Developmental Disabilities

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Developmental Disabilities

• Autistic Spectrum Disorder
• 1 in 200 (and increasing)
• Attention Deficit and Hyperactivity Disorder
• Dyslexia

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Autistic Spectrum Disorder

• Three essential types, based on severity of
  developmental impairment
• Autistic Disorder (Autism) - 2 in 1000
• PDD-NOS (Pervasive Developmental Disorder - Not
  Otherwise Specified) - 1.5 in 1000
• Aspergers Disorder - 0.5 in 1000
• Can be diagnosed as early as 2 but not usually
  until enter school or by chance are seen by a
  professional

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Autistic Symptoms

• Deficits in Social Interaction
• May prefer to be alone
• May prefer adults
• No eye contact or use peripheral vision
• No response or understanding of facial gestures
• Touching feels painful or upsetting (withdraw
  from physical contact)

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Autistic Symptoms

• Deficits in Verbal and Non-Verbal Communication
• Speech and language skills may begin to develop
  and then be lost, or they may develop very slowly
  or they may never develop
• Without early intervention, more than 40 of
  children do not talk at all
• Some communicate with gestures instead of words
• Difficult to imitate sounds and words
• Others have echolalia, which is repeating
  something heard
• Words may also be used without their usual
  meanings
• Confusing gender and/or pronouns

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Autistic Symptoms

• Deficits in Verbal and Non-Verbal Communication
  (cont.)
• Voices sound flat and cannot control how loudly
  or softly they talk
• Hard to initiate communication and to keep a
  conversation going
• Stand too close to the people they are talking to
• Some speak well and have a wide vocabulary, but
  have a hard time listening
• They go on at length, rather than have a
  back-and-forth discussion.

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Autistic Symptoms

• Repetitive behaviours and routines
• Have ritualistic actions that they repeat
• spinning, rocking, staring, finger flapping,
  hitting self
• Take unusual risks with no fear of real dangers
• Unusual postures, walking or movement patterns
• Depend on routines and things staying the same so
  there are no surprises
• Small changes in environment or daily routines
  might trigger acute distress or fear
• Have a restricted pattern of interests and odd
  habit
• talk about or focus obsessively on only one
  thing, idea, activity or person

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Autistic Symptoms

• Responses to Sensations
• Have auditory and visual processing problems
• sensory input may be scrambled and/or
  overwhelming
• Heightened sensitivities to sounds, sights,
  touch, taste and smells
• high-pitched intermittent sounds may be painful
• rough or scratchy fabrics may be intolerable
• Have either very high pain thresholds (i.e.
  insensitive to pain) or very low pain thresholds

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Autistic Symptoms

• Effects on Learning
• Many of the previous aspects of ASD listed above
  can interfere with the ability to learn through
  typical teaching methods
• Lack of spontaneous or imaginative play
• An inability to imitate other
• Inability to focus on the task at hand -- very
  short attention span
• Difficulty sharing attention with others (joint
  attention)
• Difficulty with abstract ideas and representation
• Difficulty grasping the concept of time

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Autistic Symptoms

• Typically, in order to diagnose autism, 3 classes
  of the above behaviors are needed
• Social relationship difficulties
• Impairment of verbal and nonverbal communications
• Repetitive behaviors
• However, there are also perceptual and
  attentional deficits
• which may underly autistic deficits in general

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Attention and Autism

• Research has found that autistics are superior at
  performing a conjunctive visual search (Plaisted
  et al., 1998)
• Tested with a feature search (red S among red T
  and green X distractors) and a conjunction search
  (red X among red T and green X distractors)
• Normals showed an increasing search time on
  conjunction search as the number of distractors
  increased
• Autistics were faster and search time increased
  less on conjunction search

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Attention and Autism

• ORiordan et al (2001) matched normals and
  autistics for general ability (IQ)

In Experiment 1, found that feature search was
essentially identical for normals and
autistics. But, autistics were better than
normals on conjunction search.
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Attention and Autism

• ORiordan et al (2001) also tested for improved
  performance on more difficult feature searches
• Tilted line among vertical lines vs. vertical
  among tilted

In Experiment 2, found that easy search was
essentially identical for normals and
autistics. But, autistics were better than
normals on hard search.
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Attention and Autism

• ORiordan et al (2001) results
• challenge view of autistics having difficulty
  with perceptual integration
• seem inconsistent with view that autistics have
  impaired shifting of attention
• there are different types of shifting so that
  used in visual search (exogenous) and the one
  impaired (endogenous)might not be the same

14
Attention and Autism

• Superior search by autistics
• due to better perceptual discrimination
• stronger inhibitory and excitatory mechanisms
• predicts greater effects on negative priming
• perhaps have superior inhibition of return

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Attention and Autism

• Autistics have unusual gaze or looking behavior
• For example, when presented with 2 stimuli, make
  few back and forth shifts of attention
• Have been categorized as having tunnel vision
• particularly, poor discrimination as perceptual
  features get further apart
• Atypical eye gaze seen as underlying
  social-communicative impairment
• Deficits in visual orienting/attentional
  disengagement may underly emotional regulation,
  social-communicative, and temperamental style
  impairments

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Attention and Autism

• Visual orienting is classically measured by
  visual cueing task
• RTs are faster on valid than invalid trials
• This difference is more pronounced for autistics,
  perhaps due to greater difficulty in disengaging
  on invalid trials
• This ability is presumably related to processing
  in the posterior parietal cortex -- an area shown
  to have abnormalities in autistics who have
  difficulty disengaging
• Are disengagement deficits specific to autism
• Is deficit due to disengagement or shifting

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Attention and Autism

• Landry Bryson (2004) attempt to answer
  questions by using a simplified cueing task
• 3 computer screens
• stimulus first presented on center screen then on
  a side screen
• manipulation is whether center stimulus remains
  on (disengagement) or off (shifting) when side
  stimulus is presented
• compared to normals and Down

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Attention and Autism

• Autistics took longer to orient than normals or
  Down
• Autistics and normals took longer to orient on
  disengage than shift trials
• Autistics took longer to disengage than other
  groups
• 18 of autistics did not complete during time
  limit compared to 7.7 and .8 for normals and
  Down

19
Attention and Autism

• Autistics have difficulty disengaging
• 3- to 7-yr-old autistics were similar to
  2-month-olds in apparently showing obligatory
  attention
• There was no relation between deficits in
  disengaging and intelligence level
• Thus, attention in autistics is overly focused
  and uses a narrow beam
• This dysfunction may be a general aspect and
  underly behavior to social as well as non-social
  stimuli

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Attention Deficit Hyperactivity Disorder

• Characteristics
• Inability to regulate activity level
• Difficulty inhibiting behavior (impulsivity)
• Difficulty attending to task at hand (focused
  attention)
• First detectable in preschool years, and persists
  into adolescence and adulthood

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ADHD

• Affects 5 of school-age children, 4 of adults
• 3 times more common in boys than girls

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ADHD Symptoms

• Hyperactivity
• constant movement
• not sitting still
• moving around when others are seated
• talking excessively

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ADHD Symptoms

• Impulsivity
• acting without thinking
• starting new task before completing previous
• Inattention
• daydreaming
• distracted by other things
• makes careless mistakes
• loses track of personal items
• difficulty starting and organizing tasks

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Attention and ADHD

• ADHD show deficits in inhibiting responses to
  irrelevant stimuli
• Perform well on recall of spatial locations
• Differences in ERPs for ADHD and normals on
  attention task
• Deficits on Stroop-task

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Attention and ADHD

• Previous studies lumped different ages together
  in a single group
• Considering that there are developmental
  differences in selective attention, lumping may
  mask deficits and severity
• Brodeur and Pond (2001)
• narrow the age range and look for age differences
• whether or not methylphenidate has effect on ADHD
  performance on selective attention task
• how the nature of distracting stimuli (meaningful
  vs irrelevant) affects performance

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Attention and ADHD

• Used Flanker Task
• target (pictures of shirt or tie) alone, flanked
  by either meaningful or irrelevant visual
  distractors, with either a meaningful or
  irrelevant auditory distractor, or either with
  both meaningful or auditory visual and auditory
  distractors

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Attention and ADHD
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Attention and ADHD

• ADHD were effected more by distractors
• For both ADHD and normals, younger were affected
  more by distractor modality
• Visual and VisualAuditory were more distracting
• Distractor meaning only affected normals
• Effects not related to medication
• except that on-MPH were faster overall

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Attention and ADHD

• Poor performance may be due to
• general perceptual inefficiency
• poor motor control
• sensitive to interference from previous trials
• Age effects
• may be related to an increase in attentional
  capacity
• increase in inhibitory mechanisms
• Medication effects
• may improve ability to stay on task but not
  ability to process information

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Attentional Deficiencies

• Both Autism and ADHD seem to suffer from
  attentional deficiencies
• In particular, inhibitory mechanisms may be at
  fault
• Considering that both are usually not diagnosed
  until preschool or grade school, detection of
  early attentional deficits could have a huge
  impact