Alexia
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| ICD-10 | R480 | |
|---|---|---|
| ICD-9 | 315.01, 784.61 | |
| OMIM | [1] | |
| DiseasesDB | [2] | |
| MedlinePlus | [3] | |
| eMedicine | / | |
| MeSH | {{{MeshNumber}}} | |
Alexia (from the Greek ἀ, privative, expressing negation, and λέξις = "word") is an acquired type of sensory aphasia where damage to the brain causes a patient to lose the ability to read. It is also called word blindness, text blindness or visual aphasia.
Contents |
[edit] Causes
Alexia typically occurs following damage to the left hemisphere of the brain or to the areas of the occipital and temporal lobes, which are responsible for processing auditory, phonological and visual aspects of language. The region at the junction of occipital and temporal lobes (sometimes called the occipito-temporal junction) coordinates information that is gathered from visual and auditory processing and assigns meaning to the stimulus. Alexia can also occur following damage to the inferior frontal lobe, especially Broca's area. Damage to these different areas cortex result in somewhat different patterns of difficulty in affected individuals.
[edit] Presentation
Alexia may be accompanied by expressive and/or receptive aphasia (the inability to produce or comprehend spoken language). Alexia can also co-occur with agraphia, the specific loss of the ability to produce written language even when other manual motor abilities are intact. In other cases, damage is restricted to areas responsible for input processing. The result is known as alexia without agraphia. In this scenario, an individual's ability to produce written language is spared even though they are unable to understand written text.
Alexia without agraphia results from a left occipital splenium of the corpus callosum lesion.
[edit] See also
[edit] References & Bibliography
[edit] Key texts
[edit] Books
[edit] Papers
- Mayall, K. A. & Humphreys, G. W. (1996). Covert recognition in a connectionist model of pure alexia. In J. A. Reggia, E. Ruppin & R. Berndt (Eds.), Neural modelling of brain and cognitive disorders: Progress in Neural Networks. New York: World Scientific.
- Mayall, K. A. & Humphreys, G. W. (1996). A connectionist model of alexia: Covert recognition and case mixing effects. British Journal of Psychology, 87, 355-402.
- Price, C. J. & Humphreys, G. W. (1995) Contrasting effects of letter spacing in alexia: Further evidence that different strategies generate word length effects in reading. Quarterly Journal of Experimental Psychology, 48A, 573-597.
[edit] Additional material
[edit] Books
[edit] Papers
Francis, D., Riddoch, M. J. & Humphreys, G. W. (2001) Treating agnosic alexia complicated by additional impairments. Neuropsychological Rehabilitation, 11, 113-145
- Mayall, K. A. & Humphreys, G. W. (1992). A connectionist model of pure alexia. In I. Aleksander & J. Taylor (Eds.), Artificial Neural Networks 2. Amsterdam: Elsevier Science.
[edit] External links
| This page uses content from the English-language version of Wikipedia. The original article was at Alexia. The list of authors can be seen in the page history. As with Psychology Wiki, the text of Wikipedia is available under the GNU Free Documentation License. |
