Week 3 Jan 27, 2011

 Word finding difficulty is one of the striking feature of aphasia (T/F)  Aphasia is a language impairment affecting all four modalities of language (T/F)  Writing is typically least impaired area in an individual with aphasia (T/F)  Aphasic individuals are good at using ________ forms of speech  Aphasia is an impairment of intellectual functioning such as reasoning, problem solving, etc. (T/F)

 Understand the explanations for Aphasia  Learn about the etiology of Aphasia  Understand the Aphasia classification systems  Discuss the symptomatology of different forms of fluent Aphasias  Wernicke’s Aphasia  Conduction Aphasia  Anomic Aphasia  Transcortical sensory aphasia

 Two orientations: Neurological and cognitive  1. Neural processes (i.e., neurons, cerebral areas)  2. Psychological or mental processes (i.e., ideas or memories, comprehension) Relationship between ideas and words

 Features and severity of neurogenic communication disorders depend on location and magnitude of the damage… (Brookshire, 1997)

Luria (1970) – three functional divisions 1. Brainstem: general awareness and distribution of sensory input 2. Posterior cortex: perceives, recognizes, and integrates sensory information 3. Anterior cortex: generates volitional response

 Focal lesions (e.g., stroke)  multifocal lesions (e.g., little strokes through the year)  diffuse lesions (spread evenly throughout the brain)

 Left and Right hemispheres have different functional specialties (i.e., Left- language and Right – nonverbal)  Within the left: anterior – nonfluent, posterior – fluent form of aphasia

 Encoding and decoding messages – relationship between ideas and words stored in our memory  Two features of cognition  Knowledge (stable storage) – about the world and language we speak  Process – transient activity of mind, a response to stimulus  Memory is the key to carryout all cognitive functions

 Long-term memory (LTM)  Different types of knowledge  Episodic memory  Semantic memory- common knowledge  Procedural memory  Lexical memory- words and knowledge about words

 Working memory (WM) – work space of any cognitive activity  Short-term memory is one component of WM

 Cognitive processing including language processing  Constrained by the capacity of WM  Draws knowledge from LT storage  Operates at automatic and controlled levels  In aphasia  language storage system is relatively intact  Impairment of processing

 Aphasia is a selective impairment of the cognitive system specialized for comprehending and formulating language, leaving other cognitive capacities relatively intact. (Davis, 2007, p.15)

 Deprivation of Blood Supply  Cerebrovascular Accident or CVA  1) Thrombosis ▪ Buildup of fatty tissues and other deposits on wall of artery ▪ Over time, artery hole is totally blocked, leading to thrombosis  2) Embolism: substance originating from another part of body, usually heart, lodging itself in brain blocking blood flow – CVA is instantaneous

 Spilling of Blood – blood spills on neurons causing damage to them  Hemorrhage  1. bursting of aneurysm: walls of artery become weak causing swelling or bulging of artery wall (pressure of blood causes bursting)  2. trauma: rupturing of blood arteries causing hemorrhage Subarachnoid hemorrhage (SAH) is bleeding into the cerebrospinal fluid (CSF) of the subarachnoid space surrounding the brain.

 A. Receptive versus expressive aphasia ▪ 1. based on predominance of one set of abilities over another ▪ 2. major difficulties related to language reception or expression

 B. Anterior versus posterior aphasia : anatomically-based  C. Fluent versus nonfluent aphasia ▪ 1. divides patients based on verbal output ▪ 2. using this dichotomy, patients can be additionally classified

 Fluent  a. patients who produce longer phrases  b. five or more connected words  c. speak more than 75 words per minute  Nonfluent  a. those who produce only single word utterances or short phrases  b. four or fewer connected words  c. speak 50 or fewer words per minute

Posterior lesions Discharged early – may not be referred to speech- pathologist They are not controllable (stimulus-response model) – agitated, suspicious They are fewer than fluent aphasics Mixed up with confused patients (misdiagnosed) Older than most aphasic patients (mean age -63 Vs 52 in Broca’s)

Three syndromes based on speech features: Wernicke’s, conduction, anomic (dysproportionality features, it is not all or nothing) – Long- standing classification ▪ Melodic line – intonational pattern encompasses entire sentence ▪ Phrase length- length of uninterrupted word groups ▪ Articulatory agility – ease with which patient articulates phonemic sequence ▪ Grammatical forms – variety of grammatical construction

Set of behaviors associated with a generally similar lesion. Wernicke postulated that traces of words would be stored at or near the Sylvian fissure (first temporal gyrus) Defective auditory comprehension

Poor self-monitoring Fluent but paraphasic speech (due to loss of the internal correction of the motor process) Paraphasic speech pattern is unnoticed by the speaker (due to impaired auditory monitoring) Defective repetition skills (due to impaired auditory comprehension)

Both reading and writing usually disrupted including reading comprehension Verbal expression consists of a) word finding problems b) verbal paraphasias (semantic and unrelated) c) some phonemic paraphasias d) neologisms e) jargon g) paragrammatism ▪ Press for speech: irrepressible intention of the speaker to continue in his monologue (possible due to lack of correction over output) ▪ increase in awareness of errors usually demonstrates an improvement in comprehension

▪ Because posterior lesion, usually show no paralysis (hemiplegia) or weakness (hemiparesis) in extremities ▪ LD5jzXpLE&feature=related LD5jzXpLE&feature=related ▪ Lesion site: ▪ Posterior portion of STG ▪ The auditory association area or Wernicke’s area ▪ Kertesz et al. (1993) found that persisting Wernicke’s aphasia usually involves the supramarginal and angular gyri in addition to the superior temporal area

Functional reorganization of language after stroke Recovery of function in Wernicke’s aphasia may be accompanied by a redistribution of activity within both cerebral hemispheres. fMRI data suggests that clinical recovery is associated with a redistribution of function to the right hemisphere (Thurlborn et al., 1999; Cherney & Robey, 2001)

 Comprehension deficit  Fluent but paraphasic speech  Reading comprehension deficits: Aphasic Alexia  Oral reading versus reading comprehension  Writing deficits

 Ancillary behaviors:  Depression: 37% (cumulative) ▪ Major post stroke depression ▪ Reactive post stroke depression ▪ Sadness, dependency and indecisiveness Lesion causing Wernicke’s symptomatology may go unnoticed.

 1. Locus of lesion is parietal operculum or arcuate fasciculus although controversy exists over lesion site Left hemisphere supramarginal gyrus and arcuate fasciculus The insula, and underlying white matter of left hemisphere Small lesions of Wernicke’s area More anterior and inferior lesions (anterior supramarginal gyrus, underlying white matter, angular gyrus, and insular cortex) are deemed responsible for phonologic output problems

▪ 2. breakdown in transmission of information from posterior to anterior regions ▪ 3. relatively good auditory comprehension ▪ 4. verbal expression consists of ▪ Fluent, preserved melody, variety and complexity of syntactic structures ▪ word finding problems, ▪ paraphasias with much higher incidence of phonemic than verbal paraphasias; ▪ hallmark feature of disorder is severe repetition deficit, especially for functions and numbers ▪ 5. much more aware of errors and more interested in correcting errors than Wernicke’s patients probably due to better comprehension ▪ 6. visual comprehension is relatively intact and writing skills mirror verbal output

 Disconnection Model  Conduction aphasia as disconnection between the auditory “comprehension” region and the speech “production” region.  Repetition, which requires interaction between two centers is imapired  Many have challenged the rigid disconnection model of conduction aphasia

The Bimodal distribution model: damage along the continuum extending from Wernicke’s area to Broca’s area. Researchers have reported variability in the degree of fluency with the less fluent patients exhibiting more anterior lesions; those with higher fluency scores had more posterior lesions (Kertesz et al., 1977)

 The “Two” Conduction Aphasias  Two disorders with distinct pathophysiologic mechanism (Nadeau, 2001) ▪ Repetition conduction aphasia ▪ Repetition conduction aphasia: deficit in auditory short-term memory, disturbance only of verbal repetition tasks ▪ Reproduction conduction aphasia ▪ Reproduction conduction aphasia: more general language impairment affecting phonologic output process ▪ Deficits in word production across verbal tasks including conversation, naming, and oral reading as well as repetition. ▪ These two types of difficulties arise from lesions in functionally distinct but anatomically adjacent areas in temporoparietal region

 Primary criteria for diagnosis  Fluent, paraphasic conversational speech  No significant difficulty in comprehension of normal conversation  Significant verbal repetition disturbance  A preponderance of phonemic paraphasias

 Differentiating features (text book, pg 156) Broca’s Aphasia/ AOSConduction Aphasia NonfluentFluent ( WPM) DysprosodyIntact prosody AgrammaticPreserved grammer or paragrammatic Comprehension relatively good Repetition impaired proportionate to other verbal tasks Repetition disproportionally impaired Error recognition Probably anomic

 More description of salient features: Fluency ▪ Fluent but not as fluent as Wernicke’s aphasics Word finding (content words): Some variability Paraphasias: phonemic paraphasias ▪ produce more errors on a forced choice of specific target words Error recognition Repetition ▪ Difficulties appear more on phrases, short sentences, poly syllabic words Auditory comprehension Reading

 Favorable spontaneous recovery pattern  Conduction aphasics show significant or even complete recovery  Sometimes they “evolve” from classifications such as “jargon or Wernicke’s aphasia  They perform well in situations that do not require single- word accuracy or specific responses.

▪ Poorly localized: angular gyrus lesion and/or posterior middle gyrus ▪ Many Wernicke’s evolve into Anomic ▪ 1. Empty speech: lot of words like, thing, it, you know what I mean.. Frustrated ▪ 2. relatively good auditory comprehension

▪ 3. verbal expression consists of predominance of word finding problems with the more salient the word, the more difficulty finding it and an absence of paraphasic errors (emptiness of substantive words in speech) ▪ 4. reading and writing skills vary from patient to patient due to how extensive the lesion posteriorly – the more posterior the lesion, the more involved are reading and graphic impairments

▪ 1. like severe Wernicke’s aphasia in verbal output with verbal paraphasias (both unrelated and semantic), phonemic paraphasias, neologisms, word retrieval deficits – more jargon ▪ 2. very poor auditory comprehension

▪ 3. unlike Wernicke’s aphasia, repetition is intact as well as a preservation of memorized material ▪ 4. lesion is in posterior part of parietal lobe with sparing of Wernicke’s area and arcuate fasciculus fibers (referred to as watershed lesion) ▪ 5. written language is impaired for both reading and writing

Wernicke’s Conduction Transcortical sensory Wernicke’s Conduction Transcortical sensory Auditory comprehension Severely impaired Slightly impaired Severely impaired Reception Impaired Impaired Intact Speech Fluent, paraphasic Paraphasic Fluent, Paraphasic Reading Impaired Intact Impaired Writing Impaired Impaired Impaired Behavioral Patterns of Types of Aphasia