Flashcards in Lecture 8 Deck (36):
What is language?
- a set of symbols and a set of rules
- Crossed across two types of modality and activity divided into either expressive or receptive
What are the 4 language functions?
- Auditory-verbal comprehension
- Speech: auditory expressive
- Reading: visual receptive
- Writing: visual expressive
How do we understand the brain regions involved in language?
- from the studies of stroke victims and brain imaging of normal individuals (PET or fMRI)
What is Broca's aphasia?
- also known as expressive aphasia/non-fluent aphasia
- results from damage to the interior left frontal lobe
- issues with speech production
What are the symptoms of Broca's aphasia?
- slow and laborious speech
- person can mostly comprehend the speech of others, but not fully
- impaired in speaking, but can still comprehend
What is the anatomical basis for Broca's aphasia?
- damage in inferior frontal lobe
- Need to have damage beyond the cortex
- need to have damage in the white matter (the myelin sheath) - damage to the caudate nucleus in basal ganglia can also produce this aphasia
What is wernicke's aphasia?
- issues with speech comprehension
- receptive or fluent aphasia
- principally an impairment in comprehension
What are the symptoms of wernicke's aphasia?
- poor speech comprehensions
- fluent, but meaningless speech
- patients are unaware of their comprehension deficit
What is the anatomical basis for Wernicke's aphasia? (neuropsych functioning)
- auditory association cortex of posterior superior temporal gyrus (recognizes sounds and words)
What is prosody?
- refers to variations in rhythm, pitch, and cadence that communicate information
- used to distinguish questions from statements
- prosody can communicate cues from statements
What is the anatomical basis for prosody?
- not disrupted for Wernicke's
- disrupted damage to the right hemisphere
In what hemisphere is prosody mediated by?
- The right hemisphere
Which aphasia is disrupted by prosody?
- Broca's lesions disrupt prosody because of the labor and disruption of speech
What is Pure alexia?
- refers to inability to read or alexia without agraphia
- writing is not impaired
- similar to word deafness
How is pure alexia produced?
- damage to the left visual cortex AND posterior end of the corpus callosum.
What part of the brain carries out pure alexia?
- word recognition carried out by right extrastriate cortex
- cannot reach the speech regions of the left hemisphere
How are pure alexia and aphasia related?
- they are related because the both have damage to the left side. The left hemisphere and the left visual cortex.
- Need to remember that both typically impair functioning in one particular area rather than all areas. Pure alexia impairs reading and not writing. Aphasia impairs production of speech or comprehension, however not both at the same time.
What is pure word deafness?
- inability to recognize spoken words with no impairment of hearing or understanding meaning
- can write and understand words perceived by lip reading and reading
- can recognize non-speech sounds like dog bark or car horn
What causes pure word deafness?
- focal damage to wernicke's area i.e. L posterior superior temporal gyrus
- disruption to white matter
- bilateral damage to primary auditory cortex
What does pure word deafness deal with?
- Deals with speech in Wernicke's area
What are the L and R hemispheres involved with in pure word deafness?
- LH: primarily involved in judging the timing of the components of rapidly changing complex sounds
- RH: is involved with judging more slowly changing components including memory
What is the most crucial aspect of speech?
- speech is timing not pitch
What are two types of brain injuries that can cause pure word deafness?
- disruption of auditory input to the superior temporal cortex
- damage to the superior temporal cortex
How are mirror neurons involved with pure word deafness?
- feedback from the motor neurons - neurons activated wither when we perform an action or see the action performed - may be able to help us understand the intention of others
What is the process of motor mirror neurons with pure word deafness?
- Hearing speech activates regions of the brain that control the production of speech
- mirror neurons are activated by sounds of words
- Investigators suggest that subvocal articulation facilitates speech recognition
- Activity from motor neurons and feedback from speech movements affect speech perception
What is damaged in transcortical sensory aphasia?
- impairment of word meaning results from damage to the posterior language area surrounding Wernicke's area in the border of the termporal, parietal, and occipital lobes
What is transcortical sensory aphasia?
- speech disorder that causes difficulty comprehending speech and producing meaningful spontaneous speech, but can repeat speech; damage to posterior language area
What is the difference in transcortical sensory aphasia and Wernicke's aphasia?
- can repeat and recognize words. This is different than WA
- this person would not be able to comprehend or produce meaningful speech on their own
True or False: Wernicke's aphasia is a combination of pure word deafness and transcortical sensory aphasia
What are the three major speech deficits produced by Broca's aphasia?
- articulation difficulties (speech apraxia)
What is agramatism?
- difficulty using grammatical constructions
- difficulty comprehending word order to decode meaning of a sentence
- does not understand grammar rules and how they glow in a sentence
What is anomia?
- word-finding difficulty
- problem locating the word in their network
- Tip of the tongue phenomemon: common everyday difficulty finding the correct word
- people with this issue showed loss of gray matter in the left insular cotex
What are articulation difficulties
- often altering the sequence of sounds
- able to recognize
What is speech apraxia?
- impairment in the ability to program movements of the tongue, lips, and throat that are required for proper sequence of speech sounds
What is the hierarchy of the Broca's aphasia impairments?
o Lowest: Damage to area of control of sequence of movements causes articulation difficulties
o Middle: damage to selection of particular programs for words-causes - anomia
o Highest: selection of grammatical order- agrammatism