Speech disorders

Disorders of Speech

Dr. Mayank [email protected]

Introduction• Vocalization is production of sound without linguistic

content.

• Speech is an audible form of communication built on the sounds humans produce.

• Language is a system for representing and communicating information. It can be expressed in a variety of ways including gestures, writing, and speech.

Human Sound and

Speech ProductionHuman speech involves a remarkable coordination of over 100 muscles ranging from those controlling the lungs to those of the larynx and the mouth

The Source filter model of speech production by Johannes Mueller

Disorders of speech and language may be broadly characterized under four headings

1. Aphasia or dysphasia2. Dysarthria and anarthria3. Aphonia or dysphonia4. Disturbances of speech and language with diseases

that globally affect higher-order mental functionAnother separate category is of developmental disorders of speech and language.

Language Is Localized and Lateralized in the Brain

THE DISCOVERY OF SPECIALIZED LANGUAGE AREAS IN THE BRAIN• In 1864 Broca concluded that “on parle avec l'hemisphere gauche"

(''We speak with our left brain).

• The region of the left frontal lobe that Broca identified as critical for articulate speech has come to be called Broca’s area

• In 1874, German neurologist Karl Wernicke reported that lesions in the left hemisphere, in a region distinct from Broca’s area, also disrupt normal speech

• Located on the superior surface of the temporal lobe, this region is now commonly called Wernicke’s area

lies behind the primary auditorycortex in the posterior part of the superior gyrus of the temporal lobe.

located partly in the posterior lateral prefrontal cortexand partly in the premotor area

David Ford’s discussion with psychologist Howard Gardner

“I asked Mr. Ford about his work before he entered the hospital. I’m a sig. . . no. . . man. . . uh, well,. . . again.” These words were emitted slowly, and with great effort. The sounds were not clearly articulated; each syllable was uttered harshly, explosively, in a throaty voice. With practice, it was possible to understand him, but at first I encountered considerable difficulty in this.

“Let me help you,” I interjected. “You were a signal. . . .” “A signal man. . . right,” Ford completed my phrase triumphantly.

“Were you in the Coast Guard?”“No, er, yes, yes. . . ship. . . Massachu. . . chusetts. . . Coastguard. . .years.” He raised his hands twice, indicating the number “nineteen.”

“Could you tell me, Mr. Ford, what you’ve been doing in the hospital?” “Yes, sure. Me go, er, uh, P.T. nine o’cot, speech. . . two times. . read. . . wr. . . ripe, er, rike, er, write. . . practice. . . get-ting better.”

“And have you been going home on weekends?” “Why, yes. . . Thursday, er, er, er, no, er, Friday. . . Bar-ba-ra. . . wife. . . and, oh, car. . . drive. . . purnpike. . . you know. . . rest and. . . tee-vee.”

Halting speech, NON FLUENT

effortful

Comprehension relatively intact

Disordered syntax

Agrammatism

anomia

Telegraphic speech

Paraphasia

Philip Gorgan’s discussion with psychologist Howard Gardner

“What brings you to the hospital?” I asked the 72-year-old retired butcher 4 weeks after his admission to the hospital.“Boy, I’m sweating, I’m awful nervous, you know, once in a while I get caught up, I can’t mention the tarripoi, a month ago, quite a little, I’ve done a lot well, I impose a lot, while, on the other hand, you know what I mean, I have to run around, look it over, trebbin and all that sort of stuff.”

I attempted several times to break in, but was unable to do so against this relentlessly steady and rapid outflow. Finally, I put up my hand, rested it on Gorgan’s shoulder, and was able to gain a moment’s reprieve.

“Thank you, Mr. Gorgan. I want to ask you a few—” “Oh sure, go ahead, any old think you want. If I could I would. Oh, I’m taking the word the wrong way to say, all of the barbers here whenever they stop you it’s going around and around, if you know what I mean, that is tying and tying for repucer, repuceration, well, we were trying the best that we could while another time it was with the beds over there the same thing. . . .”

Fluent speech, logorrheaIncomprehensive

Neologism

More paraphasic errors :

If the word approximates the correct answer but is phonetically inaccurate (“plentil” for “pencil”; “grass is greel”) this is called literal or phonemic paraphasia.

The substitution of incorrect but related word (“pen“ for “pencil”; “grass is blue”) is termed verbal paraphasia or semantic substitution.

gibberish orjargon aphasia

The Wernicke–Geschwind Model ofLanguage and Aphasia

• Proposed by Wernicke. Later extended by Norman Geschwind at Boston University.

• The key anatomical elements in the system are: 1. Broca’s area, 2. Wernicke’s area, 3. Arcuate fasciculus (a bundle of axons connecting the two

cortical areas),4. Angular gyrus5. Sensory and motor areas involved in receiving and

producing language

17

3922

41,42

44,45

3,1,24,6

1819

General interpretative area, gnostic area, knowing area, tertiary association area

EXNER’S AREA

DEJERINE’S AREA

TYPES OF SPEECH• The main concern of the cortical areas that

represent language is using symbols for communication :

• Spoken and heard• Written and read,. or • Gestured and seen (in the case of sign language)

SPEAKING A READ WORD

SPEAKING A HEARD WORD

APHASIASType of Aphasia

Site of Brain Damage

Comprehension Speech Repetition Naming

Broca’s Inferior frontal gyrus

Preserved Non fluent,agrammatical

Impaired Impaired

Wernicke’s Posterior temporal lobe

Impaired Fluent, meaningless

Impaired Impaired

Conduction Arcuate fasciculus Preserved Fluent Impaired Impaired

Global Portions of temporal and frontal lobe

Impaired Scant, non fluent

Impaired Impaired

Anomic Deep temporal lobe

Preserved fluent except for word finding pauses

Preserved Impaired

Broca’s Aphasia• Damage to Broca’s area alone is not enough to produce Broca’s aphasia.

• Usually involves surrounding anterior perisylvian and insular cortex due to occlusion of the superior division of the middle cerebral artery

• Broca’s aphasia is not just an “expressive” or “motor” disorder and that it also may involve a comprehension deficit for function words and syntax

• Patients with Broca’s aphasia can be tearful, easily frustrated, and profoundly depressed

Wernicke’s Aphasia

• Damage to Wernicke’s area alone is not enough to produce Wernicke’s Aphasia

• An embolus to the inferior division of the middle cerebral artery, to the posterior temporal or angular branches in particular, is the most common etiology

Conduction Aphasia

the person speaks fluently and comprehends speech but cannot repeat what he or she has heard

Global Aphasia

• large “peri-Sylvian” lesions

• usually results from strokes thatinvolve the entire middle cerebral artery distribution in the left hemisphere

• Anomic aphasia is the single most common language disturbance seen in head trauma, metabolic encephalopathy, and Alzheimer’s disease

• The lesion sites can be anywhere within the left hemisphere language network, including the middle and inferior temporal gyri

Anomic aphasia

Type of Aphasia Characteristic NamingErrors

Broca’s aphasia

Wernicke’s aphasia

Conduction aphasia

Anomic aphasia

“Tssair”

“Stool” or “choss” (neologism)invented word

“Flair . . . no, swair . . . tair”

“I know what it is . . . I have a lot of them”

Characteristic responses of patients with lesions in various areas when shown a picture of a chair

Type of Aphasia

Site of Brain Damage

Comprehension

Speech Repetition Naming

Transcortical motor

Anterior or superior toBroca's area

Preserved Non fluent Preserved Impaired

Transcortical sensory

Surrounding Wernicke'sarea

Impaired Fluent Preserved Impaired

Isolation Frontal, parietal, temporal cortex sparing Broca’s and Wernicke’s area

Preserved unpurposeful Echolalia Impaired

Transcortical Motor Aphasia

• Damage often anterior and/or superior to Broca’s area

• Usually involves the anterior watershed zone between anterior and middle cerebral artery territories or the supplementary motor cortex in the territory of the anterior cerebral artery

• The features are similar to those of Broca’s aphasia, but repetition is intact

Transcortical Sensory Aphasia

• Cerebrovascular lesions (e.g., infarctions in the posterior watershed zone) and neoplasms that involve the temporoparietal cortex posterior to Wernicke’s area are the most common causes

Common area?

Type of Aphasia Site of Brain Damage

Comprehension Speech Repetition Naming

Pure word deafness

superior temporal gyrus

Impaired only for spoken language

Fluent Impaired Preserved

Pure word blindness(alexia without agraphia)

Posterior part of corpus callosum – splenium,Angular gyrus

Impaired only for reading

Fluent but unable to read aloud

Colour anomia

Preserved Preserved

The most common causes of pure word deafness are either bilateral or left sided middle cerebral artery (MCA) strokes affecting the superior temporal gyrus

APHEMIA• Acute onset of severely impaired fluency (often mutism)• Writing, reading, and comprehension are intact, and so this

is not a true aphasic syndrome.• Lesion at dominant frontal lobe

SUBCORTICAL APHASIA• Dominant thalamus lesions• Dominant striatocapsular lesions• The resulting syndromes contain combinations of deficits in

the various aspects of language but rarely fit the specific patterns described earlier in Table

Aphasia in Bilinguals • In children who learn two languages early in life, only a single area

is involved with both

• If the person learned two languages at the same time to equivalent levels of fluency, a lesion will probably produce similar deficits in both languages

• If the languages were learned at different times in life, it is likely that one language will be affected more than the other. The language learned more fluently and earlier in life tends to be relatively more preserved.

• The implication is that the second language may make use of different, although overlapping, populations of neurons from those used by the first

• American Sign Language has all the components (grammar, syntax and emotional tone) of spoken and heard language• Ursula Bellugi and her colleagues at the Salk Institute

examined the cortical localization of sign language abilities in patients who had suffered lesions of either the left or right hemisphere.• There are cases analogous to Broca’s aphasia in which

comprehension is good but the ability to “speak” through sign language is severely impaired• There are also sign language versions of Wernicke’s aphasia in

which the patient signs fluently but with many mistakes while also having difficulty comprehending the signing of others• Patients with lesions in approximately the same areas in the

right hemisphere did not have such signing "aphasias."

APHASIA IN DEAF

Patient with signing deficit we arrived In Jerusalem and stayed there

• Lateralization of language area has given rise to the misleading idea that one hemisphere is actually "dominant'' over the other.

• The true significance of lateralization lies in the efficient subdivision of complex functions between the hemispheres.

• According to current concept of complementary specialization, hemispheres are CATEGORIAL (sequential analytic processes) and REPRESENTATIONAL (for visuospatial relations)

Lateralization in the Brain

Hemispheric Control of Speech in

Relation to Handedness

A language disturbance that occurs after a right hemisphere lesion in a right hander is called CROSSED APHASIA

Search for Anatomical Differences between the Right and Left

Hemispheres• In the nineteenth century, there were reports of anatomical

differences between the two hemispheres

• Geschwind and Walter Levitsky found that in about 65% of the brains (based on measurements of 100 brain) , the left planum temporale (a part of Wernicke’s area on the superior surface of the temporal lobe) was larger than the right

• The asymmetry in this area is seen even in the human fetus, suggesting that it is not a developmental consequence. Indeed, speech became dominant in the left hemisphere because of a pre-existing size difference

• Other studies found that a portion of Broca’s area also tends to be larger in the left hemisphere.

• At present, it appears there may be some correlation between the asymmetric sizes of Broca’s area and the planum temporale with the hemisphere dominant for language, but the correlation is not strong enough to allow one to predict the language-dominant hemisphere from anatomical measurements alone.

• The brain region that presently appears to best predict which hemisphere is dominant for language is the insula, which is the cerebral cortex within the lateral sulcus that is between the temporal and parietal lobes

The insula, also called insular cortex, lies within the lateral sulcusbetween the temporal and parietal lobes

The Role of the Right Hemisphere

• Language deficits often do occur following damage to the right hemisphere.

• The most obvious effect of such lesions is a loss of the normal rhythm, stress and tonal variation of speech called prosody that impart additional meaning to verbal communication

• Sometimes translated as "accent," the Greek word prosodias refers to setting of words to music

• For example: “He is clever.” and “He is clever?” contain an identical word choice and syntax but convey vastly different messages because of differences in the intonation and stress with which the statements are uttered.

• Damage to perisylvian areas in the right hemisphere can interfere with speech prosody and can lead to syndromes of aprosodia.

• Damage to right hemisphere regions corresponding to Wernicke’s area can selectively impair decoding of speech prosody

• Damage to right hemisphere regions corresponding to Broca’s area yields a greater impairment in the ability to introduce meaning appropriate prosody into spoken language

• The latter deficit is the most common type of aprosodia identified in clinical practice. Patients with this type of aprosodia give the mistaken impression of being depressed or indifferent

• A 76-year-old man has a stroke that severely impairs his speech. Which area of his brain is most likely damaged?

A) Primary motor cortexB) Premotor areaC) Broca’s areaD) Cerebellum

Guyton and Hall Physiology Review 3ed, Unit IX, Q1

C) Broca’s area is a region of the premotor area of one hemisphere (usually the left). Damage to Broca’s area does not prevent a person from vocalizing but makes it impossible to speak whole words

• Lesions of which area of the brain would have the most devastating effect on verbal and symbolic intelligence?

A) HippocampusB) AmygdalaC) Wernicke’s area on the non dominant side of the brainD) Broca’s areaE) Wernicke’s area on the dominant side of the brain


E) The somatic, visual, and auditory association areas all meet one another at the junction of the parietal, temporal, and occipital lobes. This area is known as Wernicke’s area.

• Which structure serves to connect Wernicke’s area to Broca’s area in the cerebral cortex?

A) Arcuate fasciculusB) Lateral lemniscusC) Medial longitudinal fasciculusD) Anterior commissureE) Internal capsule


A) The connection between Wernicke’s area and Broca’s area in made by the arcuate fasciculus

• A lesion in Wernicke’s cortical area in the dominant hemisphere is most likely to produce which symptoms?

A) Impaired language skillsB) Impaired motor skillsC) Inability to form new memoriesD) Inability to plan future movementsE) Reduced cerebellar activityF) Reduced cerebral cortex activity


A) Wernicke’s cortical area is the major brain area for language comprehension

• Damage to which brain area leads to the inability to comprehend the written or the spoken word?

A) Insular cortex on the dominant side of the brainB) Anterior occipital lobeC) Junction of the parietal, temporal, and occipital lobesD) Medial portion of the precentral gyrusE) Most anterior portion of the temporal lobe


C) The junction of the parietal, temporal, and occipital lobe is commonly referred to as Wernicke’s area

• A person who has had a traumatic brain injury seems to be able to understand the written and spoken word but cannot create the correct sounds to be able to speak a word that is recognizable. This person most likely has damage to which area of the brain?

A) Wernicke’s areaB) Broca’s areaC) Angular gyrusD) Dentate nucleusE) Prefrontal lobe


B) Damage to Broca’s area leads to motor aphasia, or the inability to form words correctly.

• A patient with a stroke involving the nondominant temporal lobe would have impairment of which of the following aspects of their language function?

A) Fluency B) Prosody C) Repetition D) Naming E) Reading

Basic clinical neuroscience 3ed, Paul A Young, Pg. 224

B) Prosody is the rhythm and intonation of speech and is located in the nondominant hemisphere

• A 65-year-old male patient is admitted to the hospital with a parietal lobe haemorrhage on the dominant side of the brain. The patient speaks slowly, and his articulation is very poor consisting mainly of nonsensical phrases that are meaningless to the observer. The patient is aware that his speech is abnormal and continues to attempt the intended meaning by repeated reiterations without success. The stroke damaged what structure?

A) Inferior frontal gyrusB) Superior parietal lobuleC) Middle temporal gyrusD) Superior frontal gyrusE) Inferior parietal lobule

Basic clinical neuroscience 3ed, Paul A Young, Pg. 224

E) Conduction aphasia is associated with a lesion in the anterior part of the inferior parietal lobule (the supramarginal gyrus) and the adjacent part of the superior temporal gyrus in the dominant hemisphere

• A patient presents with a sudden inability to comprehend speech and uses nonsensical words and sentences. The clinician immediately suspects an infarct in a branch of what artery?

A. Anterior communicating artery.B. Basilar artery.C. Posterior cerebral artery.D. Middle cerebral artery.E. Anterior choroidal artery.

Lippincott’s Illustrated Reviews : Neuroscience, pg 169

D) The inferior branch middle cerebral artery supplies the lateral surface of the brain where the Wernicke area is located.While superior branch of middle cerebral artery supplies to Broca’s area

• The term language refers to:

a) To understand the spoken wordb) To understand the printed wordsc) To express ideas in speechd) All of the above

Comprehensive MCQs in Human Physiology, 2ed, AK Jain, ch. 105

• The brain centre/area involved in spoken speech are ALL EXCEPT:

a) Primary auditory centreb) Auditory psychic centrec) Wernicke’s aread) Dejerine area


• Which of the following is a sensory speech centre

a) Broca’s areab) Exner’s areac) Dejerine aread) Arcuate fasciculus


• NOT TRUE about Broca’s area

a) Present bilaterally in brainb) Also called as Broadmann’s area 44c) Projects the vocalization pattern to the motor cortexd) Present in inferior frontal gyrus


• The brain area that process the information from Broca’s area into detailed and coordinated pattern to produce written speech is:

a) Wernicke’s areab) Dejerine areac) Exner’s aread) All of the above


• When a person wishes to speak a certain thought, where does the thought originate

a) Broca’s areab) Posterior end of superior temporal gyrusc) Supramarginal gyrusd) Facial region of motor cortex


• Which of the following is INCORRECTLY matched

a) Damage to the parietal lobe of the representational hemisphere : unilateral inattention and neglect

b) Damage to the angular gyrus in the categorial hemisphere : non fluent aphasia

c) Damage to broca’s area in the categorial hemisphere : slow speech

d) Damage to the mammillary bodies : loss of the recent memory


• Pure word blindness occurs in lesion of:

a) Superior temporal gyrusb) Inferior temporal gyrusc) Middle temporal gyrusd) Angular gyrus


Parallel language pathways. Current models of language processing emphasizemultiple streams of processing

two dorsal pathways

a ventral pathway

One dorsal pathway (blue) connects the superior temporal gyrus (Wernicke’s and auditory areas) with premotor cortex and is involved in speech production and repeating words

The other dorsal pathway (green) connects the superior temporal gyrus with Broca’s area and is thought to be involved in processing complex syntactic structure—that is, the analysis of words arranged according to a grammar system

The ventral stream (red) takes the sounds of speech and extracts their meaning

Adapted from Berwick et al., 2013, Fig. 2

REFERENCES 1. Neuroscience, Exploring the Brain, 4ed, Wolters kluver 2. Neuroscience, 5ed, Sinauer Associates, Inc3. Neurophysiology, a conceptual approach, 5ed4. Lippincotts illustrated reviews neuroscience5. Basic clinical neuroscience, 3ed6. Adam and Victor’s principle of neurology 10ed7. Harrison’s Neurology in clinical medicine 3ed8. Guyton and Hall Physiology 13ed9. Guyton and Hall Physiology Review 3ed10. Ganong’s physiology 24ed11. A K Jain’s comprehensive mcqs in human physiology 2ed

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Speech disorders

Health & Medicine