Predictors and correlates of adaptive functioning in children with developmental disorders

Brief report: the Vineland Adaptive Behavior Scales in young children with autism spectrum disorders at different cognitive levels

Vineland Adaptive Behavior Scales (VABS) data were examined in a large sample of young children with ASD (n = 290) of varying cognitive levels. IQ was higher than VABS composite score among high functioning children only; the opposite pattern was found in lower IQ subgroups. Profile analysis of VABS domains across cognitive levels demonstrated different profiles in different subgroups. A characteristic "autism profile" was found for most subgroups for Age Equivalents but not Standard Scores. In a small set of matched pairs (n = 28) of children with autism versus MR, significantly different profiles were found, with Socialization and Communication lower in autism, but no differences were found between matched pairs of children with autism and PDD-NOS (n = 48). Correlations between age, cognitive level, and adaptive level were also reported, and regression analyses indicated that autism severity accounts for a modest amount of unique variance in Socialization and Daily Living Skills.

Evidence for latent classes of IQ in young children with autism spectrum disorder

Autism is currently viewed as a spectrum condition that includes strikingly different severity levels; IQ is consistently described as one of the primary aspects of the heterogeneity in autism. To investigate the possibility of more than one distinct subtype of autism based on IQ both latent class analysis and taxometrics methods were used to classify Mullen IQs in a sample of 456 children with autism spectrum disorder. We found evidence for multiple IQbased subgroups using both methods. Groups differed in level of intellectual functioning and patterns of verbal versus nonverbal ability. Results support the notion of distinct subtypes of autism that differ in severity of intellectual ability, patterns of cognitive strengths and weaknesses, and severity of autism symptoms.

Autistic symptomatology and language ability in autism spectrum disorder and specific language impairment

BACKGROUND

Autism spectrum disorders (ASD) and specific language impairment (SLI) are common developmental disorders characterised by deficits in language and communication. The nature of the relationship between them continues to be a matter of debate. This study investigates whether the co-occurrence of ASD and language impairment is associated with differences in severity or pattern of autistic symptomatology or language profile.

METHODS

Participants (N = 97) were drawn from a total population cohort of 56,946 screened as part of study to ascertain the prevalence of ASD, aged 9 to 14 years. All children received an ICD-10 clinical diagnosis of ASD or No ASD. Children with nonverbal IQ > or =80 were divided into those with a language impairment (language score of 77 or less) and those without, creating three groups: children with ASD and a language impairment (ALI; N = 41), those with ASD and but no language impairment (ANL; N = 31) and those with language impairment but no ASD (SLI; N = 25).

RESULTS

Children with ALI did not show more current autistic symptoms than those with ANL. Children with SLI were well below the threshold for ASD. Their social adaptation was higher than the ASD groups, but still nearly 2 SD below average. In ALI the combination of ASD and language impairment was associated with weaker functional communication and more severe receptive language difficulties than those found in SLI. Receptive and expressive language were equally impaired in ALI, whereas in SLI receptive language was stronger than expressive.

CONCLUSIONS

Co-occurrence of ASD and language impairment is not associated with increased current autistic symptomatology but appears to be associated with greater impairment in receptive language and functional communication.

Variability in adaptive behavior in autism: evidence for the importance of family history

Adaptive behavior in autism is highly variable and strongly related to prognosis. This study explored family history as a potential source of variability in adaptive behavior in autism. Participants included 77 individuals (mean age = 18) with average or better intellectual ability and autism. Parents completed the Family History Interview about the presence of broader autism phenotype symptoms and major psychiatric disorders in first degree relatives. Adaptive behavior was assessed via the Vineland Adaptive Behavior Scales (VABS). Based on family history variables, age, and intelligence quotient (IQ), 87% of participants were correctly classified as having impaired or average VABS scores. Family history of depression and shyness accounted for the most variance in VABS scores, and they had the greatest influence on VABS Socialization scores in particular. Possible underlying mechanisms include genetics, psychosocial factors, and social resources. This study provides initial evidence of the importance of family history to adaptive behavior in autism and has implications for genetics and treatment.

Pragmatic Assessment in Autism Spectrum Disorders: A Comparison of a Standard Measure With Parent Report

The purpose of this study was to investigate the concurrent validity of subtests on the Comprehensive Assessment of Spoken Language (CASL) by comparing them with the assessment of communication and social skills on the Vineland Adaptive Behavior Scales (Vineland). The participants were 35 children and adolescents with higher functioning autism spectrum disorders (ASD) who had received both the CASL and the Vineland. Results of the study suggest that the Pragmatic Judgment and Inferences subtests of the CASL appeared to document the difficulties that individuals with ASD had in adaptive use of language for communication.

Neuropsychological predictors of everyday functioning in adults with intellectual disabilities

BACKGROUND

Very little is known about the neuropsychological correlates of adaptive functioning in people with intellectual disabilities (ID). This study examined whether specific cognitive deficits and demographic variables predicted everyday functioning in adults with ID.

METHOD

People with ID (n = 101; ages 19-41 years; mean education = 11 years; 34% women; 54% competitively employed; 41% with mild ID) completed a comprehensive neuropsychological battery grouped into four cognitive domains: processing speed, verbal memory and comprehension, visual perception/constructive function, and executive function. In addition, parents completed an 89-item rating scale developed to assess a wide range of independent living skills.

RESULTS

Confirmatory factor analysis results confirmed a correlated four-factor model of cognitive function and a unidimensional model of everyday functioning. Furthermore, structural equation modelling results supported the predictive relationship of verbal memory/comprehension and employment status (standardized regression coefficients 0.45, 0.22, P < or = 0.01 for each) to measures of everyday functioning. The two variables together explained 35% of the variance in everyday functioning.

CONCLUSIONS

Both general cognitive dysfunction and specific verbal memory and comprehension deficit impair daily functions in people with ID. These findings have implications for predictive models of adaptive functioning, and for cognitive rehabilitation and deficit compensation strategies for this group.

Children with autism: quality of life and parental concerns

Past research has shown that children with autism and their families have compromised quality of life (QOL) in several domains. This study examined QOL and parental concerns in children with autism during early childhood, childhood, and adolescence compared to children with Attention Deficit Disorder/Attention Deficit Hyperactivity Disorder (ADD/ADHD) and to typical controls from a US national sample. Families with children diagnosed with autism reported more profound QOL effects than families of children with ADD/ADHD or unaffected controls. Children with autism were significantly less likely to attend religious services, more likely to miss school, and less likely to participate in organized activities. Parental concerns over learning difficulty, being bullied, stress-coping, and achievement were overwhelming in the autism group relative to the comparison groups.

What happens to children with PDD when they grow up? Prospective follow-up of 219 children from preschool age to mid-childhood

OBJECTIVE

To describe the psychological development of children with pervasive developmental disorders over a period of 3 years and to identify the factors linked to their developmental paths.

METHOD

The study was a collaborative and prospective follow-up study of 219 preschoolers. Retrospective data and enrollment data were collected at the beginning of the study and 3 years later.

RESULTS

We observed high variability in the short-term outcomes of preschoolers. In line with previous research, our results showed that intellectual, linguistic and adaptive functioning were useful for predicting outcome. The severity of a child's autistic symptoms appears to be related to his or her future development. These variables can therefore be used as predictors of outcome for preschoolers with autism.

CONCLUSION

Developmental and symptom changes in young children with autism should not be overlooked and need to be assessed regularly in view of choosing suitable servicing programs.

A neuropsychological assessment of frontal cognitive functions in Prader-Willi syndrome

BACKGROUND

Prader-Willi syndrome (PWS) is associated with a characteristic behavioural phenotype whose main features are, alongside compulsive hyperphagia, deficits in social behaviour: social withdrawal, temper tantrums, perseverative speech and behaviour, mental rigidity, stereotyped behaviour, impulsiveness, etc. Similar symptoms may also be found in autistic spectrum disorders and lesional pathologies of the frontal lobe. In both cases, such symptoms have been related to dysfunctions in frontal cognitive processes such as attention, working memory and executive functions. This study uses standardized neuropsychological instruments to analyse the degree to which these processes are affected in PWS.

METHODS

The sample comprised 16 individuals with a genetically confirmed PWS diagnosis. Subjects' IQ (Wechsler Adult Intelligence Scale), academic level, laterality and body mass index (BMI) were calculated. Attention, memory and executive functions were analysed using standard, widely employed neuropsychological tests. We compared the results of the sample group with the general population. Correlation analyses were carried out with IQ, academic level and BMI.

RESULTS

In all the neuropsychological measures focusing on attention, executive functions and visuoperceptual organization, the study sample scored significantly lower than the normative reference population. The scores of the tests used for measuring immediate memory were also significantly lower when trials required sequential processing, although not when they required simultaneous processing. In the memorization of a list of words, subjects showed an initial deficit which disappeared with repetition, enabling them to obtain scores similar to the reference population. No significant correlations were found with BMI, and a higher IQ or academic level did not improve scores in the majority of tests.

CONCLUSIONS

The study shows a deficit in elementary frontal cognitive processes in PWS patients. This deficit may be involved in the social behaviour disorders that characterize such patients, as described in other development or frontal syndrome pathologies. However, we cannot affirm that the deficits found are specific to PWS; they could also occur in other causes of intellectual disability. Although in the study sample IQ did not correlate with frontal deficits, further research is needed to establish whether the neuropsychological alterations described form part of a cognitive phenotype for PWS. We believe that our understanding of the social behaviours typical of PWS may be improved by taking into consideration the cognitive functioning models of the prefrontal lobe, particularly those applied to pervasive developmental disorders.

Social and Communication Abilities and Disabilities in Higher Functioning Individuals with Autism Spectrum Disorders: The Vineland and the ADOS

The relationship between adaptive functioning (ability) and autism symptomatology (disability) remains unclear, especially for higher functioning individuals with autism spectrum disorder (ASD). This study investigates ability and disability using the Vineland and Autism Diagnostic Observation Schedule (ADOS), respectively, in two clinical samples of children with ASD. Participants included 187 males with VIQ > 70. Vineland scores were substantially below VIQ, highlighting the magnitude of adaptive impairments despite cognitive potential. A weak relationship was found between ability and disability. Negative relationships were found between age and Vineland scores and no relationships were found between age and ADOS scores. Positive relationships were found between IQ and Vineland Communication. Results stress the need for longitudinal studies on ability and disability in ASD and emphasize the importance of adaptive skills intervention.

Adaptive and maladaptive behavior in children with Smith-Magenis Syndrome

Children with Smith-Magenis Syndrome (SMS) exhibit deficits in adaptive behavior but systematic studies using objective measures are lacking. This descriptive study assessed adaptive functioning in 19 children with SMS using the Vineland Adaptive Behavior Scales (VABS). Maladaptive behavior was examined through parent questionnaires and the Childhood Autism Rating Scale. Cognitive functioning was evaluated with an age-appropriate test. Children scored below average on VABS Communication, Daily Living Skills, and Socialization scales. Learning problems and hyperactivity scales on the Conner's Parent Rating Scale were elevated, and girls were more impulsive than boys. Stereotypic and self-injurious behaviors were present in all children. Cognitive functioning was delayed and consistent with communication and daily living skills, while socialization scores were higher than IQ.

Improving the reliability of autism diagnoses: examining the utility of adaptive behavior

The classification agreement of the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS) was examined in 129 children and adolescents (aged 7-18 years) who were evaluated for autism. Participants received a diagnosis of autism or non-autism based on the ADI-R. Linear discriminant analysis revealed adequate concordance between the ADI-R and ADOS, with 75% of the participants being correctly classified using the ADOS. Classification accuracy significantly improved to 84% when a measure of adaptive functioning (i.e., the Vineland Adaptive Behavior Scales) was included in the analysis. The findings suggest that when clinicians obtain discrepant information on the ADI-R and ADOS, assessment of an individual's adaptive functioning may reduce diagnostic errors.

[Quality of life and autism]

OBJECTIVE

To evaluate the index quality of life (QL) in bearers of including upset of the development.

METHOD

20 autistic children, between 4 and 12 years, submitted to the diagnostic evaluation by autistic traces scale-ATA and for the Vineland adaptive behavior scales, needing to obtain in this a quotient of superior development over 70. The data about QL were obtained by the scale of quality of life-AUQEI and compared from the application of Vineland and of AUQEI in a population of normal children, resembling in the sex and in the age.

RESULTS

In the evaluation of the ATA, average was 33.75 with 4.95 standard deviation. The indexes of Vineland suggest that normal children have larger probability to present level of appropriated adaptative behavior than autistic children (p=0.0196). Concerning QL, the general indexes are the same for both groups, indicating positive QL (p=0.744). In the sub domain autonomy, autistic children present higher index (p=0.0048).

CONCLUSION

Autistic children present similar indexes of QL than normal children.

Are abilities abnormally interdependent in children with autism?

We propose that stronger than usual correlations between abilities indicate which cognitive processes are impaired in autism. Study 1 compared partial correlations (controlling age) between intelligence and social cognition in children with autism (n = 18), mental retardation (MR; n = 34), or no psychological disorder (n = 37). Correlations were stronger in the autism group. Study 2 compared correlations between measures of perceptual organization and verbal comprehension, receptive and expressive language, fine and gross motor coordination, and theory of mind, emotion recognition, and emotion understanding abilities in children with autism (n = 30) or MR (n = 24) and in a large representative sample of children (n = 449). Results indicate that autism is marked by stronger correlations between all ability domains, and MR is marked by stronger correlations between motor coordination tasks and other ability measures.

Prelinguistic predictors of vocabulary in young children with autism spectrum disorders

PURPOSE

The goal of the current study was to identify a predictive model of vocabulary comprehension and production in a group of young children with autism spectrum disorders. Four prelinguistic behaviors were selected for consideration as predictors based on theoretical and empirical support for the relationship of these behaviors to language development.

METHOD

The study used a longitudinal correlational design. Participants were twenty-nine 2- and 3-year-olds diagnosed with autism spectrum disorders. The prelinguistic behaviors-attention-following, motor imitation, commenting, and requesting-were measured at the initial visit. Vocabulary comprehension and production were measured 6 months later.

RESULTS

Commenting was the only unique predictor of comprehension after the degree of cognitive delay was controlled. Both commenting and motor imitation of actions without objects were unique predictors of production over and above the other skills and when the degree of cognitive delay was controlled.

CONCLUSIONS

The finding that both commenting and motor imitation simultaneously accounted for unique variance in vocabulary production is new to the literature and requires replication. However, results suggest that increasing behaviors that allow children with autism to make their current focus of attention obvious to social partners may be an effective approach for supporting word learning in young children with autism.

Adaptive functioning and behaviour problems in relation to level of education in children and adolescents with intellectual disability

BACKGROUND

The interrelationship between adaptive functioning, behaviour problems and level of special education was studied in 186 children with IQs ranging from 61 to 70. The objective was to increase the insight into the contribution of adaptive functioning and general and autistic behaviour problems to the level of education in children with intellectual disability (ID).

METHODS

Children from two levels of special education in the Netherlands were compared with respect to adaptive functioning [Vineland Adaptive Behavior Scales (VABS)], general behaviour problems [Child Behavior Checklist (CBCL)] and autistic behaviour problems [Autism Behavior Checklist (ABC)]. The effect of behaviour problems on adaptive functioning, and the causal relationships between behaviour problems, adaptive functioning and level of education were investigated.

RESULTS

Children in schools for mild learning problems had higher VABS scores, and lower CBCL and ABC scores. The ABC had a significant effect on the total age equivalent of the VABS in schools for severe learning problems, the CBCL in schools for mild learning problems. A direct effect of the ABC and CBCL total scores on the VABS age equivalent was found, together with a direct effect of the VABS age equivalent on level of education and therefore an indirect effect of ABC and CBCL on level of education.

CONCLUSIONS

In the children with the highest level of mild ID, adaptive functioning seems to be the most important factor that directly influences the level of education that a child attends. Autistic and general behaviour problems directly influence the level of adaptive functioning. Especially, autistic problems seem to have such a restrictive effect on the level of adaptive functioning that children do not reach the level of education that would be expected based on IQ. Clinical implications are discussed.

Behavioral profiles and symptoms of autism in CHARGE syndrome: preliminary Canadian epidemiological data

Individuals with CHARGE syndrome were identified through the Canadian Pediatric Surveillance Program (CPSP). From this population-based cohort (n=78), we present data on developmental and behavioral characteristics for the first 13 individuals (eight males, five females) for whom assessments are complete. Standardized parent questionnaires on development and behavior were followed by a structured telephone interview, with a specific emphasis on symptoms of autistic spectrum disorder (ASD). Preliminary results confirm that individuals with CHARGE syndrome have relatively low adaptive behavior skills, motor impairments being particularly significant. Most individuals did not present with significant behavior problems; however, evidence of ASD symptoms was judged to be moderate to strong in six of the ten children who were above the age of 4-5 years. Results are discussed with reference to the challenges inherent in the diagnosis of autism in individuals with sensory impairments, and to the implications for understanding the etiology of CHARGE syndrome and of ASD.

Social skills in children with intellectual disabilities with and without autism

BACKGROUND

Social skills were studied in 363 children with mild intellectual disabilities (ID) and 147 with moderate ID with and without autism (age 4 through 18). The objective was to investigate the value of the Children's Social Behaviour Questionnaire (CSBQ), as a measure of subtle social skills, added to a measure of basic social skills with the Vineland Adaptive Behaviour Scales (VABS), in identifying children with ID with or without autism.

METHOD

Children with mild and moderate ID, with and without autistic symptomatology were compared on basic social skills, measured with the Communication and Socialization domains of the VABS, and subtle social skills, measured with the CSBQ.

RESULTS

Measuring basic social skills is not sufficient in differentiating between levels of ID. Communicative skills and subtle social skills, that concern overlooking activities or situations and fear of changes in the existing situation, seem to play a far greater role. Additionally, with respect to identifying autistic symptomatology, basic social skills do not contribute, as opposed to communicative skills and the tendency to withdraw from others.

CONCLUSIONS

The results implicate that the CSBQ not only has specific value as a measure of subtle social skills to identify pervasive developmental disorders, but that the instrument also has a specific contribution to differentiating between the two levels of ID. Furthermore, our outcomes imply a slight difference between limitations in subtle social skills as mentioned by the AAMR (American Association on Mental Retardation 2002) and limitations in subtle social skills as seen in milder forms of pervasive developmental disorders. Clinical and theoretical implications will be discussed.

A social adjustment enhancement intervention for high functioning autism, Asperger's syndrome, and pervasive developmental disorder NOS

This paper reports the findings of a 20-week social adjustment enhancement curriculum for boys aged 8-12. The curriculum was designed to address three areas hypothesized to be deficient in persons with HFA, AS, and PDDNOS: emotion recognition and understanding; theory of mind; and executive functions/real life type problem solving. Parents attended a semi-structured concurrent psychoeducational training meeting during children's sessions. Statistically significant improvements in facial expression recognition, and problem solving were reported for intervention group children compared to waiting list control group children. For the intervention group (the only group for whom data were available), older and less cognitively able boy's scores on a depression inventory decreased significantly more than younger children's. Mother's depression scores tended to decrease and there were significant reductions in child problem behaviors reported. Results are discussed in the context of individual differences in participant cognitive levels and profiles, symptom severity, and affect-related variables.

Perception and Production of Prosody by Speakers with Autism Spectrum Disorders

Speakers with autism spectrum disorders (ASD) show difficulties in suprasegmental aspects of speech production, or prosody, those aspects of speech that accompany words and sentences and create what is commonly called "tone of voice." However, little is known about the perception of prosody, or about the specific aspects of prosodic production that result in the perception of "oddness." The present study examined the perception and production of a range of specific prosodic elements in an experimental protocol involving natural speech among speakers with ASD between 14 and 21 years of age, in comparison with a typical control group. Results revealed ceiling effects limiting interpretation of findings for some aspects of prosody. However, there were significant between-group differences in aspects of stress perception and production. The implications of these findings for understanding prosodic deficits is speakers with autism spectrum disorders, and for future research in this area, are discussed.

Repetitive behaviors in autism: relationships with associated clinical features

Relationships between repetitive behaviors (RBs) and associated clinical features (i.e., cognitive and adaptive functioning levels, sleep problems, medication use, and other behavioral problems) were examined in two groups (High nonverbal IQ > or = 97 versus Low nonverbal IQ < or = 56) of children with autism spectrum disorders (n = 14; mean age = 10 years, 7 months). For the group as a whole, nonverbal cognitive ability (NVIQ) (as measured by the Leiter-R), adaptive functioning level, the presence of sleep problems, and three scales of the Aberrant Behavior Checklist (ABC) (Irritability, Lethargy, and Hyperactivity) were highly correlated with total RB scores on the Repetitive Behavior Scale-Revised (RBS-R). After controlling for NVIQ, adaptive level, sleep problems, and two scales of the ABC (Irritability and Lethargy) were not significantly associated with RB scores. However, there remained a significant positive correlation between the presence of RBs and the Hyperactivity scale of the ABC. Parent ratings of their stress levels and the presence of RBs in their children were highly correlated. The relationship between RBs and associated clinical features in autism is complex and future studies should control for cognitive ability when examining the direct and indirect relationships of these variables with RBs.

Social behavior profile in young males with fragile X syndrome: characteristics and specificity

The present study characterizes distinctive and specific features of social behavior impairment, termed social behavior profile (SBP), in young males with fragile X syndrome (FraX). Fourteen males with FraX and autism (FraX+Aut), ages 3-8 years, were compared with either 41 FraX boys without autism (Aut), 7 age-matched males with developmental language delay and autism (DLD+Aut), or with 11 boys with non-selected (for language delay) idiopathic autism (IA), on several standardized instruments assessing social behavior and autistic features (i.e., autism diagnostic interview-revised, ADI-R). We found that FraX+Aut subjects displayed more impairment in overall cognition, problem/aberrant behavior, and adaptive behavior than the rest of the FraX cohort, even when individuals with pervasive developmental disorder (PDD) were included in the latter. Compared to both DLD+Aut and IA, FraX+Aut males were less impaired in ADI-R reciprocal social interaction (RECS) domain. However, boys with FraX+Aut were in general comparable to DLD+Aut subjects in problem/aberrant and adaptive behaviors. Based on the contrast between FraX+Aut and non-autistic FraX and DLD+Aut, we were able to identify measures (e.g., child behavior checklist (CBCL) withdrawn subscale) that better define social interaction impairment in FraX. Comparisons with DLD+Aut and IA led to the conclusion that communication impairment (COMM) and stereotypic behavior contribute relatively more to the diagnosis of autism in FraX+Aut. In agreement with recent studies, our data suggest that FraX+Aut, and more generally SBP, is a distinctive subphenotype among boys with FraX, which may share some pathophysiological mechanisms with IA.

Autism

Autism is a neurologic disorder with impairments in language, social communication, and behavior, which may improve over time, but which persist throughout the lifetime. The evaluation of autism requires a separation of clinical and research objectives and is done best in close cooperation with professionals in the fields of communication, education, and psychology. There are no biologic markers of autism. Regression in language and social communication is present in approximately 30% of children with autism and is most likely to occur between 18 and 24 months of age. Early deficits in social communication can be identified by the assessment of joint attention, affective reciprocity, and metacognition. Current evidence suggests that deficits in social cognition and communication in autism may be related to dysfunction in the amygdala, hippocampus, and related limbic and cortical structures. Other neuroanatomic structures, such as the cerebellum, also may form part of a distributed neuronal network responsible for social cognition and communication. Genetics play a major role in autism, but what is inherited and how broad the inheritable phenotype is remain unclear. At a neurochemical level, the principal neurotransmitter implicated in autism is serotonin. Seizures and epileptiform discharges are common in autism and are linked to cognitive dysfunction. The role of medication is to target specific symptoms and open windows of opportunity that allow implementation of a multimodal individualized educational plan.

Factor analysis of restricted and repetitive behaviors in autism using the Autism Diagnostic Interview-R

The current study examined the factor structure of restricted and repetitive behaviors (RRB) in children with autism. Factor extraction procedures of 12 items from the Autism Diagnostic Interview-Revised (ADI-R) were applied in N = 207 individuals with autism. Two interpretable factors were identified: Factor 1--repetitive sensory motor actions and Factor 2--resistance to change. There was a significant negative correlation between an index of level of adaptive functioning and Factor 1. Intraclass correlations were not significant for either factor in a subset of families with two or more siblings with autism (multiplex). No differences in scores were apparent for either factor when multiplex families and families containing only one affected individual with autism (singleton) were compared. RRB in autism are represented by two distinct factors which may reflect two separate groups within autism. Defining subgroups within autism will allow for reduction of clinical heterogeneity and enhance our ability to dissect the genetic etiology of this complex disorder.

Correlations for the Vineland Adaptive Behavior Scales with Kaufman Brief Intelligence Test in a forensic sample

People with an intellectual disability are over-represented in the criminal justice system in many western countries. Identifying accused persons with intellectual disability is important if they are to receive protections available under the law. Accurate diagnosis is also relevant for correctional administrators, probation and parole services, and community services. Diagnosis of intellectual disability must be made on the basis of both cognitive skills (intelligence) and adaptive behavior. In this study, the Kaufman Brief Intelligence Test assessed intelligence, and the Vineland Adaptive Behavior Scales assessed adaptive behavior, through self-report. Tests were administered to 150 offenders, ranging in age from 13 to 53 years, in Australian prisons, juvenile detention centers, legal aid offices, and probation services. Pearson product-moment correlation coefficients calculated among all subtests and between total scores were significant. ROC curve analyses demonstrated that performance on each effectively predicted a standard score of less than 70 on the other one.