DYSLEXIA,  DYSGRAPHIA,   AND  ADHD   Carol  Wilkinson,  Jessica  Witkowski,  and  Jenna  Klotz   Development  and  Behavioral  Pediatrics     September  11,  2012 Dyslexia   DefiniNon   ¨  Characterized  by  difficulNes  with  accurate  word   ¤  recogniNon,  poor  spelling  and  decoding  abiliNes   Must  not  be  due  to  inadequate  instrucNon   n  Must  occur  in  context  of  normal  cogniNve  funcNoning   n  A  neurobiological  condiNon   ¨ Background   Most  common  learning  disability   ¨  Boys  >  girls   ¤  Risk  factors   ¨  Family  history   ¤  History  of  SLI   ¤  Environmental:  low  exposure  to  books  and  instrucNon   ¤  in  pre-­‐reading  skills,  poverty,  low  parental  educaNon. • Recognizes  leZers  and  words   • Form  assoc.  with  leZers  that  co-­‐occur   • Allows  for  recogniNon  of  words  that   don’t  follow  typical  leZer-­‐sound   correspondence  (i.e.  yacht)       • Facilitates   • Understanding  of  text   understanding  of   being  read   meaning  of  words  as   • Uses  syntax,  semanNc,   they  are  read   and  pragmaNc   knowledge   • Forms  associaNons  of  words/syllables  with  sounds  (phonemes)   • Back  up  the  larger  system  (used  to  “sound  out”  an  unknown  word) Phonological  deficit  hypothesis   Lack  of  phonemic  awareness  blocks  access  to  higher   ¨  order  process  involved  in  comprehension.   Several  studies  have  shown  children  with  dyslexia  are   ¤  impaired  in  phonological  processing  tasks   n  Example:  Children  with  dyslexia  and  normal  readers  were   compared  with  reading  one  and  two-­‐syllable  nonwords   n  Dyslexics  made  more  errors  in  reading  nonwords  aloud,  especially   with  phonological  complexity  (p  <  0.05) Neurobiology   DisrupNon  of  led  hemisphere  posterior  brain  systems   ¨  Study  of  24  dyslexic  children  and  15  normal  reading   ¨  children   Asked  to  press  a  buZon  when  2  visually  presented  leZers   ¤  rhymed  (ie  D  and  T)  and  then  when  2  leZers  were  the  same   (D  and  D)   n  By  comparing,  can  determine  which  brain  acNvity  was  due  to   phonological  demands  (rhyme  task)  vs.  orthographic  (same   leZers)   Asked  to  press  a  buZon  when  2  leZers  matched  and  then   ¤  when  2  lines  had  the  same  orientaNon  (ie  I  and  I)     n  To  determine  brain  acNvity  due  to  orthographic  processing Behavioral  Results   Dyslexic  children  were  less  accurate  for  rhyme   ¨  leZers  (p  =  0.05)   No  difference  between  groups  for  match  leZers  or   ¨  match  lines  (p  >  0.1)   Performance  on  rhyme  task  correlated  with   ¨  reading  for  all  subjects  (p  =  0.005) Rhyme  vs.  LeZer  Matching   Both  groups  showed   ¨  acNvaNon  of  led  frontal  lobe   with  leZer  match   Normal  reading  children   ¨  show  led  temporo-­‐parietal   regions  with  rhyming   Dyslexic  children  showed  no   ¨  acNvaNon  of  led  temporo-­‐ parietal  cortex  with  rhyming   Led  temporo-­‐parietal  region   ¨  not  acNvated  in  leZer  match   task   ¤  Deficit  is  phonological