Introduction 2004 2002 1997 In WAIS III, the intelligence pattern is described at three levels: The first level contains Performance Intelligence and Verbal Intelligence. The second level consists of the four factor scales: Verbal Comprehension, Perceptual Organization, Freedom from Distractibility and Processing Speed. The third level contains the subtests. The following paragraphs summarizes research on the intelligence profiles of adults with the autistic disorder or Asperger syndrome on the basis of these three levels. 2001 1992 1996 2002 2000 2001 2000 2001 No studies have been performed on WAIS-III profiles for adults with HFA or Asperger syndrome as far as we know. Therefore no information is available on the results of factor scales in these groups. This leads to the conclusion that the most important factors of the intelligence pattern for adults with HFA or Asperger syndrome are still unknown. 2001 1988 1996 In summary, research shows that among adults with HFA or Asperger syndrome, results of VIQ-PIQ differences vary and may be influenced by the validity problems of the VIQ-PIQ dichotomy. The factor scale scores and the subtest patterns provide a better representation of the intelligence pattern. Aims of the Present Study The present study aims to acquire insight into the WAIS III profiles of normal intelligent adults with HFA and Asperger syndrome. Profiles in the total group and differences between the two diagnostic groups will be examined. Methods Procedure All participants were recruited from the GGZ (Mental Health Center) Eindhoven and Oost-Brabant. The participants met the criteria for Asperger syndrome or HFA. Participants with relevant neurodevelopmental conditions and genetic conditions were excluded, as were institutionalized patients and patients with a Full Scale IQ below 80. Subjects  1 Table 1 Characteristics of participants IQ and age M SD Range     Full scale IQ 110.16 16.05 83–145     Mean age 41.93 10.67 20–60 Diagnosis n %      Autistic disorder 16 37.2       Asperger syndrome 27 62.8   Gender     Male 39 90.7       Female 4 9.3   Education     Lower/middle education 18 41.9       Higher education 25 58.1   Employment status     Employed or retired 30 69.8       Studying 1 2.3      Unemployed 12 27.9   Current living circumstances     Lives with partner 23 53.5       Lives independently  12 27.8       Sheltered living 2 4.7       Lives with parents  6 14.0   All individuals ranged in age from 18 to 60 years. The mean age was 41.93. Of all participants, 25 finished higher education and 30 individuals had work. 23 participants lived together with a partner. The relatively large number of participants who had a relationship, worked and were well educated emphasizes the relatively high level of functioning in this group. Assessment of Disorder  1994 1994 1992 2001 1989 1993 Assessment of Intelligence  1997 1999 1997 Results Analyses were done at the three WAIS-III levels: VIQ versus PIQ, the four factor scales and all subtests. Preliminary analysis included checks for normality, linearity, influential data points and assumptions of repeated measures. No serious deviations were found. T-tests showed that both diagnosis groups were comparable in education and work status, as well as in gender distribution. Differences Between WAIS III VIQ and PIQ t- 2 Table 2 VIQ and PIQ differences in the total group and in diagnostic groups  VIQ PIQ  n M SD M SD Total group 110.30 13.83 108.42 18.21 1.88 43 Asperger 111.41  13.57 112.52 17.28 1.11 27 Autistic disorder 108.44 14.49 101.50  18.13 6.94 16 Differences Between Factor Scale Scores F p < F p p p p p p 3 Table 3 Factor scale scores for the total group and the diagnostic groups Factor scale M SD N Verbal comprehension Autistic disorder 107.5* 12.1 16 Asperger syndrome 110.8 11.9 27 Total 109.6* 12.0 43 Perceptual organization Autistic disorder 105.0* 18.7 16 Asperger syndrome 111.8 13.0 27 Total 109.3* 15.5 43 Freedom from distractibility Autistic disorder 105.1* 18.2 16 Asperger syndrome 107.2 15.4 27 Total 106.4 16.3 43 Processing speed Autistic disorder 91.8* 17.4 16 Asperger syndrome 106.5 19.4 27 Total 101.0* 19.8 43 p Differences Between WAIS III Subtest Scores 4 F p < Table 4 Mean standardized subtest scores for the total group Subtest scores  M SD n Vocabulary 11.63* 2.564 43 Similarities 11.42 2.490 43 Arithmetic 11.77* 3.046 43 Digit span 10.72 3.268 43 Information 12.42* 2.779 43 Comprehension 12.53* 2.772 43 Letter-number sequencing 10.98 2.956 43 Picture completion 10.88 3.253 43 Digit-Symbol Coding 9.81* 3.438 43 Block design 12.02* 3.562 43 Matrix reasoning 11.98* 2.454 43 Picture arrangement 11.53 3.731 43 Symbol search 10.37* 3.970 43 Object assembly 11.16 3.086 43 p F p 5 6 Table 5 Mean standardized subtest scores for the autistic disorder group Subtest Scores  M SD N Vocabulary 11.31 2.496 16 Similarities 10.94 1.769 16 Arithmetic 11.44 3.705 16 Digit span 11.31 3.400 16 Information 12.13* 3.284 16 Comprehension 11.75 2.176 16 Letter-number sequencing 10.25 3.152 16 Picture completion 10.81 4.070 16 Digit-Symbol Coding 8.38* 3.030 16 Block design 10.56 3.444 16 Matrix reasoning 11.44* 2.828 16 Picture arrangement 10.19 3.674 16 Symbol search 8.44* 3.483 16 Object assembly 9.88 3.324 16 p Table 6 Mean standardized subtest scores for the Asperger syndrome group Subtest scores M SD n Vocabulary 11.81 2.632 27 Similarities 11.70 2.826 27 Arithmetic 11.96 2.638 27 Digit Span 10.37* 3.200 27 Information 12.59 2.485 27 Comprehension 13.00* 3.013 27 Letter-number sequencing 11.41 2.805 27 Picture completion 10.93 2.745 27 Digit-Symbol Coding 10.67 3.431 27 Block design 12.89* 3.401 27 Matrix reasoning 12.30 2.198 27 Picture arrangement 12.33 3.595 27 Symbol search 11.52 3.847 27 Object assembly 11.93 2.716 27 p p p p p p p p p p p p p p Discussion WAIS VIQ Versus PIQ 2000 2001 WAIS III Factor Scale Level 1997 2005 1993 WAIS III Subtest Level Analyses showed different Subtest patterns in the HFA and the Asperger syndrome groups. The HFA group performed significantly low in Digit-Symbol Coding and Symbol Search. These two subtests together form the Processing Speed Factor. The low scores for these subtests represent the problems in speed of processing visual information as described in the preceding paragraph. 1999 1995 2005 1997 1997 2005 1992 2005 2005 2003 1996 1999 2005 1993 1993 Conclusions The present study found people with Asperger syndrome to differ significantly from people with HFA in WAIS III Factor Scale profiles and WAIS III Subtest patterning. In people with HFA Processing Speed problems were found. Further, the HFA and Asperger syndrome group showed different subtest patterns. The present study supports the idea that HFA and Asperger syndrome can be differentiated empirically at the level of intellectual functioning. This lends support to the hypothesis that HFA and the Asperger syndrome are two separate disorders.