Physiology of Speech .pdf

Physiology of Speech Student Handout

1. PHYSIOLOGY OF
SPEECH
DR. SARAN AJAY
DEPT. OF PHYSIOLOGY, GMCM
2

2. Languageisuniquelyhumanandarguablyourgreatestskillandour
highestachievement.Humansarenottheonlyspeciestocommunicate.
Passerinebirdsattractmateswithsongs,beescodethedistanceand
directiontohoneybydancing,andmonkeyssignaladesireforsexual
contactorfearattheapproachofanenemywithcoosandgrunts.
Eric Kandel
With
languageweaccomplishalloftheaboveandmore.Weuselanguageto
provideinformationandexpressouremotions,tocommentonthepastand
future,andcreatefictionandpoetry.Noanimalhasacommunication
systemthatparallelshumanlanguageeitherinformorinfunction.
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3. Eric R. Kandel Nobel Prize in Physiology
and Medicine 2000
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4. DEPT. OF PHYSIOLOGY, GMCM 5
Specific Learning Objectives
•Introduction
•Speech Areas
•Concept of Dominant Hemisphere
•Development of Speech
•Production of Speech
•Disorders of Speech
•Lesions in the Representational Hemisphere
DEPT. OF PHYSIOLOGY, GMCM

5. Speech
Humanfacilitybywhichthoughtprocessesare
symbolicallyexpressedaslanguageeitherinverbal
orwrittencomponents.
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6. •A higher cognitive function exclusive for human
beings.
•An effective and rapid vehicle for communication.
•Speech is incomplete without language in man.
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7. Language
•A setofconventionalsignsandsymbolsthat
conveysameaning.
•Fundamentalbaseofintelligence.
•Akeypartofhumanculture.
•Languageandspeechabsentinanimals.
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8. DEPT. OF PHYSIOLOGY, GMCM 9

9. Speech is the mode,
languagethe means,
and soundthe media.
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10. Two aspects of communication
Language Input Language Output
SENSORY MOTOR
Visual
Auditory
Proprioceptive
Impulses
Spokenlanguage
Writtenlanguage
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11. •Sensoryaspectofspeechistheabilitytounderstand
whatiswrittenandspoken.
•Motoraspectofspeechistheabilitytospeakand
write.
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12. DEPT. OF PHYSIOLOGY, GMCM 13
Specific Learning Objectives
•Introduction
•Speech Areas
•Concept of Dominant Hemisphere
•Development of Speech
•Production of Speech
•Disorders of Speech
•Lesions in the Representational Hemisphere
DEPT. OF PHYSIOLOGY, GMCM

13. Speech Areas
Sensory
Speech Areas
Motor
Speech Areas
Wernicke’s Area
Dejerine’sArea
Broca’s Area
Exner’s Writing Area
Arcuate Fasciculus
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14. 1. Wernicke’s Area (Area 22) -Sensory
•Posterior end of superior temporal gyrus in dominant
hemisphere.
•Transforms auditory and visual input into neural words
and project into Broca’s area through arcuate fasciculus.
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15. •Essential for comprehension, recognition and
construction of words and language.
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16. Wernicke’s Area
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17. 2. Broca’s Area (Area 44, 45) –Motor
•Inthefrontallobe,infrontofinferiorendofmotor
cortex.
•ProcesstheinformationfromWernicke’sareaintoa
detailedandcoordinatedpatternforvocalization.
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18. •Itisthenprojectedtomotorcortexwhichinitiatesthe
movementofthosestructuresthatisresponsiblefor
theproductionofvoiceandarticulationofspeech.
•i.e.,activationofvocalcordsandmovementsofmouth
andtonguefinallythroughthecorticobulbartracts.
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19. Broca’s Area
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20. Arcuatefasciculusisabundleofaxonsthatconnects
Wernicke’sareawithBroca’sarea.
Arcuate Fasciculus
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21. Arcuate Fasciculus
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22. 3. Dejerine area (Area 39) – Sensory
•IntheangulargyrusbehindWernicke’sarea,anteriorto
visualarea.
•Involvedingenerationofthoughtsandideasin
responsetowrittenlanguage.
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23. DEPT. OF PHYSIOLOGY, GMCM 24

24. ExnersArea (Motor Writing Area) -Motor
•Inthemiddlefrontalgyrusinpremotorcortex
•ProcessinformationfromBroca’sareaandalongwith
motorcortexinitiatesmusclemovementsofhands
andfingerstoproducewrittenspeech.
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25. DEPT. OF PHYSIOLOGY, GMCM 26

26. DEPT. OF PHYSIOLOGY, GMCM 27
Specific Learning Objectives
•Introduction
•Speech Areas
•Concept of Dominant Hemisphere
•Development of Speech
•Production of Speech
•Disorders of Speech
•Lesions in the Representational Hemisphere
DEPT. OF PHYSIOLOGY, GMCM

27. Concept of dominant hemisphere for language
•Humanlanguagefunctiondependmoreonone
cerebralhemispherethantheother.
•Thishemispherehasbeencalledthedominant
hemisphere.
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28. However, the other hemisphere is specialized (dominant) in
•Spatial relations between person and their surroundings
•Identification of objects
•Recognition of faces.
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29. •Due to this, dominant hemisphere is now referred to as
Categorical hemisphere.
•Non-dominant hemisphere is called Representational
hemisphere.
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30. In 96%of right-handed individual
•Leftis the categorical hemisphere
In 70%of left-handed individual
•Leftis the categorical hemisphere
•15%-right hemisphere is dominant
•Remaining 15%-no clear lateralization
➔In ~95%of people, left hemisphere –categorical.
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31. DEPT. OF PHYSIOLOGY, GMCM 32
Specific Learning Objectives
•Introduction
•Speech Areas
•Concept of Dominant Hemisphere
•Development of Speech
•Production of Speech
•Disorders of Speech
•Lesions in the Representational Hemisphere
DEPT. OF PHYSIOLOGY, GMCM

32. Audition –primary initiation
•First step of learning language is by hearing.
•Auditory center develops first and is myelinated earlier.
•Deafness in early childhood results in loss of speech.
•Speech then trained by lip language.
•Written speech develops when the child starts learning.
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33. Twostages
1.Associationofwordswithobjectsandpersons
around.
2.Developmentofneuronalcircuitsbetweenthese
sensoryareasandmotorareasforspeech.
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34. DEPT. OF PHYSIOLOGY, GMCM 35
Specific Learning Objectives
•Introduction
•Speech Areas
•Concept of Dominant Hemisphere
•Development of Speech
•Production of Speech
•Disorders of Speech
•Lesions in the Representational Hemisphere
DEPT. OF PHYSIOLOGY, GMCM

35. Production of Speech
Complex and well coordinated neurophysiological pattern of
activity.
1.Choice of appropriate symbol
2.Execution of speech
•Spoken word
•Written word
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36. Neurophysiology of Speech
•Under the overall control of cortex
•Production of speech involves:
•Pyramidal and extrapyramidal system
•Cerebellum
•Hypothalamus
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37. Spoken words
Primary Auditory centre
Association area
WERNICKE’ S
AREA
Written words
Primary Visual area
Association area
BROCA’S AREA
Motor area for
writing-Exner’s area
VISUAL WORD
CENTRE
AUDITORY WORD
CENTRE
Motor area for speech
OR
OR
Via Arcuate Fasciculus
SPOKEN SPEECH
WRITTEN SPEECH
via
Angular
gyrus
Receptive AreasExpressive Areas 38

38. DEPT. OF PHYSIOLOGY, GMCM 39

39. Execution of Spoken Speech
Requires perfect co-ordination of
1.Respiration
2.Phonation
3.Articulation
4.Resonation
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40. DEPT. OF PHYSIOLOGY, GMCM 41

41. DEPT. OF PHYSIOLOGY, GMCM 42

42. PHYSIOLOGY OF
SPEECH-2
DR. SARAN AJAY
DEPT. OF PHYSIOLOGY, GMCM
43

43. DEPT. OF PHYSIOLOGY, GMCM 44
Specific Learning Objectives
•Introduction
•Speech Areas
•Concept of Dominant Hemisphere
•Development of Speech
•Production of Speech
•Disorders of Speech
•Lesions in the Representational Hemisphere
DEPT. OF PHYSIOLOGY, GMCM

44. Speech Area Location Function Sensory/Motor
Wernicke’s Area Superior temporal
gyrus
Comprehension of visual
and auditory information
Sensory aspect
(written +spoken)
Broca’s Area In front of the inferior
motor cortex
Detailed and co-ordinated
pattern of vocalisation
Motor aspect
(spoken + written)
Dejerine Area In angular gyrus
behind Wernicke's
areas
Generation of thoughts
and ideas in response to
written language
Sensoryaspect
(written)
Exner’s Area Middle Frontal Gyrus
in Premotor
With Broca and motor
cortex initiates finger
movements
Motoraspect
(written)

45. Speechandlanguagedisordersmaybedividedintofour
categories
1.Aphasiaordysphasia
2.Disturbancesofspeechsecondarytootherglobal
disease
3.Dysarthria
4.Aphonia
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46. 1. Aphasia
Aphasiasareabnormalitiesoflanguagefunctionsthat
arenotduetodefectsofvisionorhearingortomotor
paralysis.
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47. Lossorimpairmentofproductionand/orcomprehension
ofspokenorwrittenlanguageduetoanacquiredlesionofthe
brain.
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48. •They are caused by lesions in the categorical hemisphere.
•Most common cause is embolism / thrombosis of cerebral
blood vessel.
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49. DEPT. OF PHYSIOLOGY, GMCM 50

50. Types of Aphasia
A.Fluent aphasia – Wernicke’s aphasia / Sensory
aphasia / Receptive aphasia
B.Non fluent aphasia / Motor aphasia / Broca’s aphasia
C.Global aphasia
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51. Wernicke’s Aphasia
•A type of fluent aphasia.
•Due to lesion in Wernicke’s area.
•Speech is fluent, increased verbal content, phrase length
more than 4-5 words
•Grammatical sentences
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52. Wernicke’s Area (22)
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53. •Sometimes talks excessively (logorrhea).
•Full of neologisms, jargon, paraphasiathat make little
sense.
•Poor comprehension and poor repetition.
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54. •Neologism–nonsensewordoraninventedword
•Jargon–extremeneologism
•Paraphasia–compensationforaforgottenword
usingdescriptivephase.
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55. DEPT. OF PHYSIOLOGY, GMCM 56
(165) Fluent Aphasia (Wernicke's Aphasia) –YouTube

56. Conduction aphasia
•Form of fluent aphasia.
•Lesion in the arcuate fasciculus
•Patients can speak relatively well but with word finding
difficulty
•Paraphasia, self correction, pauses.
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57. DEPT. OF PHYSIOLOGY, GMCM 58
Arcuate Fasciculus

58. •Good auditory comprehension.
•Characteristically, repetition is severely affected. .
•Writing is invariably impaired.
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59. DEPT. OF PHYSIOLOGY, GMCM 60
(165) Reel-Example: Conduction Aphasia 1 -YouTube

60. Non fluent aphasia/ Broca’s aphasia
•Lesion in Broca’s area
•Speech is non fluent, slow and words are hard to come by
•Decreased verbal content
•TelegraphicSpeech (<4 words)
•Agrammatical sentences
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61. DEPT. OF PHYSIOLOGY, GMCM 62
Broca’s Area (44, 45)

62. •Content words, no preposition or conjunction
•Defective formulation of word.
•Comprehension is normal.
•Repetition impaired
•Patient can be tearful, easily frustrated, depressed.
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63. DEPT. OF PHYSIOLOGY, GMCM 64
(165) Broca's Aphasia (Non-Fluent Aphasia) -YouTube

64. Anomic aphasia
•Difficultyinunderstandingwrittenlanguageorpicture.
•Namingdifficulty.
•Circumlocution–describefunctionnotname
•Duetolesionofangulargyrusincategorical
hemisphere.
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65. DEPT. OF PHYSIOLOGY, GMCM 66

66. Global aphasia
•Involvesbothreceptiveandexpressivefunctions.
•DuetocombinedlesionsofbothBroca’sand
Wernicke’sarea.
•Speechoutputisscantyandnonfluent.
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67. •Comprehensionimpaired.
•Severeimpairmentofallmodality–speaking,listening,
reading,writing.
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68. 2.Disturbances of speech secondary to other
global disease
•Diseasesthatgloballyaffecthighermental
function
•E.g.dementia,inwhichspeechandlanguage
functionsareimpairedaspartofthegeneralloss.
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69. 3. Dysarthria
•Defectinarticulationofspeech
•Intactmentalfunctionandcomprehensionofspokenand
writtenlanguage.
•Disorderofmusclesofarticulation,whichmaybedue
toflaccidorspasticparalysis.
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70. 4. Aphonia
Loss of voice due to disorder of larynx or its innervation.
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71. DEPT. OF PHYSIOLOGY, GMCM 72
Specific Learning Objectives
•Introduction
•Speech Areas
•Concept of Dominant Hemisphere
•Development of Speech
•Production of Speech
•Disorders of Speech
•Lesions in the Representational Hemisphere
DEPT. OF PHYSIOLOGY, GMCM

72. Lesionsinthecategoricalhemisphereproducelanguage
disorders,whereasextensivelesionsintherepresentational
hemispheredonot.*
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73. •However,lesionsintherepresentationalhemisphere
alsohaveeffectsinspeechandlanguage.
•Impairmentintheabilitytocomprehendthemeaningof
differencesininflectionandthe“color”ofspeech.
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74. •Otherthanspeech,thelesionsintherepresentational
hemisphereproduceastereognosis
•Theinabilitytoidentifyobjectsbyfeelingthem.
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75. •Thelesionsoftheinferiorparietallobule,aregioninthe
posteriorpartoftheparietallobe,causeunilateral
inattentionandneglect.
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76. DEPT. OF PHYSIOLOGY, GMCM 77
(165) Reel-Example: Hemineglect - YouTube

77. DEPT. OF PHYSIOLOGY, GMCM 78

78. Q
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79. 1.Write briefly -Aphasia. KUHS 2014
2.Physiological Basis -Fluent Aphasia KUHS 2012
3.The motor speech center is ________ area. KUHS 2022,
2018
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80. DEPT. OF PHYSIOLOGY, GMCM 81
Specific Learning Objectives
•Introduction
•Speech Areas
•Concept of Dominant Hemisphere
•Development of Speech
•Production of Speech
•Disorders of Speech
•Lesions in the Representational Hemisphere
DEPT. OF PHYSIOLOGY, GMCM

81. [email protected]
DEPT. OF PHYSIOLOGY, GMCM
1