Dyslexia Dysgraphia ADHD 091112

44 Pages·2012·4.15 MB·English

by  Jing Yan

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