For what percentage of people is language lateralized to th left hemisphere?
90% of right handers
60% of left handers (the other 40% - half are left dominant and the other are bilateral)
What are the 3 overlappin gocmponents of language?
Given what we know about sign language, what are the "language regions" of the brain actually specizlied in?
more of a symbolic representation of communication as opposed to words
What are the three rules that define a language?
grammar: define symbol use
syntax: the organization of the symbols
prosody: allow emotional emphasis via changes in pitch intensity and rhythm
Where does the primary language pathway begin and end?
starts with auditory and visual cortices sending information to Wernicke's area
the arcuate fasciculus takes information from Wernicke's to Broca's area
output from Broca's area goes to the motor cortex for initiateion of the complex muscle movements necsesary for speech
Where is Gershwin's territory and what function is it associated with?
It's in the inferior parietal lobe
receives both audiotry and visual info
involved with recognition and labelling of items
While the left brain is usually the dominant hemisphere for language, what other major function is usually mediated by the right hemisphere?
THe right hemisphere equivalent of Wernicke's area is responsible for what aspect of speech?
What is the fundamental pitch of a perons' voice determined by?
Gender, size and age
all these things affect the side of the vocal folds, which alters resonance
HOw are different voharwles produced?
by altering the shape of the vocal tract by moveing the tounge, pharynx, and vocal folds
How are different consonants generated?
closing and opening of the focal folds and changing the shape of the mouth
About how many speech sounds can humans generate? What are these called?
there are about 200
these are called phones
What is the term for the perception of phones?
How many words does the average person have in their working memory and how many words can the average person recognize?
working vocabulary = 10,000 words (about double for doctors)
What are neurogenic speech disorders?
They're speech disorders defined as an inability to exchange information with others due to a NERVOUS SYSTEM IMPAIRMENT
How are aphasias categorized?
fluent or nonfluent
(further by auditory and verbal comrpehension and verbal and graphic expression)
Describe a fluent aphasia
it's when th epatient has no problem generating speech, the speech just is conprehensivle and they can't understand the speech of others
Describe a nonfluent aphasia
patient can comprehens things fine, but can't produce speech
What is receptive aphasia?
it's wernicke's aphasia
it is characterized by a severe deficit in auditory and written comprehension
they have fluid speech, but it's complete nonsense
usually not frustrating bec. the patient doesn't realize it
What is a conduction aphasia?
it's a fluent aphasia
It's an issue with the arcuiate fasciculus connection between Broca's and Wernicke's
they ahve good comprehension and aare able to produce speech, but have lots of pauses and gaps as they try to figure out the words they want
What happens in an expressive aphasia?
this is Broca's aphasia
they can comprehend perfectly, but you have impaired verbal and oral expression - especially with organization and control of speech.
super frustrating because they can know what they want to say and just can't get the words out
What happens in a global aphasia?
when you have large areas of damage and deficits in both comprehension and expression
(usually with other deficits as well)
What is aprosody?
occurs with right sided equivalent of Wernicke's and Broca's aphasias
you lose prosody of your own speech and you can't comprehend the prosody of other people's speech
What happens in an apraxia?
It's an inability to translate speech plans into motor output (usually in children without any obvious issue on MRI)
the most obvious symptom is the inability to string phones together in the correct order to make a word and they'll say the word differently every time - making different mistakes
What happens in a dysarthria?
it's a lack of motor control over the movements necessary for production of speech
usually from damage in the CNS or PNS - not the larynx of vocal folds