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 3. Language versus involvement of other Cognitive Processes 4. Results from brain damage

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

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

www.stroke.org

Cerebral hemorrhage: tissue necrosis Cerebral infarct Cerebral hemorrhage

Cerebral infarct Cerebral hemorhage Multiple infarct

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

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

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

Comprehension deficit: Can be impaired to variable degrees. 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

Types of aphasia Broca’s Aphasia Production: Naming impaired 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

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

Conduction Aphasia Production Impaired naming Repetition 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

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

Naming

Framework for lexical access Semantic representation Phonological representation Phoneme level Activation of network of features Influenced by frequency, imageability, animacy Sequential: 2 stages (Levelt, 1989) Interactive: Bi-directional links (Dell, 1986) While a broad area of my research is language processing and recovery in aphasia, today I am going to specifically talk about one aspect of language- that is lexical semantic processing and naming. I am going to use this general framework that you see here in making three points 1. The factors in involved in normal lexical semantic processes and naming 2. The effects of brain damage on any of these modules, and I will spend some time on semantic representations 3. The potential effect of theoretically motivated treatment on rebuilding or facilitating improvements in these modules. The framework of lexical semantic processing is barebone view of naming. There are a multitude of models and theories that explain each and every aspect of this process, and my aim is not to go into any of these models/theories in detail, but to provide you with the basic elements of this process, When a picture is presented for naming, the corresponding semantic representation of the picture is activated, and in order to produce to the name of the target- in this case “rose”- the corresponding phonological representation is activated. To produce rose in the right sequence, the phoneme level is activated. Of course, the story is not as simple as this. Within the semantic representation there are numerous factors that influence the process of semantic access, such as frequency, imageability, animacy, number of meanings, category structure, typicality and so forth. The next important aspect of this framework is the connection between semantic and phonological representations. On a continuum of theories, one extreme the sequential models suggests this semantic processing to precede phonological processing. On the other extreme, the interactive activation models, such this connection to interactive and simultaneous, that is semantic activation and phonological activation are almost simultaneous. The next aspect of this framework, is the phonological level as called by the sequential models or the word level labeled by the interactive models. This representation essentially codes the phonological form to produced, and again according to the sequential model is just single address/form selected. According to the interactive models, there would be multiple word nodes activated, and following lateral inhibition, the most active node is selected. The process at the phoneme level is essentially the same, information regarding segmental structure, stress etc, is also coded. Activation of corresponding address or Activation of potential nodes

Interactive activation model

A Neural network model of lexical processing Plaut, 1996

Rapp & Goldrick, 2000

Rehabilitation of aphasia

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

What is generalization?? TREATMENT Apple Orange

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

Modeling Recovery of language deficits Plaut, 1996

Semantic Space: Typical and Atypical Items Features for the category birds: wings flies two legs lays eggs feathers builds nest sings beak nocturnal eats insects eats fish claws webbed feet swims Bird One approach to imagine a semantic category representation is a multidimensional space with the prototype in the center of the semantic boundary.This is same model that Plaut uses as well. Since the typical examples are more similar and share more features with the prototype, they are in the center of the boundary/ So for example, Robins and sparrows share features such as small size, live in trees, have wings, fly and so forth. These are features possessed by the prototype as well Atypical examples on the other hand share less features with the prototype, and are also different from each other, and they are represented in the periphery of the boundary. So for example, penguin has features such lives near water, eats fish, while ostrich have features such as long neck, long legs, which are not shared by each other, but provide variation regarding the features which exist in a category, and still make a penguin or ostrich a bird. Kiran, S & Thompson, (2003), JSHLR

Typicality in inanimate categories Clothing 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

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

Recovery of language in bilingual individuals

Interpretation of Participant 1 (balanced) results Spanish treatment Semantics “Apio” “Celery” “Cabbage” “Repollo” Provision of treatment in Spanish for participant 2 who was equally proficient resulted in improvements in the items trained as well as generalization to the semantically related items in the same language. Crosslinguistic generalization was also observed for English translations like celery and for the semantically related items such as cabbage. These results suggest that, in a balanced bilingual individual, the connections between all components are relatively equal and hence crosslinguistic generalization occurs as a function of treatment. L1 L2

Participant 3 and Participant 2 (both English dominant) Semantics “Orange” “Naranja” “Apple” “Manzana” Spanish (non-dominant language) treatment Participant 2 Semantics “Shark” “Tiburón” “Whale” “Ballena” Participant 3 Spanish (non-dominant language) treatment So to interpret these results: Participant 1 who was English dominant, upon receiving treatment in his dominant language, was improved on access to trained items and to semantically related items in the same language. No crosslinguistic generalization was observed from English-Spanish. Training this patient on his non-dominant language, however, resulted in improved access to the items trained, although no improvements were observed to semantically related items in the same language. Improvements were observed in English language. That is training naranja improved access to orange and well as further improvements to apple.

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 Participant 2, who was also unable to name any items in baseline, was treated on spanish set 1, which included items like apio. Performance on those items improved to criteion as did the semantically related items in the same language. Crosslinguistic generalization was also observed for the translations in English, so apio improved its English translation “celery” and generalization was observed the semantically related item in English also, that is repollo improved cabbage. Only if there are questions The two items that the subject got correct (2/5) in the Spanish control items were sobre (envelope) and bombero (fireman). Initially, she called sobre “carta” (letter), which is semantically related. She was soon able to make the connection. For “bombero,” she could already access the word in English during baseline, AND her ex-husband was a fireman, so she worked very hard to “translate” fireman to bombero during probes. The English unrelated were “less correct” to start with and so have not improved. Generalization (C = 0.700, p = 0.001) Cabbage N=10

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

fMRI studies of language recovery in aphasia

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

Patient DG_nonfluent aphasia Pre treatment_picture naming

Patient DG_nonfluent aphasia Picture naming_post treatment

In normal controls, activation in Broca’s area

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

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

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