Published on August 19, 2009
SPEECH LANGUAGE PATHOLOGY & CLASSIFICATION OF APHASIA
Dr. S. Aswini Kumar. MD
Professor of Medicine
Medical College Hospital
Definitions: Speech is a highly evolved function of the cerebral cortex Speech is the human faculty by which thought processes are symbolically expressed Speech is the vocalization form of human communication It is based upon the syntactic combination of lexicals and names that are drawn from very large vocabularies (usually >10,000 different words) Each spoken word is created out of the phonetic combination of a limited set of vowel and consonant speech sound units
Components of Speech Speech is the mechanical function of one’s ability to communicate in oral language It includes Language production Phonation and Articulation
Language Language is the symbolization of ideas Ist is the ability to convert thought in to comprehensive words It consists of five parameters Speaking Hearing Repeating Reading Writing
Dimensions of Language
Speech and Hemispherical Dominance Speech is the function of cerebral hemisphere It is undertaken by the dominant hemisphere 9 out of 10 human have right handedness 90% of human also have left hemispherical dominance Rest 10% have left handedness 7 out of these 10% have left hemispherical dominance 3 out of the 10% have right hemispherical dominance Thus 97% of human have left hemispherical dominance Only 3% have right hemispherical dominance It also means speech is a function of Left hemisphere in 97 out of 100 and right hemispere in only 3%
Wernickes Area The auditory comprehension of spoken speech takes place in the posterior end of the superior temporal gyrus Karl Wernicke German Neurologist Identified it Described the pathway Connection to Broca’s area Arcuate fasciculus This area is neuroanatomically described as the posterior part of Brodmann area 22
Broca’s Area The motor area for spoken speech which is situated in the posterior part of the left inferior frontal gyrus Peirre Paul Broca French Sugeon Described it in 1865 Two patients who lost speech Autopsy done showed Lesion in lateral frontal lobe This area is neuroanatomically described as the posterior part of Brodmann area 44 and 45
Conduction Area Adeep, white matter tract, connecting the Wernickes area to the Brocas area Also called arcuate fasciculus Latin word Curved bundle Neural tract Important in dominant hemisphere Lesion Conduction Aphasia Repetition deficits arise following damage to the arcuate fasciculus of the dominant hemisphere
Exner’s Area An area of the brain just above Broca's area and anterior to the primary motor control area. Seigmund Exner Austrian Physiologist 1846-1926 Area for writing Close to area for hand movt Damage results in agraphia This area is neuroanatomically described as the posterior part of Brodmann area 6
Reading Area An area of the brain just medial to the left occipital lobe and in the spleniumof the corpus callosum. Center for reading Recieves impulses from eye Transmits to area Assn area Analyses red matter Passes to arcutate fasciculus Lesion – Pure word blindness This area is neuroanatomically described as the posterior part of Brodmann area 17
Speech Mechanism Speech is the process by which a person can communicate with others effectively
Information transmitted via arcuate fasiculus Activation of Brocas area for word formation To motor cortex that control speech muscles
Areas of Brain 4, 6 39 45, 44 41 22 18, 19 17
Speech in reponse to hearing Primary Motor cortex Arcuate fasciculus Brocas Speech area Wernickes Speech Area Primary Auditory Area Brainstem Muscles of Larynx
Pathway in the process of reading Primary Motor cortex Primary Visual cortex Brocas Speech area Wernickes speech Area Visual Association cortex Brainstem Muscles of Larynx
Aphasia Part II
Definitions: Loss of language due to a dysfunction of the central mechanism in the brain is called aphasia Minor disorders of the same is called dysphasia Eg: Right Hemiplegia producing dysphasia Dysfunction of the peripheral mechanism of speech leading to defective articulation is termed dysarthria Eg: LMN facial palsy, Pseudobulbar palsy Loss of voice due to dysfunction of the voice producing mechanism is called dysphonia Eg: Vocal cord palsy , Acute Laryngitis Loss of ability to read: alexia Loss of ability to write: agraphia
Examination of Aphasia Spontaneous speech Whether patient spontaneously ask for food, urination etc Comprehension Whether patient can obey commands Repetition Whether patient can repeat phrases or numbers Naming Whether patient can name an object Reading Whether patient can read, understand and obey Writing Whether patient can write down the answers
Testing Spontaneous speech Fluency Whether speech is fluent without hesitations Uninterrupted by searching for a forgotten word Effort taken for speech See whether the patient has effortless/effortful speech Vocabulary See whether there is any word-finding difficulty Whether patient stammers and stumbles Ability to speak in full sentences Or patient is able to talk only in phrases Grammer Whether the grammer is correct or not
Testing Comprehension Whether patient can hear and understand speech? Tested by asking the patient to obey a command Ask the patient to show the tongue, close eyes, lift a limb Fluency is preserved or not Speech whetherfluent without hesitations? Is it incessant, rapid and uninterrupted? Use of paraphasias Use of a descriptive phrase instead of a forgotten word Use of neologisms Invented word and nonsense words Jargon aphasia Extreme example of the above speech devoid of meanings
Testing Repetition Patient is asked to repeat a simple sentence It has to be clearly stated by the examiner Eg: Today is Wednesday, the August 17th, 2009 See whether the patient is able to repeat what you say Remember never to shout at a aphasic patient Hearing is usually normal in these patients In a patient with left frontal lesion They can repeat simple words and phrases In a patient with posterior lesions in the angular gyrus They cannot repeat what the examiner says This is the characteristic feature of conduction aphasia This function is preserved in Trans-cortical aphasia
Testing for Naming Patient is shown an object and asked to name it A commonly used object should be shown Eg: Pen or match box See whether the patient is able to name the object Patient may be handed over the object Or asked to demonstrate the use of the object In Anomic aphasia or nominal aphasia Patient is unable to name it, but use it even Auditory comprehension, repetition, reading and writing Thse are usually preserved in such a patient Memory testing other wise will be normal This function is preserved in Trans-cortical aphasia
Other test done Ask the patient to read from a command See whether he answers a question written See whether he obeys commands, written down Now ask to read aloud Ask the patient to write down The name and address Draw a picture of a clock face Answer to a question put forward Ask the patient to calculate Subtract 7 from hundred Ask for 4+4, then more complicated
Broca’s Aphasia Non-fluent Telegraphic speech Reduced verbal content Phrase length – generally less then four words Agrammatical sentences (or frequent errors) Mostly content words (nouns and verbs) Absence of functional words ( prepositions & conjunctions) The matter is conveyed any way Functional comprehension is present But trouble following complex grammatical statements Reading loud is not possible; but can read and obey MCA territory stroke – Left frontal lobe
Wernicke’s Aphasia Fluent Increased verbal content Para-grammatism – speech running Phrase length – generally greater than five words Grammatical sentences (or close to normal) Paraphasic errors (literal or verbal) Literal – sound substitution with errors (winging ringing) Symantic – word substitution ( sister for mother) Neologisms (made up words) Logorrhea – Inability to stop speaking Severely impared auditory comprehension MCA territory stroke – Left superior temporal lobe
Conduction Aphasia Relatively uncommon Spontaneous speech is fluent Considerable word finding difficulty Preserved auditory comprehension Significan difficulty with repetition Literal paraphasia Self correction Numerous pauses Filled pauses – Aaaaa Aaaaa Reading deficit - variable Writing deficit – variable Lesion: Left superior temporal area, supramarginal gyrus
Nominal Aphasia Primary deficit – word finding and naming Speech output is fluent with numerous pauses Pauses may be filled with circumlocutions Describing the function of an object But the name cannot be retrieved Auditory comprehension is intact Reading and writing are also intact Last localized of all aphasias Focal damage to left temoral and parietal Usually residual of good recovery from other aphasias Also indicates good prognosis if seen in acute stage
Global Aphasia Severe impairment in all modalities Speaking, listening, reading and writing Severely impaired auditory comprehension Very limited speech output Only few understandable utterances Some areas of spared speech function Utilized in communication Brain damage resulting is massive Fronto-tempero-parietal lesion Complete occlusion of MCA Rarely without hemiplegia
Trans-cortical Motor Aphasia Similarities to motor aphasia But with intact repetition Lesion in the border zone Superior or anterior to Broca’s area Non-fluent Limited speech output Auditory comprehension – good Reading comprehension – good Syntax not as bad as in Broca’s Aphasia Occlusion of Anterior Cerebral Artery
Trans-cortical Sensory Aphasia Similarities to snsory aphasia But with intact repetition Deficits in all language modalities Fluent aphasia Echolalia They can repeat; but cant understand it Much difficulty in communicating Syntax not as bad as in Broca’s Aphasia Lesion in the border zone Posterior and inferior to Wrnickes area Occlusion of Anterior Cerebral Artery
Aphasias - Comparison
Related disorders Part III
Apraxia Acquired disorder of learned skill affecting sequential motor movements which cannot be accounted by elementary disturbances of strength, co-ordination, sensation or comprehension Inability to perform a learned motor activity in the absence of any motor, sensory or coordination defect It is not a lower level motor disturbance but a deficit in the motor planning Ideamotor apraxia is the most common type, fails to perform previously learned motor activity Ideational apraxia is adisturbance of complex motor planning than ideamotor apraxia
Agnosia An acquired disorder of recognition in some sensory modality ie visual, auditory or tactile Agnosia can be specific for a particular class within the modality of sensation – Objects Pictures Faces Colors It is to important distinguish agnosia from agnosia, just as in case of apraxia Patietns with auditory agnosia hear adoor bell ring; but does not recognise it meaning
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