspectives with a special emphasis on the relation between dyslexia and DLD and on the development of broader language skills (e.g., vocabulary, syntax, and discourse) before and after the identification of dyslexia.
RESULTS
We present clinically relevant information on the history of dyslexia as a language-based disorder, the operational definitions used to diagnose dyslexia in research and practice, the relation between dyslexia and DLD, and the language abilities of children with dyslexia.
CONCLUSIONS
We discuss 3 clinical implications for working with children with dyslexia in school settings: (a) Children with dyslexia-with and without comorbid DLDs-often have language deficits outside the phonological domain; (b) intervention should target a child's strengths and weaknesses relative to reading outcomes, regardless of diagnostic labels; and (c) those who have dyslexia, regardless of language abilities at the time of diagnosis, may be at risk for slower language acquisition across their lifetime. Longitudinal studies are needed to assess multiple language skills early, at the time of the diagnosis of dyslexia, and years later to better understand the complex development of language and reading in children with dyslexia.
Topics: Child; Child Language; Child, Preschool; Dyslexia; Humans; Language Development Disorders; Language Tests; Language Therapy
PubMed: 30458538
DOI: 10.1044/2018_LSHSS-DYSLC-18-0049 -
Rinsho Shinkeigaku = Clinical Neurology Aug 2011The author reviews the lesion localization of non-aphasic alexia and agraphia and proposes a new classification of alexia and agraphia on this basis. The newly proposed... (Review)
Review
The author reviews the lesion localization of non-aphasic alexia and agraphia and proposes a new classification of alexia and agraphia on this basis. The newly proposed alexia and agraphia are pure alexia for kana (Japanese phonograms), or more generally pure alexia for letters, caused by a lesion in the posterior occipital area (posterior fusiform/inferior occipital gyri), and pure agraphia for kanji (Japanese morphograms) caused by a lesion in the posterior middle temporal gyrus and also a lesion restricted to the angular gyrus. In addition, the anatomical lesions presumably responsible for the parietal apraxic agraphia, frontal pure agraphia and thalamic agraphia are discussed.
Topics: Agraphia; Dyslexia; Humans; Occipital Lobe; Temporal Lobe
PubMed: 21878722
DOI: 10.5692/clinicalneurol.51.567 -
Archives of Neurology Jun 1977A variety of alexia has been demonstrated that can be distinguished from the two classically recognized types of alexia. This reading disorder is seen in patients with a...
A variety of alexia has been demonstrated that can be distinguished from the two classically recognized types of alexia. This reading disorder is seen in patients with a dominant frontal lobe pathologic condition that has produced a motor language disturbance (Broca aphasia) and is sufficiently disabling to deserve consideration as a variety of alexia. Functionally, the frontal reading disturbance differs from the other two types in that the patient comprehends meaningful content words better than relational or syntactic structures. Four factors that may underly frontal alexia have been noted: (1) gaze paresis, (2) inability to maintain verbal sequences; (3) inability to comprehend syntactic structure, and (4) literal alexia.
Topics: Agraphia; Aphasia; Dyslexia, Acquired; Hemiplegia; Humans; Visual Fields
PubMed: 860935
DOI: 10.1001/archneur.1977.00500180021004 -
Revue Neurologique May 2008Alexia without agraphia is the result of a left inferotemporal cortical lesion. This unilateral lesion provokes an almost irrecoverable word reading disability. This... (Review)
Review
Alexia without agraphia is the result of a left inferotemporal cortical lesion. This unilateral lesion provokes an almost irrecoverable word reading disability. This anatomical-clinical observation has identified as crucial an area on the left fusiform gyrus, which represents a sort of "letter cranial bump". This area, located near the left V4, has been labeled the visual word form area (VWFA). The VWFA ensures visual word processing whatever the visual field stimulated. In normal subjects, imaging methods show an activation of the VWFA during reading. In patients, the alexia that follows a VWFA lesion proves that this area is an essential relay for cerebral word reading processing. Therefore, pure alexia is no longer explained by a posterior interhemispheric disconnection.
Topics: Agraphia; Dyslexia; History, 20th Century; Humans; Magnetic Resonance Imaging; Reading; Temporal Lobe; Visual Cortex; Visual Fields
PubMed: 18675050
DOI: 10.1016/S0035-3787(08)73294-6 -
Current Opinion in Neurology Aug 2006To discuss whether recent functional neuroimaging results can account for clinical phenomenology in visual associative agnosias. (Review)
Review
PURPOSE OF REVIEW
To discuss whether recent functional neuroimaging results can account for clinical phenomenology in visual associative agnosias.
RECENT FINDINGS
Functional neuroimaging studies in healthy human subjects have identified only two regions of ventral occipitotemporal cortex that invariantly respond to individual faces and visual words, respectively. The signature of face identity coding in the fusiform neural response was shown to be missing in a patient with prosopagnosia. Another case study established that a surgical lesion close to the region sensitive to visual words can result in pure alexia.
SUMMARY
Evidence is increasing that functional specialization for processing face identity and visual word forms is restricted to two specialized sensory modules in the occipitotemporal cortex. A structural or functional lesion to face-sensitive and word-sensitive regions in the ventral occipitotemporal cortex can provide the most parsimonious account for the clinical syndromes of prosopagnosia and agnosic alexia. This review suggests that functional specialization should be considered in terms of whether exclusively one brain region (instead of many) underpins a defined function and not as whether this brain region underpins exclusively one cognitive function. Such functional specialization seems to exist for at least two higher-order visual perceptual functions, face and word identification.
Topics: Dyslexia; Humans; Magnetic Resonance Imaging; Prosopagnosia; Reading; Recognition, Psychology
PubMed: 16914978
DOI: 10.1097/01.wco.0000236619.89710.ee -
Neurologia I Neurochirurgia Polska 1972
Topics: Adult; Angiography; Carotid Arteries; Cognition Disorders; Color Perception; Dyslexia, Acquired; Electroencephalography; Humans; Male; Vision Disorders
PubMed: 5032300
DOI: No ID Found -
Handbook of Clinical Neurology 2013Developmental dyslexia (DD) is a specific and persistent disability affecting the acquisition of written language. Prevalence is estimated to be between 5% and 17% of... (Review)
Review
Developmental dyslexia (DD) is a specific and persistent disability affecting the acquisition of written language. Prevalence is estimated to be between 5% and 17% of school-aged children; it therefore represents a major public health issue. Neurological in origin, its causes are unknown, although there is a clear genetic component. Diagnosis rests upon the use of standardized tests and tools to assess reading and spelling, as well as phonological skills. The importance of early diagnosis cannot be overemphasized and much current research is focusing on screening and prediction, particularly through use of objective imaging techniques (e.g., EEG/MEG), which have implicated cortical abnormalities in central auditory processing (Giraud et al., 2005, 2008). Remediation should be intensive, begin as early as possible, and be tailored to the individual. Phonics based treatments are most effective and several variants, incorporating temporal auditory, articulatory, or multisensory training exercises, have been developed or proposed. Clinical improvements in phonological skills and reading with such treatments have been shown to correlate with changes in the brains of dyslexic children in several functional imaging studies.
Topics: Dyslexia; Humans
PubMed: 23622168
DOI: 10.1016/B978-0-444-52891-9.00023-3 -
Brain : a Journal of Neurology Jun 1983A 77-year-old composer had a left occipital lobe haemorrhagic infarct giving a severe reading disturbance with well-preserved writing and without appreciable aphasia. He...
A 77-year-old composer had a left occipital lobe haemorrhagic infarct giving a severe reading disturbance with well-preserved writing and without appreciable aphasia. He continued to read music and to compose. His text- and music-reading performance under different conditions suggests that this unusual dissociation was primarily due to four factors. (1) He was unusually talented musically and inferred a great deal about the music he was reading. (2) The symbols of staff music notation are more visually distinctive than the symbols of phonetic language writing systems. (3) In staff music notation, pitch is represented ordinally, and other symbols are also distinguishable by their relative positions and sizes. (4) Music notation can be usefully read by interpreting it acoustically, kinaesthetically or in terms of formal musical concepts; in contrast to written language, it need not be interpreted referentially or in terms of auditory-verbal images. His disorder fits the classic visual-verbal disconnection account of alexia without agraphia and the contemporary view that music involves a family of related but distinct skills probably involving many brain areas in both hemispheres, although different cortical areas make characteristic contributions to different musical behaviours.
Topics: Aged; Agraphia; Dyslexia, Acquired; Humans; Male; Music
PubMed: 6850277
DOI: 10.1093/brain/106.2.435 -
Journal of Neurology, Neurosurgery, and... Dec 2003
Topics: Adult; Child; Dyslexia; Humans
PubMed: 14638872
DOI: 10.1136/jnnp.74.12.1603 -
Journal of Neurology, Neurosurgery, and... Apr 1986A 59-year-old, right-handed, college-educated male examined after stroke presented spelling alexia with relative sparing of writing. He was not aphasic. A striking...
A 59-year-old, right-handed, college-educated male examined after stroke presented spelling alexia with relative sparing of writing. He was not aphasic. A striking feature of the alexia was preserved recognition of letters printed in view by the clinician. He was able to read words through letter-by-letter oral spelling when letters were presented in this dynamic fashion. We describe this as a dynamic form of spelling alexia. Head CT scan showed a large left hemisphere posterior lesion infringing on the corpus callosum, and a right hemisphere opercular lesion. We suggest that sparing of the right parietal-occipital cortex may contribute to the remarkable sparing of dynamic letter reading.
Topics: Cerebral Cortex; Cerebral Infarction; Dyslexia, Acquired; Humans; Male; Middle Aged; Neuropsychological Tests; Tomography, X-Ray Computed
PubMed: 3701357
DOI: 10.1136/jnnp.49.4.455