Language disorders


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Language disorders

  1. 1. Aphasia, Alexia, Agraphia and Disconnection Disorders William Wallis
  2. 2. Some Definitions <ul><li>Aphasia : an acquired loss or impairment of language function caused by brain disease or dysfunction </li></ul><ul><li>Alexia : loss or impairment of the ability to comprehend language in written or printed form caused by brain disease or dysfunction </li></ul><ul><li>Agraphia : loss or impairment of the ability to express language in written or printed form caused by brain disease or dysfunction </li></ul>
  3. 3. Historical Notes <ul><li>The aphasias represent among the earliest evidence of anatomical localisation </li></ul><ul><li>Phrenology provided the conceptual, if erroneous background ( Gall ) </li></ul>
  4. 4. Historical Notes <ul><li>Broca (1861-1865 ) Wernicke (1874) </li></ul>
  5. 5. Historical Notes <ul><li>Interest in aphasia languished in the 20 th Century till revitalised by Geschwind 1960’s </li></ul><ul><li>Modern imaging has confirmed much of the classical work of the 19 th Century European neurologists </li></ul>
  6. 6. Some General Comments about Aphasia and Similar disorders <ul><li>Language, speech, and thought are variously described by the interests of those defining the terms </li></ul><ul><li>For most neurologists these disorders are phenomena used to locate and identify the nature of the underlying brain disorder </li></ul><ul><li>The site of the lesion does not necessarily indicate that this is where that function resides in a normal brain. The term “ language centre ” is unsophisticated. Rather, the lesion has disrupted the function in question </li></ul>
  7. 7. Some General Comments about Aphasia and Similar disorders <ul><li>Clinical phenomenology can generally predict the site of the lesion; but lesions in the areas in question may occasionally be asymptomatic. Furthermore, lesions outside of the expected area may produce an unexpected language disorder. </li></ul><ul><li>Handedness, age, the evolution of the disease, and prior brain disease may explain part, but not all, of the above variability </li></ul>
  8. 8. Some General Comments about Aphasia and Similar disorders <ul><li>Dominance for language . 95-99% right-handed people have L cerebral dominance. There are neuroanatomical differences between R and L handedness </li></ul><ul><li>Non-right handed people have 60% left and 40% right cerebral dominance. They are more likely to develop aphasia from any brain disorder but also recover better </li></ul><ul><li>Age . Children have equipotent dominance and recover from aphasia better than adults </li></ul><ul><li>Crossed aphasia. ( R-handed aphasic with R cerebral lesion) often associated with prior brain injury </li></ul>
  9. 9. Some General Comments about Aphasia and Similar disorders <ul><li>Recovery from aphasia may continue for longer than recovery from other </li></ul><ul><li>Persistent Mutism is rare in aphasics </li></ul><ul><li>Spoken and written language should be similarly affected in most forms of aphasia </li></ul><ul><li>Although any form of brain disease can cause aphasia, stroke is the most common </li></ul>
  10. 10. Anatomical Localisation in Aphasia <ul><li>Usually cortical and in middle cerebral artery distribution ( perisylvian ). These regions represent “ cortical projection areas” </li></ul><ul><li>Non-fluent aphasia = anterior to central sulcus </li></ul><ul><li>Fluent aphasia = posterior to central sulcus </li></ul>
  11. 11. Connections of “Speech Areas” Arcuate fasciculus and corpus callosum
  12. 12. Anatomical Localisation in Aphasia the Importance of Repetition <ul><li>Perisylvian area lesions = impair repetition </li></ul><ul><li>Arcuate fasciculus lesions = impair repetition </li></ul><ul><li>Border zone areas, around perisylvian cortex.= repetition may be relatively spared </li></ul>
  13. 13. Some Forms of Aphasia <ul><li>Perisylvian Aphasias </li></ul><ul><li>Broca’s aka non-fluent, expressive, motor </li></ul><ul><li>Wernicke’s aka fluent, receptive, sensory </li></ul><ul><li>Global: aka total, mixed </li></ul><ul><li>Conduction subcortical disconnection </li></ul><ul><li>Border zone Aphasias </li></ul><ul><li>Transcortical </li></ul>
  14. 14. Useful Clinical Findings in aphasia <ul><li>Conversational speech </li></ul><ul><li>Comprehension spoke language </li></ul><ul><li>Repetition of spoken language </li></ul><ul><li>Confrontational naming </li></ul><ul><li>Reading: Both Aloud and Comprehension </li></ul><ul><li>Writing </li></ul><ul><li>Associated findings </li></ul>
  15. 15. Broca’s Aphasia 2 nd & 3 rd frontal convolutions <ul><li>Fluency </li></ul><ul><li>Comprehension spoke language: </li></ul><ul><li>Repetition of spoken language </li></ul><ul><li>Confrontational naming </li></ul><ul><li>Reading: Aloud </li></ul><ul><li>Comprehension </li></ul><ul><li>Writing </li></ul><ul><li>Associated findings </li></ul>
  16. 16. Wernicke’s Aphasia Posterior 3 rd superior temporal gyrus <ul><li>Conversational speech </li></ul><ul><li>Comprehension spoke language </li></ul><ul><li>Repetition of spoken language </li></ul><ul><li>Confrontational naming </li></ul><ul><li>Reading: Aloud </li></ul><ul><li>Comprehension </li></ul><ul><li>Writing </li></ul><ul><li>Associated findings </li></ul>
  17. 17. Conduction Aphasia subcortical and suprasylvian <ul><li>Conversational speech </li></ul><ul><li>Comprehension spoke language </li></ul><ul><li>Repetition of spoken language </li></ul><ul><li>Confrontational naming </li></ul><ul><li>Reading: Aloud </li></ul><ul><li>Comprehension </li></ul><ul><li>Writing </li></ul><ul><li>Associated findings </li></ul>
  18. 18. Transcortical Aphasia Border zone or Perisylvian <ul><li>Conversational speech </li></ul><ul><li>Comprehension spoke language </li></ul><ul><li>Repetition of spoken language </li></ul><ul><li>Confrontational naming </li></ul><ul><li>Reading: Aloud </li></ul><ul><li>Comprehension </li></ul><ul><li>Writing </li></ul><ul><li>Associated findings </li></ul>
  19. 19. Some Special Causes of Aphasia and the Imitators of Aphasia <ul><li>Migraine </li></ul><ul><li>Primary progressive aphasia </li></ul><ul><li>Landau-Kleffner Syndrome. Ictal and postictal epileptiform events </li></ul><ul><li>Herpes Simplex </li></ul><ul><li>******** </li></ul><ul><li>Mutism </li></ul><ul><li>Foreign Accent Syndrome </li></ul>
  20. 20. Disconnection Syndromes <ul><li>Lesions sparing the classical cortical speech areas but producing language disorders by “disconnecting” eloquent parts of the brain from each other and preventing their concerted action </li></ul><ul><li>Connections include: </li></ul><ul><li>1. Arcuate fasciculus </li></ul><ul><li>2. Isolation of dominant perisylvian areas </li></ul><ul><li>3. Corpus callosum </li></ul>
  21. 21. Disconnection Syndromes <ul><li>1.Conduction aphasia </li></ul><ul><li>2.Transcortical aphasia </li></ul><ul><li>3. Alexia without agraphia </li></ul>
  22. 22. Transcortical Aphasia A B When the regions of Broca, Wernicke and the arcuate fasciculus are intact (A), but surrounded by adjacent lesions (B), they are disconnected or isolated from their projection inputs. This results in various forms of aphasia, because of a disconnection from outside projections ( or area of concepts ) into A . The capacity to repeat, however, is relatively well preserved, as A is intact
  23. 23. Alexia without Agraphia The Ultimate Disconnection Syndrome Predict the Clinical Findings and Explain
  24. 24. Alexia without Agraphia 1 Right homonymous hemianopia Not aphasic and can write, as perisylvian area intact Cannot read as intact right occipital lobe is disconnected from dominant hemisphere by lesion in splenium of corpus callosum Relevant areas are supplied by posterior communicating artery Not to be confused with alexia and agraphia (usually angular gyrus lesion)
  25. 25. A Summary Alexia without agraphia Combination of a cortical lesion and a subcortical disconnection 1 Aphasias from lesions in projection cortex (Broca’s and Wernicke’s regions) Aphasia from subcortical disconnection or conduction aphasia Alexia with agraphia: lesion in angular gyrus or association cortex Transcortical aphasia isolates Broca’s and Wernicke’s regions and their connection