specific functions on specific to one side of the cortex rather than bilateral
brain injuries “split brain” patients imaging studies
left hemisphere◦ analytical abilities◦ quantitative skills◦ language
right hemisphere◦ music◦ spatial abilities◦ artistic abilities◦ emotions◦ facial recognition
most well studied lateralized behavior◦ 95% of right handed have
speech on left◦ 70% of left handed have
speech on left
aphasia – language deficit that cannot be attributed to motor, motivational, sensory or other explanations
characterized by broken halted speech, absence of prosody
non-fluent aphasia
Frontal lobe
agrammatism◦ difficulty in comprehending or properly employing
grammatical devices, such as verb endings and word order.
anomia◦ Difficulty in finding (remembering) appropriate word
articulation◦ difficulty mispronouncing words
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Can’t just be motor or it wouldn’t be an aphasia
Grammatical issues with connecting words
The lion was killed by the leopard.
lion killed leopard.
Can’t just be motor or it wouldn’t be an aphasia
Grammatical issues with connecting words
Non-fluent aphasia
Comprehension – fairly good; ability to read – fairly good
Copyright © Allyn & Bacon 2007
Part of the Boston Diagnostic Aphasia Test
Copyright © Allyn & Bacon 2007
deficits observed depend on individual as well as where in this region damage occurs…◦ fmri studies…..
◦ INSULAR CORTEX – speech articulation?◦ apraxia?
Copyright © Allyn & Bacon 2007
fluid aphasia, deficits appear to be in comprehension; words are nonsensical
comprehension – poor reading ability - poor
recognition of spoken words comprehension of meaning of words ability to convert thoughts into words
How do we test comprehension in someone that may have Wernicke’s Aphasia?
surgical requirements
injection of sodium amytal or sodium amobarbital – anesthetic
used to determine hemisphere important for speech
split brain surgery
initially – ◦ odd behaviors -
◦ subsequently – only can really tell by experimental manipulations in the lab
◦ Julian Jaynes – “Breakdown of the Bicameral Mind”
Functional brain imaging◦ fMRI or PET used to see which half is active
when doing a language test
Copyright © 2006 by Allyn and Bacon
Copyright © 2006 by Allyn and Bacon
apraxia (of speech)- speech disorder with difficulty speaking correctly; not due to weakness or paralysis of speech muscles (NIDCD); complex motor commands
acquired◦ most typically in adults after brain damage
developmental◦ appears present from birth◦ affects boys more than girls◦ other names – verbal dyspraxia, articulatory
apraxia, childood speech apraxia◦ different than developmental delay of speech
cause or causes unknown may be related to language development may be neurological disorder no specific lesions or imaging studies
helpful family history of communication disorders
or learning disabilities
difficulty putting sounds and syllables together in correct order
longer words more difficult than short inconsistent speech (say word and then
unable) children – comprehension much better than
expression
severity can vary widely
http://www.youtube.com/watch?v=szjfC9K190U&feature=fvsr
http://www.youtube.com/watch?v=XNB0ihI2srQ&feature=related
genetic component family studies twin studies complex in terms of genes complex in terms of etiology complex in terms of traits
◦ can include phonological, auditory, motor, visual deficits which make reading even more difficult