language and speech physiology ppt for medical students

1. .
LANGUAGE
Language and Speech
Department of Physiology
Mahatma Gandhi Medical college & Hospital, Jaipur
• Language function depends on one cerebral
hemisphere than other.
• Dominant hemisphere
• It is related to Handedness
• In 95% of right handed persons, Left hemisphere is
dominant
• In 70% 0f left handed persons ,left hemisphere is
dominant
LANGUAGE
• In 15% of left handed persons right hemisphere is
dominant
• In rest of 15% left handers no clear lateralization is
found
• So 95% of population have left cerebral dominance
• Dominant hemisphere is also known as Categorical
hemisphere
LANGUAGE
• Dominant hemisphere has prominent Wernick,s area:
planum Temporale
• Other hemisphere is known as Non categorical or
representational hemisphere
• Responsible for visuo spatial relations
• Language : definition:
• Areas : Wernicke’s area-General
interpretation area
• Broca’s area--motor speech area
Cerebrum
• Largestportion of brain (80%
mass).
• Responsible for higher mental
functions.
• Corpus callosum:
• Major tract of axons that
functionally interconnects
right and left cerebral
hemispheres.
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Figure 8-6

2. .
• Both are connected by Arcuate fasciculus
• Exners area- Motor Writing area
• Speech articulation area in the Insula of the motor
cortex
• Angular gyrus behind Wernicke’s area process
information from words
• Visual cortex
• Auditory cortex
• All other somatic information
Mechanism
• Processing of sensory information
• Input to Wernicke’s area
• Via Arcuate fasciculus to Broca’s area or Motor
writing area
• Sequencing
• Excitation of respective areas of Primary motor
cortex controlling the respective cranial nerve nuclei
and spinal motor neurons
• Motor nerves and effecter muscles
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• All other somatic information
• Motor nerves and effecter muscles

3. .
Disorders
• Aphasias : Abnormalities of language functions that
Aphasias
Fluent aphasia:
• Aphasias : Abnormalities of language functions that
are not due to defects of vision or hearing or to
motor paralysis
• Caused by lesions in Categorical hemisphere
• Due to embolism or thrombosis of cerebral vessels
• Fluent
• Non fluent
• Anomic
Fluent aphasia:
• Lesion in Wernicke’s area
• Speech is normal
• Some times patient talks excessively
• Full of jargons and neologism with little sense
• Patient fails to comprehend the meaning of spoken or
written words
• Motor part of speech normal
Aphasias
• Conduction aphasia: Fluent aphasia
• Patient can speak relatively well and have good
auditory understanding but can not put words
together or conjure up words
• Due to lesions in and around auditory cortex
• Lesions of Angular gyrus: in categorical hemisphere;
Speech is normal, understanding auditory
information is normal
Aphasias
• Difficulty in understanding written words & pictures
• Visual information is not processed and transmitted
to Wernicke’s area (Anomic aphasia)
• Non-fluent aphasia:
• Lesions in Broca’s area
• Speech is slow and words are hard to utter
• Only limited words can be spoken to express
meaning and emotions
Aphasias
• Global aphasia: when more than one form of
aphasia: involves both receptive and expressive
functions
• Speech is scanty and nonfluent
• Writing is abnormal in all form of aphasias in
which speech is abnormal
• Lesions in representational hemisphere also
causes defect:
• Impair ability to tell a story or make a joke
Aphasias
• Fails to understand the joke
• Sensory aphasias :
• Word blindness
• Word deafness
• Stuttering : associated with right cerebral
dominance with wide spread over activity of
cerebral cortex including supplementary motor
area and cerebellum
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• Impair ability to tell a story or make a joke area and cerebellum

4. .
• Dyslexia : Impaired ability to learn to read
• More common in left handers
Aphasias
• Classificationby Sir Henry Head: English Neurologist
• More common in left handers • Classificationby Sir Henry Head: English Neurologist
• 1. Verbal defects:
- Power to express an idea in wordsis practically lost
-Pt. can utter a few words
-with less severe defects-wordsare mispronounced but
-sentencesare well constructed
-Readingis difficult and writingis defective or
impossible
-Patients understandsprinted or oral commands
• 2.Syntectical defects: Agrammatism,
Jargon Dysphasia
- Patient is talkative but speaks in Jargons
- Individual words are properly pronounced
but sentences are badly constructed
- Ability to read aloud is impaired
Ordinary conversation is defective
• 3. Nominal defects(Aphasia)
• Patient has difficulty in finding right words
to express the meaning or naming well known
objects
Uses descriptive phrases in substitution
fails to carry out simple arithmatic exercises and
confuse value of coins
• 4. Sementic defects:
• Articulation is nearly normal
• Can name objects
• Understand individual words and few sentences
• General meaning of what he hears is defective
• Fails to follow his own utterances to an intelligent
conclusion as if forgotten what he has to say
• Fails to grasp the meaning of picture or joke
Fails to comprehend the significance of what he sees or
hears.
Speech tends to be short and jerky
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5. .
Anarthria (Dysarthria)
• Due to paralysis of muscles of articulation
• Due to paralysis of muscles of articulation
• Internal speech is unaffected
Agraphia: Inability to write
• May occur with visual agnosia
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