1. Rationale and Hypotheses
Intellectual & Academic Profiles of Children with Asperger’s Disorder or Nonverbal Learning Disability
Marcia N. Gragg, Joseph E. Casey1, Christine M. Drummond & Adam D. Kayfitz University of Windsor & 1Ozad Institute
Intellectual & Academic Profiles: AD & NLD
Results
AD & NLD groups did not differ significantly in verbal abilities
NLD group had VIQ significantly higher than PIQ, no VIQ/PIQ difference was found for the AD group
AD group had significantly higher visual-perceptual abilities than did the NLD group
only 1/11 of the AD group, and 14/25 of the NLD group had VIQ/PIQ split greater than 15 points
AD group had significantly higher performance on tasks involving identifying missing parts in pictures, assembling blocks to match geometric designs, and assembling puzzles
two groups did not differ significantly on any other intellectual tasks, including arithmetic tasks
no significant differences between the 2 groups in academic achievement, including reading, spelling & mathematics
both groups showed better reading & spelling than arithmetic, significantly higher for the NLD group only
Introduction
some researchers suggest that most children with Asperger’s Disorder (AD) have the same cognitive profile as Nonverbal Learning Disabilities (NLD) (Gunter et al, 2002; Rourke et al, 2002)
children with NLD, by definition, have better developed verbal than visual-perceptual abilities i.e. higher Verbal Intelligence Quotient than Performance IQ (VIQ/PIQ split)
others suggest that the cognitive profiles of AD and NLD are distinct i.e. children with AS do not necessarily have better verbal than visual perceptual abilities (e.g. Barnhill et al, 2000)
there may be partial overlap in the cognitive profiles of some children with AS and NLD (Gillberg, 2004)
Rationale and Hypotheses
to compare the cognitive & academic profiles of children with AD and NLD
we expected that a minority of children with AD would show a NLD cognitive profile AD
NLD
Conclusions
the AD group in our sample demonstrated a different intellectual profile to the NLD group
future research needs to compare behavioural characteristics of AS and NLD
Diagnostic Comparison
Method
Participants
Consecutive cases of children referred to a neurodevelopment clinic who met criteria for AD (n = 11 males, mean age = 8.3) or NLD (n = 25, 18 males, 7 females, mean age = 9.7)
WISC-III FSIQ between 67 and 120
Materials
Weschler Intelligence Test for Children, 3rd Edition (WISC-III)
Weschler Individual Achievement Test(WIAT)
Characteristics
Autism
Asperger’s
NLD
Type of Diagnosis
DSM IV, behavioural
ability-related
Who Diagnoses?
Psychologist, Physician
Neuropsychologist
Diagnostic Tests
behaviour, early history
ability, achievement, motor
Required Criteria for Diagnosis
social, communication, behaviour
VIQ/PIQ split, tactile perceptual & psychomotor deficits
Social
qualitative impairment in social interaction (nonverbal, peers, sharing, reciprocity)
not required for diagnosis
Language
qualitative impairments in communication (delay in language, impaired conversation, stereotyped speech, play)
no clinically significant delay in language (single words by 2 years, phrases by 3 years)
higher language than visual-perceptual abilities
Behaviour
restricted, repetitive, & stereotyped patterns of behavior, interests, & activities (interest, rituals, mannerisms, preoccupations)
restricted, repetitive, stereotyped behavior, interests, & activities (interest, rituals, mannerisms, preoccupations)
Cognition
no clinically significant delay in cognitive, self-help skills, adaptive behavior, & curiosity about the environment
Verbal IQ significantly higher than Performance IQ, tactile perceptual deficit
Motor
psychomotor deficits
Age at Onset
before 3 years of age
Gender Ratio
4.3 boys:1 girl
5.7 boys:1 girl
Typical Age at Diagnosis
3 ½ years
6 years
See HFA/Asperger’s/NLD study at;
more females than other disorders
9 years