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Aphasia and Cognitive Science

Aphasia and Cognitive Science. Swathi Kiran Communication Sciences & Disorders University of Texas at Austin s-kiran@mail.utexas.edu. Stages of speech production. What is aphasia? 1. Acquired versus developmental 2. Language versus Speech

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Aphasia and Cognitive Science

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  1. Aphasia and Cognitive Science Swathi Kiran Communication Sciences & Disorders University of Texas at Austin s-kiran@mail.utexas.edu

  2. Stages of speech production

  3. What is aphasia? • 1. Acquired versus developmental • 2. Language versus Speech • 3. Language versus involvement of other Cognitive Processes • 4. Results from brain damage

  4. Etiologies of aphasia 1. CVA: Cerebrovascular accident or stroke • 1. Ischemic strokes • 2. Hemorrhage 2. Aneurysm 3. Tumor 4. Trauma 5. Unknown Etiology

  5. Language Areas: • Broca’s area (44, 45) • Wernicke’s area • Inferior parietal lobule • Angular gyrus • Supramarginal gyrus • Dorsolateral prefrontal cortex • Insula • Supplementary motor area

  6. www.stroke.org

  7. Cerebral hemorrhage: tissue necrosis Cerebral infarct Cerebral hemorrhage

  8. Cerebral infarct Cerebral hemorhage Multiple infarct

  9. Major signs of aphasia: Naming • difficulties also seen in dementia. • This incorrect substitution is called a paraphasia • Semantic paraphasia: if the word is related in meaning • Target word Response • Stethoscope Telescope • Phonemic paraphasia substituting some other sounds: • Paper Paker • Neologistic paraphasia: complete novel word which does not exist in that language • Chicken Barnett

  10. Nonfluent aphasia Pt: Yeah.. wendesday…paul and dad.. hospital.. yeah…doctors, two and teeth • Absence of word combinations • No pronouns • Verbs are lacking • Patients more often block on the initial sound of the word • These patients present with articulatory disturbances although the phonological target may be retrieved the word is still unintelligible • Often see a dissociation between oral and written naming in these patients • Partial preservation of written word finding

  11. Fluent aphasia • Well all I know is somebody is clipping the knoples and some one someone have of the kenepung aim why I don’t know • I gave him a God! I know it, Why can’t I say it? • He is falling of the t.. t.. t.. anyhow, the mother is sti..sti. she .. the water is falling over the fink… fink…stink…sink… • Havent been around there at all since we got in to this time here, anything about here.. only because we had to do that, and then she got back with it… • Intact grammatical framework • Inability to retrieve nouns and adjectives • Pure morphological words intact (pronouns, prepositions, copulas, auxiliary and modal verbs) • Substitutions of vague, indefinite words such as “thing” • Circumlocutions • Erroneous words or neologisms

  12. Repetition: • Damage to the perisylvian region • Comprehension deficit: • Can be impaired to variable degrees. • Grammatical processing • Difficulty generating sentences into which the words have specific slots. • Reading and writing: • Alexia with agraphia: presence of both reading and writing impairments, usually with Wernicke’s or transcortical sensory aphasia. • Alexia without agraphia: separate condition by itself in the presence of fluent, spontaneous speech and good comprehension

  13. Types of aphasia • Broca’s Aphasia • Production: • Nonfluent, mute, sparse output, effortful speech • Telegraphic speech • Nouns are easier than verbs • Selective deletion of functor words and abnormal word order • Use of simple sentences more than complex • Use of over learned stereotypical utterances • Flat melodic contour • Naming impaired • Auditory comprehension relatively spared • Non fluent aphasia

  14. Wernicke’s aphasia • Production • Fluent, normal prosody • Paraphasic output • Impaired naming: verbal and literal paraphasias • Lacking in content • No self corrections • Naming is a major deficit • Problems in auditory comprehension • Inability to repeat

  15. Conduction Aphasia • Production • Fluent spontaneous output • Difficulty in phonological selection • Impaired naming • Repetition • Severely impaired, most common repetition with phonemic paraphasia • Often omit or substitute words • In repetition, multisyllabic words are more difficult

  16. Global Aphasia • Production • Can be fluent or nonfluent • Severe deficit crossing all language modalities • Can gesture well • Repetition • Impaired • Auditory Comprehension severely impaired • All aspects of language are impaired

  17. Naming

  18. Activation of network of features • Influenced by frequency, imageability, animacy Semantic representation • Sequential: 2 stages (Levelt, 1989) • Interactive: Bi-directional links (Dell, 1986) Activation of corresponding address or Activation of potential nodes Phonological representation Phoneme level Framework for lexical access

  19. Interactive activation model

  20. A Neural network model of lexical processing Plaut, 1996

  21. Rapp & Goldrick, 2000

  22. Rehabilitation of aphasia

  23. Treatment for patients with aphasia • Patients with chronic focal lesions (at least 8 months post stroke) and pervasive language impairments are seen for language treatment • Improvements in behavior are observed as a result of treatment

  24. What is generalization?? TREATMENT Apple Orange

  25. Generalization • Complex to simple generalization • Within category • Across sentence types • Cross linguistic generalization • Trained language-> untrained language • Cross modal generalization • Reading-> naming, writing • Writing-> reading, naming Kiran & Thompson, 2003, JSLHR Kiran, under revision Thompson, Shapiro, Kiran & Sobecks, 2003, JSLHR Kiran, Thompson, & Hashimoto, 2001, Aphasiology Kiran, 2005, Aphasiology Edmonds & Kiran, 2006, JSLHR Edmonds & Kiran, 2004, Aphasiology

  26. Modeling Recovery of language deficits Plaut, 1996

  27. Semantic Space: Typical and Atypical Items • Features for the category birds: • wings • flies • two legs • lays eggs • feathers • builds nest • sings • feathers • beak • nocturnal • eats insects • eats fish • claws • webbed feet • swims Bird Kiran, S & Thompson, (2003), JSHLR

  28. Clothing Typicality in inanimate categories • Features for the category clothing • Worn in warm weather • Has buttons • Has zippers • Decorative accessory • Optional • Protective covering • Worn by women Kiran et al., in preparation

  29. P1: Clothing 100 Treatment BL 90 80 70 60 50 Percent Accuracy 40 30 Atypical-trained 20 Typical-Untrained 10 0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 Probes P1: Furniture 90 BL Treatment 80 70 60 50 Percent Accuracy 40 30 20 Atypical-Untrained 10 Typical-Trained 0 1 3 5 7 9 11 13 15 17 19 21 23 25 Probes Behavioral Data Kiran et al., in preparation

  30. Recovery of language in bilingual individuals

  31. Interpretation of Participant 1 (balanced) results Spanish treatment Semantics “Apio” “Celery” “Cabbage” “Repollo” L1 L2

  32. Participant 2 Participant 3 Spanish (non-dominant language) treatment Semantics Semantics “Tiburón” “Naranja” “Shark” “Ballena” “Orange” “Manzana” “Whale” “Apple” Participant 3 and Participant 2 (both English dominant) Spanish (non-dominant language) treatment

  33. Participant 1 (equally proficient) results Acquisition Treatment Apio N=10 Repollo Generalization (C = 0.705, p = 0.001) N=10 Celery Generalization (C = 0.363, p = 0.071) N=10 Generalization (C = 0.700, p = 0.001) Cabbage N=10

  34. Participant 3 (English dominant) Results Acquisition Tiburón N=10 (C = 0.428, p = 0.082) No Generalization Ballena N=10 Shark N=10 (C = 0.625, p = 0.021) Generalization (C = 0.642, p = 0.018) Generalization Whale N=10

  35. fMRI studies of language recovery in aphasia

  36. Current research questions.. • Are behavioral changes associated with functional changes in the brain? • What are the neural correlates underlying brain plasticity in language recovery • What are typical regions in the brain involved in processing language? • What are regions in the damaged brain that can sub serve residual language abilities • What are regions that can support behavioral language recovery

  37. Patient DG_nonfluent aphasiaPre treatment_picture naming

  38. Patient DG_nonfluent aphasiaPicture naming_post treatment

  39. In normal controls, activation in Broca’s area

  40. Patient 1: Good recovery: activation in perilesional areas or undamaged regions in language dominant hemisphere.

  41. Patient 2: Good recovery: activation in perilesional areas or undamaged regions in language dominant hemisphere. • Right homologous area activation observed in this patient.

  42. Patient 5: Good recovery: activation in perilesional areas or undamaged regions in language dominant hemisphere.

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