Child aphasia & other disorders Brain & Language LING 411, NSCI 411/611 Harry Howard Tulane University
Come See a Movie With Thursday October 12 7:00 pm in Paterson Lounge Neuroscience Majors Psych Majors TUNA Members Cell Ma...
Q2 answers
Milestones <ul><li>[See Hoff 01:7] </li></ul>
Normal language development L2 is increasingly difficult 15y + foreign accent in L2 11-14y grammatical refinement & expans...
How lateralization develops <ul><li>Equipotentiality hypothesis (Lenneberg 1967) </li></ul><ul><ul><li>LH & RH have equal ...
Evidence from processing studies with children <ul><li>Molfese, Freeman & Palmero (1975) found that 10m showed same latera...
Evidence from childhood aphasia & brain injury prior to language <ul><li>Few children get aphasia </li></ul><ul><li>It inv...
Effect of LH lesion at age aphasiac symptoms persist (usually irreversible if more than 3-5m) 15y + aphasiac symptoms no l...
Conclusions LH dominant in 97% population 15y + LH becomes dominant (invariance) 11-14y LH takes over more responsibility,...
Basic processes in neurological development <ul><li>Neural plasticity </li></ul><ul><ul><li>Children’s brains are more  pl...
The critical/sensitive period <ul><li>It appears that there is a period during which children must be exposed to language ...
The genetics of language development <ul><li>It is a maturational process, the course and timing of which is determined by...
A story told by a 4.5y child with SLI <ul><li>The man got on the boat. He jump out the boat. He rocking the boat. He drop ...
Sentences produced by a 16y with SLI <ul><li>Then he went home and tell mother - his mother - tell what he doing that day....
Specific language impairment/ Developmental dysphasia <ul><li>Cognition </li></ul><ul><ul><li>normal, as measured by IQ te...
Language and other species  <ul><li>Primates </li></ul><ul><li>The birds & the bees </li></ul>
The origin of language <ul><li>Evolutionary psychology </li></ul><ul><li>Language is an adaptation </li></ul><ul><ul><li>M...
Next time <ul><li>I am away next week; you will see two videos </li></ul><ul><li>Bellugi et  al. &quot;Williams syndrome&q...
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D12 Child

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D12 Child

  1. 1. Child aphasia & other disorders Brain & Language LING 411, NSCI 411/611 Harry Howard Tulane University
  2. 2. Come See a Movie With Thursday October 12 7:00 pm in Paterson Lounge Neuroscience Majors Psych Majors TUNA Members Cell Majors The Tulane University Neuroscience Association is hosting a showing of the film The Jacket . Come enjoy some food with us while we watch.
  3. 3. Q2 answers
  4. 4. Milestones <ul><li>[See Hoff 01:7] </li></ul>
  5. 5. Normal language development L2 is increasingly difficult 15y + foreign accent in L2 11-14y grammatical refinement & expansion of vocabulary of L1/L2 3-10y acquisition of structure of L1/L2 21-36m from babbling to words in L1/L2 4-20m cooing 0-3m Language milestone Age
  6. 6. How lateralization develops <ul><li>Equipotentiality hypothesis (Lenneberg 1967) </li></ul><ul><ul><li>LH & RH have equal potential for language at birth </li></ul></ul><ul><li>Invariance hypothesis </li></ul><ul><ul><li>LH is specialized for language at birth </li></ul></ul>
  7. 7. Evidence from processing studies with children <ul><li>Molfese, Freeman & Palmero (1975) found that 10m showed same lateralization for speech vs. non-speech sounds as 4y-11y and adult </li></ul><ul><li>Dichotic listening shows right ear advantage for children as young as 2y </li></ul>
  8. 8. Evidence from childhood aphasia & brain injury prior to language <ul><li>Few children get aphasia </li></ul><ul><li>It invariably follows LH but not RH injury </li></ul><ul><li>Children get more non-fluent/Broca aphasia; adults get more fluent/Wernicke aphasia </li></ul><ul><li>Recovery is faster in children, see next slide </li></ul>
  9. 9. Effect of LH lesion at age aphasiac symptoms persist (usually irreversible if more than 3-5m) 15y + aphasiac symptoms no longer recovered from fully 11-14y aphasiac symptoms but with full recovery 3-10y L1 lost, reacquired with repetition of all stages 21-36m “ 4-20m 50% no effect, 50% delayed onset of language but normal development 0-3m Effect of LH lesion Age
  10. 10. Conclusions LH dominant in 97% population 15y + LH becomes dominant (invariance) 11-14y LH takes over more responsibility, but language can still be re-established in RH if LH is damaged 3-10y LH begins to assume responsibility 21-36m “ 4-20m no lateralization of language (equipotentiality) 0-3m Organization of hemispheres Age
  11. 11. Basic processes in neurological development <ul><li>Neural plasticity </li></ul><ul><ul><li>Children’s brains are more plastic than adults </li></ul></ul><ul><ul><li>The brain grows redundant connections among neurons from fetal development to 2y </li></ul></ul><ul><ul><li>Connections that are used are stabilized; most others are erased (pruned) </li></ul></ul><ul><li>Changes in functional asymmetry </li></ul><ul><ul><li>The child initially uses both hemispheres because the LH isn’t ready yet (LH > grammar), or </li></ul></ul><ul><ul><li>The child uses both hemispheres until the acquisition of grammar causes a shift to LH specialization (grammar > LH) </li></ul></ul>
  12. 12. The critical/sensitive period <ul><li>It appears that there is a period during which children must be exposed to language for language to develop at all </li></ul><ul><li>What experiment would you do to test this prediction? </li></ul><ul><ul><li>Wild/feral children </li></ul></ul><ul><ul><li>Genie </li></ul></ul><ul><ul><li>Late acquisition of sign language </li></ul></ul><ul><ul><li>L2, for & against </li></ul></ul>
  13. 13. The genetics of language development <ul><li>It is a maturational process, the course and timing of which is determined by the unfolding of a genetic blueprint. </li></ul><ul><li>Twin studies suggest that syntactic development is more controlled by genetics than vocabulary development. -- What does this mean in our terms? </li></ul><ul><li>Genetic language impairments, known as ‘specific language impairment’ or ‘developmental dysphasia’ </li></ul><ul><ul><li>see upcoming slides </li></ul></ul>
  14. 14. A story told by a 4.5y child with SLI <ul><li>The man got on the boat. He jump out the boat. He rocking the boat. He drop his thing. He drop his other thing. He tipping over. He fell off the boat. </li></ul><ul><li>Lindner & Johnston (1992), cited in Hoff (2001:354) </li></ul>
  15. 15. Sentences produced by a 16y with SLI <ul><li>Then he went home and tell mother - his mother - tell what he doing that day. </li></ul><ul><li>Then about noontime those guy went in and eat and warm up. </li></ul><ul><li>That boy climbing a rope to get to the top the rope. </li></ul><ul><li>He want play that violin. </li></ul><ul><li>Those men sleeping. </li></ul><ul><li>That man in a dark room. </li></ul><ul><li>Can I play with violin? </li></ul><ul><li>Weiner (1974), cited in Hoff (2001:355) </li></ul>
  16. 16. Specific language impairment/ Developmental dysphasia <ul><li>Cognition </li></ul><ul><ul><li>normal, as measured by IQ tests </li></ul></ul><ul><ul><li>slower at processing information </li></ul></ul><ul><li>Language </li></ul><ul><ul><li>Acquisition is delayed or deviant but with no obvious neurological cause </li></ul></ul><ul><ul><li>In English, this is seen in problems with inflectional morphology, but languages with richer morphologies (Italian, Hebrew) do not show this problem </li></ul></ul><ul><li>SLI runs in families: Gopnik found it in 16/30 members of a single family over 3 generations </li></ul><ul><li>Several analyses have been proposed </li></ul><ul><ul><li>some features of morphology are missing (number & tense) </li></ul></ul><ul><ul><li>inflectional morphology is not salient phonologically </li></ul></ul><ul><ul><li>difficulty processing stimuli presented rapidly </li></ul></ul>
  17. 17. Language and other species <ul><li>Primates </li></ul><ul><li>The birds & the bees </li></ul>
  18. 18. The origin of language <ul><li>Evolutionary psychology </li></ul><ul><li>Language is an adaptation </li></ul><ul><ul><li>Modularity: language is a mechanism specifically adapted for communication, i.e. a cognitive module [and a kind of mutation] </li></ul></ul><ul><ul><li>Non-modularity: language evolved gradually by adding new communicative functions to existing neural hardware; there is no neural mechanism dedicated exclusively to language </li></ul></ul>
  19. 19. Next time <ul><li>I am away next week; you will see two videos </li></ul><ul><li>Bellugi et al. &quot;Williams syndrome&quot; </li></ul><ul><li>Q5 on Tuesday Oct 24, on this week’s material </li></ul>

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