PHYSIOLOGY OF SPEECH · 2019-04-04 · Nonfluent speech, disturbed understanding and speech...
Transcript of PHYSIOLOGY OF SPEECH · 2019-04-04 · Nonfluent speech, disturbed understanding and speech...
PHYSIOLOGY
OF
SPEECH
Paul Broca1864 identified the area for speech production
BROCA APHASIA
Karl Wernicke1874 identified the area for speech understanding
WERNICKE APHASIA
Broca areaspeech coding to articulation form„GRAMMAR MACHINE”
Inferior frontal gyrus
Wernicke area speech decoding and understanding of its meaning „LEXICON”
temporal superior gyrus
Temporal gyrus
Fasciculus arcuatusPrimary motor cortex
KEY AREAS IN THE BRAIN AND SPEECH FUNCTIONS
Frontal inferior gyrus
superior temporal gyrus
Occipital lobe
Fasciculus arcuatusPrimary motor cortex
Gyrus angularis
Broca areaspeech coding to articulation form„GRAMMAR MACHINE”
Wernicke area speech decoding and understanding of its meaning „LEXICON”
KEY AREAS IN THE BRAIN AND SPEECH FUNCTIONS
BRAIN LESION IN PATIENT WITH
BROCA´S AFASIA
BROCA´S APHASIA
• An example of agrammatic speech:
• Ah ... Monday ... ah, Dad and Paul Haney [himself] and
Dad ... hospital. Two .. .ah, doctors ... and ah ... thirty
minutes .. .and yes ... ah ... hospital. And, er,
Wednesday ... nine o'clock. And er Thursday, ten o'clock
.. .doctors. Two doctors ... and ah ... teeth. Yeah, ... fine.
• Another example:
M.E. Cinderella...poor...um 'dopted her...scrubbed floor,
um, tidy...poor, um...'dopted...Si-sisters and
mother...ball. Ball, prince um, shoe...
A photo of the excised brain of a Wernicke's patient http://www.ling.upenn.edu/courses/Fall_2001/ling001/neurology.html
WERNICKE´S APHASIA
• The patient in the passage below is trying to
describe a picture of a child taking a cookie.
• C.B. Uh, well this is the ... the /dodu/ of this. This
and this and this and this. These things going in
there like that. This is /sen/ things here. This one
here, these two things here. And the other one
here, back in this one, this one /gesh/ look at this
one.
A set of tomographic pictures of a different Wernicke's syndrome brain,
showing a series of horizontal slices. The front of the head is towards the top,
and the dominant (left) side is on the right, so it is as if we are looking at the
brain from the bottom:
http://www.ling.upenn.edu/courses/Fall_2001/ling001/neurology.html
CLASSIFICATION OF APHASIAS
Conductive aphasiaFluent speech, understands, but barely
repeats spoken and written words,
disturbed naming
Damaged connection between the two key
speech areas (Wernicke a Broca)
Global aphasiaNonfluent speech, disturbed understanding
and speech production as a consequence
Of extensive damage in the left hemisphere
(area supplied by arteria cerebri media)
Subcortical aphasiaDisturbed concentration and choice of
Information, speeking in accordance
with breething. Lesion of left thalamic
nuclei
Anomic aphasiaFluent speech, normal
Understanding and
conversation,
Inablity to name people
and objects
Lesion of left angular
gyrus
SPEECH AND ANATOMIC ASSYMETRY
PLANUM
TEMPORALE
Temporal plane in
superior temporal
lobe is identical with
Wernicke area
65% of people have
larger left planum
temporale
(10% right)
POSITRONE EMISSION
TOMOGRAPHY (PET)
Injection of
radioactive
2-DG, it is
„ingested“ by
metabolically
active neurons -
phosphorylation
– emission of
positrones –
level of activity
Positron Emission Tomography (PET)Brain metabolic activity during speech
Activity of different brain areas during sensory input (primary and secondary visual and auditory cortex)Basal activity subtracted
Repeating words after subtracting of listening to words = speaking words
Generating verbs to nouns (bread - eat) speaking words subtracted
FUNCTIONAL ASSYMETRY
OF
BRAIN HEMISPHERES
Speech representation (%)
handedness No Left Bilateral right
righthanded 140 96 0 4
lefthanded 122 70 15 15
(Rasmussen a Milner, 1977) Wada test
handedness (EHI)
N=326
Right hemispheric dominance for speech (%)
righthanded 75 až 100 10
Ambidexters -75 až 75 43
lefthanded -75 až -100 54
(Knecht a spol., 2000) Functional transcranial Doppler sonography
SPEECH AND LATERALITY
Patient is fixing the pointIn the middle of the picture
SaysLAURA…
KnowsPETER...
Lefthemisphere
righthemisphere
Recognizesfeatures
Recognizeswhole picture
LEFT HEMISPHERE
Spoken and perceived speech is percieved as written without intonation
Disturbance of non-speech perception, does not recognize people according to his/her voice
Verbal memory(does not remember faces, remembers home address)
RIGHT HEMISPHERE
Distinguishes non-speech sounds (melodies, sound of the wind... recognises people according to his/her voice)
Disturbance of perceived and produced speech
Spatial memory (does not rememeber the address, but rememebers the way)
SPLIT BRAIN
LEFT HEMISPHERE RIGHT HEMISPHERE
LEFT HEMISPHERE
SYSTEMIC
SYSTEMIZING
RIGHT HEMISPHERE
EMOTIONAL
EMPHATIZING
GENDER DIFFERENCES IN BRAIN LATERALITY AND FUNCTIONAL SPECIALIZATION OF BRAIN HEMISPHERES