APHASIA and APHASIC SYNDROMES PRESENTATION NEUROLOGY

Aphasia

1. APHASIA

2. Definitions Historically, language was the first higher cortical function to be correlated with specific sites of brain damage. Aphasia is defined as a disorder of language that is acquired secondary to brain damage. (Alexander and Benson, 1997). Differentials: Dysphasias : Congenital or developmental language disorders. Disorders of speech : Dysarthria , dysphonia , stuttering, speech apraxia . Disorders of thought : Psychiatric disorders derange thought and alter the content of speech without affecting its linguistic structure.

3. Definitions Phonemes are the smallest meaning-carrying sounds. Morphology is the use of appropriate word endings and connector words for tenses, possessives, and singular versus plural. Semantics refers to word meanings. Lexicon is the internal dictionary . Syntax is the grammatical construction of phrases and sentences. Discourse refers to the use of these elements to create organized and logical expression of thoughts. Pragmatics refers to the proper use of speech and language in a conversational setting, including pausing while others are speaking, taking turns properly, and responding to questions.

4. Introduction Paraphasias Phonemic / literal Semantic / verbal Logorrhea : Excessively fluent Palilalia , echolalia and Perseveration Neologisms : Non existence words Jargon speech : Paraphasias + Neologisms = Meaning cannot be discerned

5. Areas and their connections

6. Anatomy

7. Anatomy Cerebral dominance and its relation to language Crossed aphasia Emotional language and prosody

8. Anatomy Subcortical areas in language Thalamus Basal ganglia (Caudate and putamen )

9. Classification of Aphasia

10. APHASIC SYNDROMES

11. Lesion: Posterior part of the inferior frontal gyrus , along with damage to adjacent cortex and subcortical white matter. Superior division of MCA Clinically Paucity of words Aggramatism Comprehension of complex syntax may be altered Tip of tongue Frequently associated with depression. Broca Aphasia (Paul Broca )

12. Broca Aphasia (Paul Broca ) Orobuccal apraxia Sympathetic apraxia ‘‘Mini’’ or ‘‘baby’’ Broca (Verbal apraxia)

13. A rare variant of Broca aphasia. A nonfluent syndrome in which the patient is initially mute and then able to speak with phoneme substitutions and pauses. All other language functions are intact, including writing. Usually transitory syndrome Small lesions of the Broca area or its subcortical white matter or of the inferior precentral gyrus . Because written expression and auditory comprehension are normal, aphemia is not a true language disorder; aphemia may be equivalent to pure apraxia of speech. Pure Word Mutism ( Aphemia )

14. Lesion: Posterior Superior Temporal. Inferior division of Middle Cerebral Artery, sometime supto inferior parietal lobule. Clinically Logorrhea Paragrammatism Pharaphasia Circumlocution Jargon aphasia Partial or complete right homonymous hemianopia. Depression is less common; many Unaware of or unconcerned about their communicative deficits. With time, some patients become angry or paranoid about the inability of family members to understand them. Wernicke Aphasia (Carl Wernicke )

15. CLASSIFICATION Wernicke Aphasia (Carl Wernicke )

16. Pure word deafness Rare syndrome of isolated loss of auditory comprehension and repetition, without any abnormality of speech, naming, reading, or writing. Most cases have mild aphasic deficits, especially paraphasic speech. Classically, the anatomical substrate is a bilateral lesion , isolating Wernicke’s area from input from the primary auditory cortex, in the bilateral Heschl’s gyri . An example of a “disconnection syndrome,” in which the deficit results from loss of white matter connections rather than of gray matter language centers. Partial Wernicke’s patients may also manifest with PWD. Lesion: Bilateral lesions in middle third of superior temporal gyri Vessel: Embolic occlusion of a small branch of inferior division of MCA

17. Pure Word Blindness Alexia Without Agraphia / Visual Verbal Agnosia Reading Letter by letter reading and Asyllabia Lesion: Medial occipital lobe, splenium of corpus callosum and medial temporal lobe Vessel: Left PCA territory

18. Global Aphasia Summation of the deficits of Broca aphasia and Wernicke aphasia. Milder aphasic syndromes in which all modalities of language are affected are often called mixed aphasias. Usually large lesions, involving both the inferior frontal and superior temporal regions, and often much of the parietal lobe in between. (represents most of the territory of the left MCA.) Patients in whom the superior temporal gyrus is spared tend to recover their auditory comprehension and to evolve towards Broca aphasia.

19. Global Aphasia Associated right hemiplegia , hemianesthesia and homonymous hemianopia Recovery Lesion: Large vs two separate lesions Vessel: Proximal MCA

20. Transcortical And Conduction Aphasias Interruption of association pathways joining the primary receptive areas to the language areas Pure word deafness, Pure word blindness & Pure word mutism Interruption of sensory area from motor area Conduction aphasia Interruption of perisylvian language areas from other parts of cerebral cortex Transcortical aphasia

21. Conduction Aphasia Striking inability to repeat. Reading aloud may be impaired. Usually involve either the superior temporal or inferior parietal regions. May represent a stage of recovery in patients with Wernicke aphasia in whom the damage to the superior temporal gyrus is not complete. Conduction aphasia has been advanced as a classical disconnection syndrome : Arcuate fasciculus.

22. Conduction Aphasia Efferent reproduction type : Abnormal phonemic organization and representation of words Parietal and insular damage Afferent repetition type : Abnormal repetition of large strings of material Temporal lobe damage The supramarginal gyrus appears to be involved in auditory immediate memory and in phoneme perception related to word meaning, as well as phoneme generation. Lesions in this area are associated with conduction aphasia and phonemic paraphasic errors. Alternative hypothesis: A defect in auditory verbal memory (Immediate recall) Lesion: Superior temporal (without limb apraxia) or inferior Parietal region (with limb apraxia) Vessel: Embolic occlusion of ascending parietal or posterior Temporal branch of MCA

23. Anomic Aphasia Access to lexicon is impaired. Non-specific localization. Most common. Probable locus: Angular gyrus , Superior temporal lobe. Inability to produce nouns is characteristic of temporal lobe lesions, whereas inability to produce verbs occurs more with frontal lesions Encephalopathies , dementia ( Alzheimers ) and as recovery phase of Broca’s aphasia.

24. Transcortical Aphasia Repetition is preserved. Connection between Broca’s and Wernicke’s area is intact, while other areas of brain are unable to connect to the language network. Mixed transcortical aphasia: Isolation aphasia- Echolalia. (Both watershed areas) Transcortical motor aphasia (Anterior isolation syndrome) Transcortical sensory aphasia (Posterior isolation syndrome) Transcortical mixed aphasia Lesion: infract in vascular border zones and advance dementia

25. Anomic Aphasia Most common but least specific type of aphasia Lesion: left posterior lower temporal lobe or frontal lobe Foreign Accent Syndrome Transient phenomenon during recovery from left sided stroke

26. Subcortical Aphasias Diagnosis based on neuroimaging Difficult to classify aphasia syndrome in the presence of dysarthria and right hemiparesis Thalamic aphasia : Fluent aphasia Quasi aphasic abnormality of vigilance Subcartical white matter and basal ganglian aphasia Putamnen , Caude nucleus and anyerior limb of internal capsule. Dysarthria, decresed fleuency , mildly impaired repeteion and mild comprehension inpaired

27. Pure Alexia without Agraphia Linguistic blindness. Left posterior cerebral artery, with infarction of the medial occipital lobe, often the splenium of the corpus callosum , and often the medial temporal lobe. Dejerine postulated a disconnection between the intact right visual cortex and left hemisphere language centers, particularly the angular gyrus . Alternative theory: Deficit in short-term memory for visual language elements, or an inability to perceive multiple letters at once ( simultanagnosia ).

28. Pure Alexia without Agraphia

29. Alexia with Agraphia Acquired illiteracy Previously educated patient is rendered unable to read or write. Anatomy: Inferior parietal lobule, especially the angular gyrus . (Territory of the angular branch of the left middle cerebral artery).

30. Alexias Letter by- letter dyslexia is equivalent to pure alexia without agraphia . Deep dyslexia is a severe reading disorder in which patients recognize and read aloud only familiar words, especially concrete, image able nouns and verbs. They make semantic or visual errors in reading and fail completely in reading nonsense syllables or nonwords . Phonological dyslexia is similar to deep dyslexia, with poor reading of nonwords , but single nouns and verbs are read in a nearly normal fashion, and semantic errors are rare. Patients appear to read words without understanding. Surface dyslexia , involves spared ability to read laboriously by grapheme-phoneme conversion but inability to recognize words at a glance. These patients can read nonsense syllables but not words of irregular spelling, such as colonel or yacht.

31. Neurolinguistic model of the reading process

32. Alexia Alexia without agraphia (Pure word blindness / Letter by letter reading) Alexia with agraphia ( Acquired illiteracy) Aphasic alexia (third alexia) Surface dyslexia Deep dyslexia Phonological dyslexia

33. Agraphia Aphasic Constructional Apraxic Linguistic Surface Deep Phonological

34. Language in Rt hemisphere lesions Aprosodia : Flat and unemotional speech Motor aprosodia : Loss of expresive emotion with preservation of emotional comprehension. Sensory aprosodia (Affective agnosia) : Loss of comprehension of affecteive language. He understand what is said, but not how it is said Sensory amusia

35. Landau Kleffner syndrome FOXP2 dependent language functions

36. Bedside Language Assessment SPONTANEOUS SPEECH Informal interview Structured task Automatic sequences NAMING AUDITORY COMPREHENSION REPETITION READING Reading aloud Reading comprehension WRITING Spontaneous sentences Writing to dictation Copying D. Benson and Norman Geschwind , updated by Alexander and Benson, 1997

37. Auditory Verbal Comprehension

38. TESTING Western aphasia battery ( WAB ) Minnesota test for differential diagnosis of aphasia ( MTDDA ) Boston diagnostic aphasia examination ( BDAE ) Porch communicative abilities test Token test

39. Western aphasia battery Aphasia quotient and cortical quotient Aphasia quotient derived from the verbal and auditory comprehension portions: Spontaneous speech Comprehension Repetition Naming These added to scores for reading, writing, praxis and construction, give Cortical quotient Maximum score for both is 100, language is normal if AQ of > 93.8 is achieved

40. Western aphasia battery

41. Minnesota test for differential diagnosis of aphasia Most comprehensive 46 tests divided into 5 sections Auditory disturbances Visual and reading disturbances Speech and language disturbances Visuomotor and writing disturbances Disturbances of numerical relations and arithmetic process

42. MDDA Classifies aphasia into: Simple aphasia- Reduced language function in all modalities with out complicating conditions Aphasia with visual involvement- Simple aphasia with more severely reduced reading and writing functions Aphasia with sensorimotor involvement- Broca aphasia with speech apraxia Aphasia with scattered findings- Generalized brain damage with impaired mental status Irreversible aphasic syndrome- Global aphasia Minnesota test for differential diagnosis of aphasia

43. Types of Aphasia

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45. MDDA

46. Boston diagnostic aphasia examination

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