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APHASIADr V B Kasyapa J
GM I yearDate: 20/09/16
Definitions
• Phonation: Production of vocal sounds without word formation.– Function of Larynx
• Vocalisation: Sound made by the vibration of the vocal cords and modified by vocal tract.– Symbolise & communicates ideas and thoughts– Function of Vocal tract
Definitions
• Articulation: Enunciation of words and phrases.– Function of organs & musculature innervated by
brainstem.• Language: Mechanism for expressing thoughts &
ideas– By speech (auditory symbols)– By writing (motor symbols)
(or)Any means of expressing or communicating a feeling or thought using a system of symbols.- Function of Cerebral cortex.
Definitions
• Grammar/ Syntax: Set of rules for organizing the symbols to enhance their meaning.
• Symbols of language: – Sounds– Marks– Gestures, etc…
• Semantics : the study of meaning in language• Prosody : the patterns of stress and intonation in
a language
Linguistic communicationMotor acts necessary for execution
Reception
Interpretation of auditory & visual images
Retention
Recall Visualisation of symbols
Association of motor centres that control expression
Motor elements of expression
Slurred speech/ Difficulty in speechDysarthria Aphasia
Disorder of motor production (or) articulation
Disorder of language
Normal Language Language is abnormal
Unable to coordinate muscles of speech Unable to comprehend or express the speech
Associated with other bulbar abnormalities (dysphagia/ brain stem lesions)
Associated with other language functions like reading, writing,…
May not be a brain disease Always due to a brain disease
APHASIA - Definition
• A disorder of language, including various combinations of impairment in the ability to spontaneously produce, understand and repeat speech, as well as defects in the ability to read and write.
or• Disorders of previously intact language abilities
due to brain damage; not due to paralysis or disability of the organs of speech or of muscles governing other forms of expressions.
HistoryScientist Contribution
Dax (1836) Relationship between aphasia and lesions of left hemisphere
Broca (1861) Loss of speech with lesions of left inferior frontal convolution
Trousseu (1862) First used term ‘Aphasia’
Wernicke (1874) Loss of speech comprehension (word deafness) from lesion of left superior temporal gyrus (LSTG)
Lesion posterior to LSTG (region of Angular gyrus) is associated with word blindness (inability to comprehend written words)
Conduction aphasia description
Lichtheim (1885) Subcortical aphasia
Wernicke-Lichtheim model of cortical speech areas
Bason, Geschwind Wernicke-Geschwind model of cortical speech areas
H Jackson Affected language function may not necessarily related to the location of lesion
Cortical level of language comprehension
• Level of arrival : perceived language symbols, seen/ heard.– No further differentiation of impulses– Primary cortical reception areas
• Level of Knowing : Recognition of impulses– Formulation of engrams for recall of stimuli revisualisation
• Level of Expression : Recognition of symbols in forms of words.– Higher elaboration and association of learned symbols as
language
Levels of Motor speech function
• Emotional Level : Most primitive– Response to painful stimuli
• Automatic level : automatic speech– Yes or no; counting days
• Proportional level : vocalisation on volition, symbolic or intellectual language– Communication of thoughts, ideas, feelings and
judgement using words, syntax, semantics and rules of conversation.
ANATOMY OF SPEECH AREAS
• Language functions are not discretely localised in brain as vision/ elemental senses.
• But more localised than intelligence/ judgement/ creativity
• Primary cortex effected – focal deficits• Association cortex effected – higher cortical
malfunction
• Mainly located in peri-sylvian areas of language dominant hemisphere
Pre Rolandic/ Anterior areas Post Rolandic/ Posterior areas
Para sylvian inferior frontal(PIF) areas Para sylvian superior temporal(PST) areas
Motor/ expressive aspects Sensory/ perceptive aspects
By Superior division of MCA By Inferior division of MCA
Area Location function
Broca’s Inferior frontal gyrus Motor association area
Just anterior to primary motor areas for the lips, tongue and face
Executive area for language function
Left precentral gyrus of Insula
Cortical area beneath frontal and temporal lobes
Motor planning of speech
Wernicke’s Superior temporal gyrus Sensory association cortex
Posterior to primary auditory cortex
Arcuate faciculus
Deep white matter tract Connection between association areas
From Wernicke’s area -> around posterior end of sylvian fissure -> sub cortical white matter of insula -> to Broca’s
? Relay station in pre motor/ motor area
Additional fibres from subcortical white matter of insula
Area Location Function
Angular gyrus
Inferior parietal lobule Reading and similar non verbal language function
Caps posterior ramus of sylvian fissure
Between Wernicke’s and visual cortex
Supra marginal gyrus
Between visual cortex and posterior peri sylvian language areas
Visual language function
Exner’s writing centre
In middle frontal gyrus of language dominant frontal lobe
Writing
Near frontal eye field ? Connections with Wernicke’s through white matter tracts
Anterior to primary motor cortex of hand
Classification of Aphasia
• Difficult to classify.• Frequently mixed• Lesions similar in size & location on imaging
studies may be associated with different aphasic syndromes even in persons with identical cerebral dominance for speech.
• Pure forms are uncommon• Sometimes, there may be no peri-sylvian lesion.
• Crude classification :– Expressive aphasia vs. Receptive Aphasia (Speech defect vs. Understanding defect)– Non fluent vs. Fluent– Motor vs. Sensory– Anterior vs. Posterior– Central vs. Para-central(Involves peri-sylvian vs. Watershed area infarction)(Loss of repetition vs. Normal repetition)
BROCA’s APHASIA
• Lesion : Anterior peri-sylvian speech areas in PIF region.
• Speech : Laboured– Non fluent spontaneous speech– Decrease amount of linguistic output• Few words• Short sentences• Poor grammar
– Telegraphic (without linking words)
– Para/ Agrammatism (misuse of words & defective syntax)
– May preserve emotional & automatic speech (may even possible to sing)
– Unable to repeat what they heard/ unable to read aloud
– Monophasia (recurrent utterances)• Able to comprehend (may seem inability with
difficult material; grammar > semantics)
BROCA’s APHASIA
• Self aware and frustrated.• If writing involves -> non paretic left hand may
also involves
• If writing spared -> Verbal apraxia
• Milder form: occasional errors in word formation, word finding difficulty on rapid fire manner
BROCA’s APHASIA
• Associated with
– Contralateral hemiparesis/ facio-brachial paresis
vision is spared
– Buccofacial apraxia -> Dysarthria
– Alexia (third alexia of dejerine) - inability to
recognize or read written words or letters
BROCA’s APHASIA
Apraxia of speech/ mini-Broca/ baby-Broca/ Cortical dysarthria
• Lesion : only Broca’s area involved• Speech : Forgets how to make sounds of speech– Only speech is effected– Prosody is impaired -> shuttering quality (like foreign
language)– Normal grammar with correct language– Syllable transposition (“pasghetti”)
• Defective control without weakening vocal tract• Normal comprehension• Normal writing
Pure word mutism/ Aphemia/ Pure motor aphasia of Dejerine
• Inability to speak
• Normal auditory comprehension
• Normal reading and writing
• Lesion : small lesion in PIF area
Wernicke’s Aphasia
• Lesion : PST region (Auditory association cortex, Angular gyri & Supramarginal gyri)
• Speech : Fluent, Effortless– Normal prosody, sentence length & phrase– Word deafness (unable to understand speech)– Word blindness (unable to read)– Normal/ Increased word output (logorrhoea/
hyperlalia)– Naming & Repetition defects (from poor
comprehension)
Wernicke’s Aphasia– Paraphasic errors– Neologism (new words)– Agrammatism– No meaning with gibberish utterances– May also evolve from a state of mutism
• Not able to understand what he is speaking -> agitated -> gibberish talk (like psychotics)
• Dissociation between comprehension deficits for spoken and written languages may be seen
Wernicke’s Aphasia
• Mini-Wernicke’s : mild paraphasia– Minimal difficulty in understanding grammatically
complex material• Jagron aphasia/ Word salad : Plentiful words
wrongly used• Association with larger areas of involvement– Visual disturbances– No hemiparesis
Global Aphasia
• Lesion : large sized in entire peri-sylvian language centre
Or separate lesions involving PIF & PST
• Mostly due to occlusion of ICA or proximal MCA.
Global Aphasia
• Speech : grossly non fluent
– Severe comprehension deficit
– Anomia, no repetition
– Severe Monophasia
• Associated with Hemiplegia and field defects
Conduction Aphasia (Leitunsaphasie)
• Lesion : interruption the conduction between Wernicke’s and Broca’s area– Deep white matter lesion in supramarginal gyrus– Involves Arcuate Fasiculus (AF).– Embolic occlusion of a terminal branch of MCA
may cause this aphasia in cortical injury• Disconnection syndrome : dissociation
between anterior and posterior peri-sylvian language areas
Conduction Aphasia (Leitunsaphasie)
• Speech : poor repetition– Relative preservation of other language functions– Impaired comprehension (unlike WA)– Paraphasia– Relatively fluent– Variable Naming difficulty– Difficult to read aloud– Difficulty in writing dictation
• Patient is aware and tries to correct.
Anomic Aphasia• Definition :– Should be called only if the naming is isolated
deficit throughout the course of illness.– Any aphasia type as it develops/ recovers may
pass through a stage like this
• Also called “Non localising syndrome”• Only disease which suggests a lower temporal
lobe lesion
Anomic Aphasia• Speech : Naming deficit
– Fluent– Normal comprehension– Able to repeat– Empty speech (due to word-finding deficits)– Paraphasias– Circumlocution
• Dysnomia : mild difficulty in naming
• May associated with wide variety of diseases– If association with Gerstmann’s syndrome, lesion may be in the
dominant Angular Gyrus.
Trans Cortical Aphasia (TCA)
• Lesion : a disconnection of peri-sylvian area from rest of the brain– But PST & PIF with AF are intact
• It can be divided as– Mixed TCA– Trans Cortical Motor Aphasia (anterior isolation
syndrome)– Trans Cortical Sensory Aphasia (posterior isolation
syndrome)
Trans Cortical Aphasia (TCA)
Mixed TCA (MC)
• Lesion : at BZI, both PST & PIF separated from rest of the brain
• Repetition – excellent (up to Echolalia)
• Non fluent• No comprehension
TC Motor A
• Lesion : more anterior, separation of PIF is more
• Like Broca’s• Repetition – good• Non fluent• Intact
comprehension
TC Sensory A
• Lesion : more posterior, PST isolation from word association areas in parieto, temparo occipital cortex
• Like Wernicke’s• Repetition – good• Fluent• No comprehension• Associated with
hemiparesis or other CNS symptoms
Sub Cortical Aphasia
• Lesion : no damage to peri-sylvian cortical area in direct.– Imitates TCA– May involve• Thalamus‘• Caudate nucleus• Putamen• Peri ventricular white matter• Internal capsule of language dominant hemisphere
Sub Cortical Aphasia
Anterior syndrome : lesion at caudate/
straito capsular area
• Non fluent• Dysarthric• Good comprehension• Poor naming• Repetition preserved• Broca’s like but Non
telegraphic
Posterior syndrome : lesion at thalamus
• Fluent• Non dysarthric• Poor comprehension• Poor naming• Repetition preserved• Wernicke’s like but
with hemiplegia
Sub Cortical Aphasia
Proposed Mechanisms
May involve secondary dysfunction of peri-sylvian
language areas due to interruption of fibres
communicating between cortical and subcortical structures
Cortical hypo perfusion due to subcortical infarct.
Non fluent
Good comprehension
Good repetition
Transcortical Motor Aphasia
Bad repetition
Aphasic writing
Broca’s Aphasia
Normal writing
Verbal Apraxia
Bad Comprehension
Good repetition
Mixed trans cortical Aphasia
Bad repetition
Global Aphasia
APHASIA GUIDE
Fluent
Good comprehension
Good repetition
Anomic Aphasia
Bad repetition
Conduction Aphasia
Bad comprehension
Good repetition
Trans cortical sensory aphasia
Bad repetition
Poor reading
Wernicke’s Aphasia
Normal reading
Pure word deafness
APHASIA GUIDE
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