1 / 42

Alexia and Agraphia: The Classic Picture

Alexia and Agraphia: The Classic Picture. ALEXIA IS THE ACQUIRED INABILITY TO COMPREHEND WRITTEN LANGUAGE. Classic Types of Alexia. 1) Alexia associated with sensory aphasia , usually associated with the dominant posterior temporal lobe.

victoria
Télécharger la présentation

Alexia and Agraphia: The Classic Picture

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Alexia and Agraphia: The Classic Picture ALEXIA IS THE ACQUIRED INABILITY TO COMPREHEND WRITTEN LANGUAGE Alexia & Agraphia

  2. Classic Types of Alexia • 1) Alexia associated with sensory aphasia, usually associated with the dominant posterior temporal lobe. • 2) Alexia with agraphia, usually associated with a lesion of the angular gyrus. • 3) Alexia without agraphia, also called pure agnosic alexia and usually associated with disruption of the splenium of the corpus callosum. • Associated Symptoms • Impaired ability to copy • Acalculia • Oral language normal (some mild anomia) • Writing and spelling normalish • Right homonymous hemianopsia • Occasional visual agnosia for colors and objects Alexia & Agraphia

  3. Alexia & Agraphia

  4. Classic Types of Alexia • 1) Alexia associated with sensory aphasia, usually associated with the dominant posterior temporal lobe. • 2) Alexia with agraphia, usually associated with a lesion of the angular gyrus. • 3) Alexia without agraphia, also called pure agnosic alexia and usually associated with disruption of the splenium of the corpus callosum. • Associated Symptoms • Impaired ability to copy • Acalculia • Oral language normal (some mild anomia) • Writing and spelling normalish • Right homonymous hemianopsia • Occasional visual agnosia for colors and objects Alexia & Agraphia

  5. Alexia & Agraphia

  6. Preliminary Comments: • Alexia without agraphia = pure word blindness = dyslexia without agraphia = agnosic dyslexia • This condition is characterized by a deficit in word reading, with a relative preservation of letter reading. Often there is a right homonymous hemianopsia and a color naming deficit. It is usually associated with damage of the left occipital lobe and the splenium of the corpus callosum. This suggests a disconnection between the left and right calcarine cortex and the left angular gyrus. • The patient is usually able to write spontaneously, but not read what has been written. Patients can often identify words spelled aurally. Number reading may be preserved. • The splenium is a posterior section of the corpus callosum with connects the right calcarine cortex with the left calcarine cortex (And vice-versa I suppose, though no clinical condition has emphasized this bilateral transfer of information). Alexia & Agraphia

  7. Alexia & Agraphia

  8. Preliminary Comments: • Alexia without agraphia = pure word blindness = dyslexia without agraphia = agnosic dyslexia • This condition is characterized by a deficit in word reading, with a relative preservation of letter reading. Often there is a right homonymous hemianopsia and a color naming deficit. It is usually associated with damage of the left occipital lobe and the splenium of the corpus callosum. This suggests a disconnection between the left and right calcarine cortex and the left angular gyrus. • The patient is usually able to write spontaneously, but not read what has been written. Patients can often identify words spelled aurally. Number reading may be preserved. • The splenium is a posterior section of the corpus callosum which connects the right calcarine cortex with the left calcarine cortex (And vice-versa I suppose, though no clinical condition has emphasized this bilateral transfer of information). Alexia & Agraphia

  9. Alexia & Agraphia

  10. AGRAPHIA • Several theorists have proposed that writing and reading, both superimposed on language, should be virtually identical. • Cases have great variance • There are always motor and linguistic components to be assessed in agraphia. • Neurological classifications: pure agraphia: foot of second frontal convolution (Exner's area), superior parietal lobe, posterior perisylvian region, left caudate and internal capsule aphasic agraphia (either graphemic deficits or agrammatic sentence structure) agraphia with alexia (parietal agraphia, poor graphemes, poor spelling) apraxic agraphia, grapheme production difficulties spatial agraphia (lesions of nondominant parietal lobe, horizontal line problems, left side neglect, intrusion of empty spaces) Alexia & Agraphia

  11. Two major distinctions: • Lexical, or orthographic, agraphia • Phonological agraphia. • Phonological agraphia: impaired ability to spell or write nonsense syllables and nonsense words • Clearly we do not just write by translating speech segments to orthographic units • Cases where they read a word by converting its meaning (picture of a mountain, to "m-o-u-n-t-a-i-n, that's mountain") • Deep dysgraphia: boat for yacht, smile for laugh • Patients report that they feel as if they are writing as though copying off an "internal screen.".. but may be relying on whole word Alexia & Agraphia

  12. Does Exner’s (1881) center exist? • Chedru, F., & Geshwind, N. (1972). Writing disturbances in acute confusional states. Neuropsychologia, 10, 343-354. • Pure agraphia is rare. • Lesion most often found in left frontal area (Exner’s (1881) writing center is at foot of left second frontal convolution) • Skepticism regarding such center: rarity, & authors had seen cases due to toxicity, reported cases often tumors and patients had more confusion • So they looked for it in acute confusional states • Looked at 34 acute confusional cases • 33/34 showed abnormality in writing • motor impairment • spatial disorders • reluctance to write • syntactical disorders • spelling and other linguistic disorders • So they conclude it is a multi-component task, easily disrupted by confusion Alexia & Agraphia

  13. Geshwind, N. & Fusillo, M. (1966). Color-naming defects in association with alexia. Archives of Neurology, 15, 137-146. • Two theories appear to have been proposed for color naming deficits: the first is an aphasic failure to name colors, and the second is a visual-disconnection syndrome. Patient here was previously described in Geshwind & Fuscillo (1964). The patient is described as a classic pure alexia without agraphia with marked color identification problems and right hemianopia. • Color perception was intact. Thus the problem was in matching color names to seen colors. The patient had infarction of the left calcarine cortex and the splenium of the corpus callosum. • Why is color naming intact? • Why is object naming and numbers not disturbed in these cases? Alexia & Agraphia

  14. Geshwind, N. & Fusillo, M. (1966). Color-naming defects in association with alexia. Archives of Neurology, 15, 137-146. • Two theories appear to have been proposed for color naming deficits: the first is an aphasic failure to name colors, and the second is a visual-disconnection syndrome. Patient here was previously described in Geshwind & Fuscillo (1964). The patient is described as a classic pure alexia without agraphia with marked color identification problems and right hemianopia. • Color perception was intact. Thus the problem was in matching color names to seen colors. The patient had infarction of the left calcarine cortex and the splenium of the corpus callosum. • Why is object naming and numbers not disturbed in these cases? Meyer (1905) proposed they stimulate tactile images further anterior. Alexia & Agraphia

  15. Benson, D. F., Brown, J., & Tomlinson, E. B. (1971). Varieties of alexia. Neurology, 21, 951-957. • Benson, Brown and Tomlinson (1971) present a series of six cases arguing for a functional and anatomical separation of word and letter alexia. The contrasting view would be that word and letter alexia are on a continuum, with letter alexia representing a more severe disorder. Cases 1 through 3 illustrate word alexia with relative sparing of letter reading and Cases 4 through 6 illustrate the opposite condition. • The first three cases represent alexia without agraphia. Two of the patients showed an initial hemiparesis and hemisensory loss. All three had difficulty reading with adequate writing. They had difficulty naming colors and were able to read letters but not words. This condition is consistently associated with damage to the dominant medial occipital region (usually resulting from an occlusion of the left posterior cerebral artery). • The second three cases originally suffered an acute non-fluent aphasia and right sided hemiparesis, with good comprehension. All three cases suggested inferior left frontal involvement. • Thus, there are two routes to reading illustrated by these cases. One route involves letter reading and the second is whole word reading. Alexia & Agraphia

  16. Benson, D. F., Brown, J., & Tomlinson, E. B. (1971). Varieties of alexia. Neurology, 21, 951-957. Alexia & Agraphia

  17. Benson, D. F., Brown, J., & Tomlinson, E. B. (1971). Varieties of alexia. Neurology, 21, 951-957. Alexia & Agraphia

  18. Benson, D. F., Brown, J., & Tomlinson, E. B. (1971). Varieties of alexia. Neurology, 21, 951-957. • Benson, Brown and Tomlinson (1971) present a series of six cases arguing for a functional and anatomical separation of word and letter alexia. The contrasting view would be that word and letter alexia are on a continuum, with letter alexia representing a more severe disorder. Cases 1 through 3 illustrate word alexia with relative sparing of letter reading and Cases 4 through 6 illustrate the opposite condition. • The first three cases represent alexia without agraphia. Two of the patients showed an initial hemiparesis and hem-isensory loss. All three had difficulty reading with adequate writing. They had difficulty naming colors and were able to read letters but not words. This condition is consistently associated with damage to the dominant medial occipital region (usually resulting from an occlusion of the left posterior cerebral artery). • The second three cases originally suffered an acute non-fluent aphasia and right sided hemiparesis, with good comprehension. All three cases suggested inferior left frontal involvement. • Thus, there are two routes to reading illustrated by these cases. One route involves letter reading and the second is whole word reading. Alexia & Agraphia

  19. Benson, D. F., Brown, J., & Tomlinson, E. B. (1971). Varieties of alexia. Neurology, 21, 951-957 • Thus, there are two routes to reading illustrated by these cases. One route involves letter reading and the second is whole word reading. BUT • WHY is letter reading preserved in alexia without agraphia? • Theory 1: Dejerine (pure word blindness): intact right visual cortex is separated from the intact left language cortex, because of splenic infarction. Normal writing and normal spelling of via aural route. (running fingers over letters, or eyes over letters improves reading) • Theory 2: Visual processing as a hierarchical system: letters are simpler. Alexia & Agraphia

  20. Can read words but not letters Pure Word Blindness Alexia without Agraphia Alexia with Agraphia Alexia & Agraphia

  21. Albert, M. L., Yamadori, A., Gardner, H., & Howes, D. (1973). Comprehension in alexia. Brain, 96, 317-328. • Notes Dejerine (1891, 1892) proposed two types of alexia: • Pure word blindness” preserved capacity to write resulting from damage to visual cortex of language dominant hemisphere and to the splenium. • .Alexia with agraphia: lesion of dominant angular gyrus. • This case is similar to a “third” type reported by Dejerine & Thomas (1904). : alexia with agraphia, with preserved ability to spell words aurally & to recognize aurally spelled words. He proposed it was due to a combination of pure word blindness with a separate lesion disconnecting left hand motor control from the language areas. • Albert et. al present this case to argue for a third type. • Patient had a tumor removed from left temporal-occipital region. • Poor reading, poor spelling, could not recognize word spelled aurally. Alexia & Agraphia

  22. THIS CASE Pure Word Blindness Alexia without Agraphia Alexia with Agraphia Alexia & Agraphia

  23. Albert, M. L., Yamadori, A., Gardner, H., & Howes, D. (1973). Comprehension in alexia. Brain, 96, 317-328. • Notes Dejerine (1891, 1892) proposed two types of alexia: • .Pure word blindness” preserved capacity to write resulting from damage to visual cortex of language dominant hemisphere and to the splenium. • .Alexia with agraphia: lesion of dominant angular gyrus. • This case is similar to a “third” type reported by Dejerine & Thomas (1904). : alexia with agraphia, with preserved ability to spell words aurally & to recognize aurally spelled words. He proposed it was due to a combination of pure word blindness with a separate lesion disconnecting left hand motor control from the language areas. • Albert et. al present this case to argue for a third type. • Patient had a tumor removed from left temporal-occipital region. • Poor reading, poor spelling, could not recognize word spelled aurally. Alexia & Agraphia

  24. Albert, M. L., Yamadori, A., Gardner, H., & Howes, D. (1973). Comprehension in alexia. Brain, 96, 317-328. • BUT: present, aurally or written, a word and then show three pictures, one accurate, one semantically similar, one phonetically similar. • e.g. apple: nipple, apple, orange • He had NO difficulty on this test. (so is this non-reading reading?) On the reverse form (show picture, pick written word) the patient could also choose the correct word --- but could not read it. • The patient could also choose the odd man out (by pointing), e.g. cat, dog, pig, wolf, hat. • Conclusion: the patient’s perception and semantic comprehension of written letters and words is intact. This continues within a broad semantic sphere. • Meaning without Reading? Alexia & Agraphia

  25. THIS CASE Pure Word Blindness Alexia without Agraphia Alexia with Agraphia Alexia & Agraphia

  26. Albert, M. L., Yamadori, A., Gardner, H., & Howes, D. (1973). Comprehension in alexia. Brain, 96, 317-328. • However, he had anomia. And could not easily provide the semantic category for pictures. • Thus, they propose this is a distinctive third form of alexia. • They propose a “partial” visual-motor and visual-auditory disconnection. BUT, the patient could point to correct written answers, even though he could not read them. • He retained his semantic reading ability, even though he lost his phonetic reading ability. • What’s the alternative – Missing Proposal???? Alexia & Agraphia

  27. Greenblatt, S. (1973). Alexia without agraphia or hemianopia: Anatomical analysis of an autopsied case. Brain, 96, 307-316. • Greenblatt notes a few cases of alexia without agraphia without a right hemianopsia. He notes that this is theoretically difficult to explain (the theories of Dejerine and Geshwind). The condition should result from a condition which isolates the angular gyrus from its pathways. This case showed problems with recent memory, a mild anomic aphasia, and severe dyslexia. Color naming, number reading, simple calculations, and writing were normal. There was no right homonymous hemianopia. • Upon autopsy the critical finding was a tumor which “appeared to originate in the inferomedial white matter of the left occipital lobe and spread in an anterior direction to involve the splenium of the corpus callosum. It hardly disturbed the primary visual cortex or its afferent optic radiation.” Thus this patient had an intact left calcarine cortex but the fibers connecting it to the angular gyrus were cut off. And the splenium was disconnected from the right occipital cortex to the angular gyrus. • Notes similarity between this case and the one by Ajax (1967). Alexia & Agraphia

  28. Yamadori, A. (1975). Ideogram reading in alexia. Brain, 98, 231-238. • 61-year old rh carpenter with left side cerebral vasculature problems • difficulty drawing, tried to light filter end without noticing, trouble putting on clothes, tended to prefer left hand, complained of being unable to read. • Japanese provides both Kanji (Chinese ideograms) and Kana (Chinese phonograms) • Patient could read Kanji -- but not Kana (left hemisphere?) • Patient, when writing with the left hand, produced mirror images of Kanji Alexia & Agraphia

  29. Lhermitte, F. & Beauvois, M. F. (1973). A visual-speech disconnexion syndrome: Report of a case with optic aphasia, agnosia, alexia, and colour agnosia. Brain, 96, 695-714. • Notes Freund case with left parietal-occipital, possibly callosal, tumor in which objects could be identified tactually, but not visually. There was also a right homonymous hemianopsia and aphasia. Freund called it “optic aphasia.” He proposed damage to the left optic radiations and the associative fibers between the right occipital area and the left speech areas. He did not distinguish between optic agnosia and this condition, which he considered a form of aphasia. Freud (1891) criticized this. • This case is purportedly not a case of optic agnosia nor a case of optic aphasia. They call it a visual-speech disconnection. • Errors in naming pictures & objects (30% of about 600) but could pantomime use correctly. People correctly identified but naming pictures of famous faces was bad. • Spontaneous drawings and writing okay. Copying poor. • Could read a few letters, no syllables or words. • Only 4% errors in naming 100 objects from descriptions. About 10% presented tactually. [so it’s not aphasia] • Color matching ok, color naming poor. Was also poor at coloring objects (with expected color). • Use the pictures. He misnamed picture. Drew from memory but misnamed. Then to command drew, correctly, both the correct object and the misnamed object. Alexia & Agraphia

  30. Lhermitte, F. & Beauvois, M. F. (1973). A visual-speech disconnexion syndrome: Report of a case with optic aphasia, agnosia, alexia, and colour agnosia. Brain, 96, 695-714. Alexia & Agraphia

  31. Lhermitte, F. & Beauvois, M. F. (1973). A visual-speech disconnexion syndrome: Report of a case with optic aphasia, agnosia, alexia, and colour agnosia. Brain, 96, 695-714. Alexia & Agraphia

  32. Lhermitte, F. & Beauvois, M. F. (1973). A visual-speech disconnexion syndrome: Report of a case with optic aphasia, agnosia, alexia, and colour agnosia. Brain, 96, 695-714. Alexia & Agraphia

  33. Lhermitte, F. & Beauvois, M. F. (1973). A visual-speech disconnexion syndrome: Report of a case with optic aphasia, agnosia, alexia, and colour agnosia. Brain, 96, 695-714. Alexia & Agraphia

  34. Lhermitte, F. & Beauvois, M. F. (1973). A visual-speech disconnexion syndrome: Report of a case with optic aphasia, agnosia, alexia, and colour agnosia. Brain, 96, 695-714. • Proposes its a disconnection syndrome. Does this give the high incidence of semantic errors in object naming? The semantically similar spread suggests something got through. Ex. For a box: “it’s a small case, it’s a suit case. . . it’s a drawer, it’s a pen box perhaps.” [This is all physically similar, and semantically related. The patient did not propose it was a house] The authors propose that an “imprecise elaboration of the visual-speech message or a disturbance en route to the temporal region could account for a defective selection of the adequate word and for a less differentiated and more extensive activation of the semantic field. [But morphological errors were fewer and disappeared when multiple exemplars of a semantic category were presented. This suggests that it could not be simply a limited transfer of a poor representation of the physical attributes of the object - or more morphological errors would be made. It must have gotten to the correct semantic network. If single physical features stimulated the semantic network it seems that they would stimulate others (thought the stimuli were not designed to contrast this. So, it must be that it got to a malfunctioning network. Is this a disconnection?] Alexia & Agraphia

  35. Lhermitte, F. & Beauvois, M. F. (1973). A visual-speech disconnexion syndrome: Report of a case with optic aphasia, agnosia, alexia, and colour agnosia. Brain, 96, 695-714. • The route to correct words was a mixture of semantic errors, perseverations and the use of morphological features. E.G. In response to pictures of objects • To a cup: (the preceding stimulus, a cork screw, had been rightly named) “the cork screw too. . . there is a porcelain handle. . . or a fancy cork. . . there is the reflection. . . then I should see only a cork unless it could be a cup.” • To a bus: “A wagon. . . public transport since there is a back door. . . a stage coach. . . it would be. . . no. . . a city cab. . . not a cab but a city bus.” • [this sounds like the correct supracategory is stimulated and then features are compared to choose the subcategory. Or all subcategories are equally aroused and the patient has to contrast features in order to choose amongst them. Would this happen if only partial stimuli were sent? The “back door” was quickly identified but then the patient said a “cab” which does not have a back door. So that doesn’t seem like it was a partial image. An analysis of the examples provided by the authors seems to support this in other cases also... the aquarium is first identified as a bird cage, which is a container for pets - a high level semantic category, then the features are analyzed and the correct answer is derived. When perseverations occur this leads the patient astray. The details which are used suggests access. Is the access serial?] • They challenge Geshwind’s proposal that it is a callosal disconnection with reference to Rubens and Benson’s (1971) patient who could not group objects by category, only by morphology. And it can not explain why the same patient could read large, but not small, letters [do they eye-trace it?] Alexia & Agraphia

  36. Ajax, E. T., Schenkenberg, T., & Kasteljanetz, M. (1977). Alexia without agraphia and the inferior splenium. Neurology, 27, 685-688. • Reports on a case of alexia without agraphia with damage to the inferior splenium. Extensive infarction of the left occipital lobe, the inferior one third of the left forceps major, and contiguous splenium of the corpus callosum. This supports observations made by Greenblatt & Cummings et al. It is clear that damage to the left occipital lobe and the splenium are involved. But why are color naming and a right homonymous hemianopia are not always present. • Greenblatt’s patient had left occipital and exhibited alexia without agraphia WITHOUT a color naming deficit. The patient had damage to inferior outflow tracts of left visual cortex and the splenium. The current report suggests that color naming can be accomplished through the dorsal (superior) elements of the splenium. In this case only the inferior third of the splenium was destroyed. Thus the remaining one third are sufficient for color naming. • But most patients have remaining reading ability – so remaining fibers, or more anterior fibers must be useful. • So this patient should not have been bothered by the Stroop effect. Alexia & Agraphia

  37. Deep Dyslexia • Whole word recognition for meaning, not phonology or form • Derivational • running -- runner • Length -- long • Semantically paralexic • rock --- stone • house -- home • listen --- quiet • lake --- pond Alexia & Agraphia

  38. Deficit in sounding out (difficulty reading non-words • Yet can “access” complex words • yacht --- boat • sword --- dagger • Can read Case mixed words: • CaTtlE • Or rearranged: show Alexia & Agraphia

  39. So they have good orthographic skills • Usual proposal (e.g., Coltheart) : remaining right hemisphere connotative, semantic information may be available • But right hemisphere reading in split brain patients is not as seen in deep dyslexia • Very weak normal studies with dichotically presented words Alexia & Agraphia

  40. Early cases reported by Marianne Simmel • Murderer: multiple languages • Woman • Reichstag ---- Berlin • She saw herself sitting on a park bench in front of government buildings • So: What if it is not accessing RH semantic stores, but right hemisphere imagery? Alexia & Agraphia

  41. Hillis, A. E., B. C. Rapp, et al. (1999). "When a rose is a rose in speech but a tulip in writing." Cortex35: 337-356 RCM’s Error Rates (#Errors/Total ´ 100) and Types in Selected Tasks in Study 1 Alexia & Agraphia

  42. Hillis, A. E., B. C. Rapp, et al. (1999). "When a rose is a rose in speech but a tulip in writing." Cortex35: 337-356 • Her 16 errors in written naming were predominantly (13/16; or 81%) semantic errors, such as • eagle = owl • bus = airplane • Her remaining errors were: one unrelated word or visual Error • barn = lunch box • one semantically and orthographically/phonologically related word • watch = watchful • and one nonword • zebra = jephrys Deep Dyslexia Case Alexia & Agraphia

More Related