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TESTING VALIDITY TESTING VALIDITY AND RELIABILITY OF AND RELIABILITY OF DSM IV DSM IV

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Page 1: DSM IV- AN EVIDENCE BASED METHOD

TESTING VALIDITY TESTING VALIDITY AND RELIABILITY OF AND RELIABILITY OF

DSM IVDSM IV

Page 2: DSM IV- AN EVIDENCE BASED METHOD

THE FOLLOWING ARTICLE THE FOLLOWING ARTICLE DISCUSSES AND FOCUSES DISCUSSES AND FOCUSES

ON AUTHENTICITY OF ON AUTHENTICITY OF CLASSIFICATIONS BY DSM IVCLASSIFICATIONS BY DSM IV

Page 3: DSM IV- AN EVIDENCE BASED METHOD

AUTISM VERSUS ASPERGER’S AUTISM VERSUS ASPERGER’S SYNDROME- IS THE SYNDROME- IS THE

DIFFERENCE REAL ? CAN WE DIFFERENCE REAL ? CAN WE RELY ON DSM IV ?RELY ON DSM IV ?

Page 4: DSM IV- AN EVIDENCE BASED METHOD

Two-Year Outcome of Two-Year Outcome of Preschool Children With Autism Preschool Children With Autism

or Asperger’s Syndrome or Asperger’s Syndrome

Page 5: DSM IV- AN EVIDENCE BASED METHOD

OBJECTIVE: OBJECTIVE: DSM-IV specifies that Asperger’s disorder is a DSM-IV specifies that Asperger’s disorder is a type of pervasive developmental disorder without clinically type of pervasive developmental disorder without clinically significant cognitive or language delay. There are no data, significant cognitive or language delay. There are no data,

however, on the outcome of children with Asperger’s disorder however, on the outcome of children with Asperger’s disorder or on whether their outcome differs from that of children with or on whether their outcome differs from that of children with

autism. The objectives of this study were to compare the autism. The objectives of this study were to compare the outcome of groups of children with these disorders over a outcome of groups of children with these disorders over a period of 2 years on variables independent of the defining period of 2 years on variables independent of the defining

criteria and to identify variables that might account for these criteria and to identify variables that might account for these

differencesdifferences

Page 6: DSM IV- AN EVIDENCE BASED METHOD

METHOD: METHOD: All children 4–6 years of age who All children 4–6 years of age who came for assessment or were currently in came for assessment or were currently in treatment at a pervasive developmental treatment at a pervasive developmental

disorder service of one of several centers in disorder service of one of several centers in a large geographic region were identified. a large geographic region were identified.

Children who received a diagnosis of autism Children who received a diagnosis of autism (N=46) or Asperger’s syndrome (N=20) on (N=46) or Asperger’s syndrome (N=20) on the basis of a diagnostic interview and had the basis of a diagnostic interview and had

an IQ in the nonretarded range were given a an IQ in the nonretarded range were given a battery of cognitive, language, and battery of cognitive, language, and

behavioral tests. Families were contacted behavioral tests. Families were contacted roughly 2 years after the date of their roughly 2 years after the date of their

enrollment in the study, and many of the enrollment in the study, and many of the tests were readministeredtests were readministered

Page 7: DSM IV- AN EVIDENCE BASED METHOD

CONCLUSIONS: CONCLUSIONS: Although the Although the exact mechanism for the exact mechanism for the

differences in outcome remain differences in outcome remain to be determined, it appears to be determined, it appears that Asperger’s disorder and that Asperger’s disorder and autism represent parallel but autism represent parallel but

potentially overlapping potentially overlapping developmental trajectories developmental trajectories

Page 8: DSM IV- AN EVIDENCE BASED METHOD

Children with Children with pervasive pervasive developmental disordersdevelopmental disorders

demonstrate qualitative demonstrate qualitative impairments in impairments in reciprocal reciprocal social interactionsocial interaction and in and in verbal and nonverbal verbal and nonverbal

communicationcommunication and engage and engage in a in a pattern of repetitive, pattern of repetitive,

stereotypic activities (DSM-stereotypic activities (DSM-IV).IV).

Page 9: DSM IV- AN EVIDENCE BASED METHOD

Pervasive developmental Pervasive developmental disorder" is a general term disorder" is a general term referring to a spectrum of referring to a spectrum of disorders that differ with disorders that differ with

respect to the respect to the number or number or type of symptoms or age at type of symptoms or age at

onsetonset. .

Page 10: DSM IV- AN EVIDENCE BASED METHOD

Autism is the best-known Autism is the best-known example of a pervasive example of a pervasive developmental disorder developmental disorder

subtype, but, through the subtype, but, through the years, a years, a number of other number of other

subtypessubtypes have been proposed have been proposed as well. as well.

Page 11: DSM IV- AN EVIDENCE BASED METHOD

These include These include atypical atypical autism, Asperger’s autism, Asperger’s

disorder, and disintegrative disorder, and disintegrative disorder (DSM-IVdisorder (DSM-IV). The ). The

diagnostic boundary between diagnostic boundary between autism and each of these other autism and each of these other subtypes is unclear and varies subtypes is unclear and varies according to the classification according to the classification

scheme scheme

Page 12: DSM IV- AN EVIDENCE BASED METHOD

The key features that The key features that distinguish autism from distinguish autism from

Asperger’s disorder are that Asperger’s disorder are that the latter is characterized the latter is characterized by a by a lack of clinically significant lack of clinically significant

language and cognitive language and cognitive delaydelay (DSM-IV and ICD-10). (DSM-IV and ICD-10).

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However, the data on whether However, the data on whether Asperger’s disorder is a valid Asperger’s disorder is a valid

subtype of pervasive subtype of pervasive developmental disorder are developmental disorder are

both limited and both limited and inconsistentinconsistent

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Now that many more children Now that many more children are receiving this diagnosis, are receiving this diagnosis,

outcome studies are essential outcome studies are essential to evaluate the to evaluate the clinical clinical

usefulness of the categoryusefulness of the category and and to provide information to provide information

to parentsto parents. .

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Asperger’s disorder have Asperger’s disorder have better language and better language and

socialization scoressocialization scores and and fewer autistic behaviors fewer autistic behaviors than children with high-than children with high-functioning autism,functioning autism, but but whether this is a whether this is a useful useful

distinctiondistinction depends, in part, depends, in part, on outcome evaluations.on outcome evaluations.

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The primary outcome variables The primary outcome variables were measures of were measures of social social

competence and a competence and a composite measure of composite measure of

autistic symptomsautistic symptoms, variables , variables that were not used in the initial that were not used in the initial

clinical distinction but are clinical distinction but are clinically relevant to long-term clinically relevant to long-term

outcome outcome

Page 17: DSM IV- AN EVIDENCE BASED METHOD

the strong differences between the strong differences between the groups of Asperger’s and the groups of Asperger’s and

Autism at 4–6 years of age Autism at 4–6 years of age were still present or had were still present or had

attenuatedattenuated, ,

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children with Asperger’s children with Asperger’s disorder have disorder have lessless visual- visual-

spatial and motor ability than spatial and motor ability than children with autism, we children with autism, we

wanted to see whether this wanted to see whether this difference had emerged difference had emerged at 6–8 at 6–8 years of age, even though years of age, even though

we had not seen this at 4–6 we had not seen this at 4–6 yearsyears

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we used criteria that are we used criteria that are different from those of DSM-IV different from those of DSM-IV

and ICD-10, children in our and ICD-10, children in our study group are described as study group are described as

having Asperger’s "syndrome" having Asperger’s "syndrome" rather than Asperger’s rather than Asperger’s

"disorder." "disorder."

Page 20: DSM IV- AN EVIDENCE BASED METHOD

Our criteria for Asperger’s syndrome Our criteria for Asperger’s syndrome are consistent with, but not identical are consistent with, but not identical to, the ICD-10 and DSM-IV criteria for to, the ICD-10 and DSM-IV criteria for

Asperger’s disorder, which were Asperger’s disorder, which were published after data collection was published after data collection was

completed. In fact, strictly applying the completed. In fact, strictly applying the DSM-IV criteria (as operationalized in DSM-IV criteria (as operationalized in

the Autism Diagnostic Interview the Autism Diagnostic Interview algorithm) would have resulted in only algorithm) would have resulted in only one child receiving a DSM-IV diagnosis one child receiving a DSM-IV diagnosis

of Asperger’s disorderof Asperger’s disorder

Page 21: DSM IV- AN EVIDENCE BASED METHOD

To qualify for a diagnosis of Asperger’s To qualify for a diagnosis of Asperger’s syndrome, the child had to have at least syndrome, the child had to have at least

one exampleone example of an impairment in of an impairment in reciprocal social interaction (as opposed to reciprocal social interaction (as opposed to autism, which stipulates that there must be autism, which stipulates that there must be

at least at least two examplestwo examples in this area), at least in this area), at least one example of an impairment in verbal or one example of an impairment in verbal or

nonverbal communication (same as for nonverbal communication (same as for autism), and at least one example of a autism), and at least one example of a

repetitive, stereotyped behavior (same as repetitive, stereotyped behavior (same as for autism). These qualifications were for autism). These qualifications were

specified by using the items from the Autism specified by using the items from the Autism Diagnostic Interview diagnostic algorithm for Diagnostic Interview diagnostic algorithm for

autismautism

Page 22: DSM IV- AN EVIDENCE BASED METHOD

Moreover, the diagnosis of Moreover, the diagnosis of Asperger’s syndrome required an Asperger’s syndrome required an

absence of clinically absence of clinically significant language delaysignificant language delay (i.e., (i.e., spontaneous phrase speech by spontaneous phrase speech by 36 36 months of agemonths of age) and an ) and an absence absence

of marked or persistent of marked or persistent deviant languagedeviant language development development

such as delayed echolalia, such as delayed echolalia, pronoun reversal, and neologisms pronoun reversal, and neologisms (coded as 2 or 3) on these items (coded as 2 or 3) on these items

from the Autismfrom the Autism

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In contrast, children with the In contrast, children with the diagnosis of autism diagnosis of autism spoke spoke

after 36 monthsafter 36 months and/orand/or had had evidence of evidence of marked deviance marked deviance

in language developmentin language development (as defined for Asperger’s (as defined for Asperger’s syndrome) and met the syndrome) and met the

diagnostic algorithm for autism diagnostic algorithm for autism as specified by Le Couteur et al as specified by Le Couteur et al

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ProcedureProcedure

Page 25: DSM IV- AN EVIDENCE BASED METHOD

The time 1 assessment The time 1 assessment consisted of two IQ tests, tests consisted of two IQ tests, tests

of language and nonverbal of language and nonverbal abilities, a semistructured abilities, a semistructured

interview (the Autism interview (the Autism Diagnostic Interview ), the Diagnostic Interview ), the Autism Behavior Checklist , Autism Behavior Checklist , and the Vineland Adaptive and the Vineland Adaptive

Behavior Scales Behavior Scales

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Families were contacted Families were contacted roughly 2 years after the date roughly 2 years after the date of their enrollment in the study of their enrollment in the study (mean=26 months, range=21–(mean=26 months, range=21–

30). The assessment 30). The assessment conducted at follow-up conducted at follow-up

included a full psychometric included a full psychometric battery, parent-completed battery, parent-completed

questionnaires, and structured questionnaires, and structured interviews interviews

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All follow-up assessments were All follow-up assessments were administered by a different administered by a different research assistant than the research assistant than the

one who did the original one who did the original assessments, thus maintaining assessments, thus maintaining

blindness blindness

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AnalysisAnalysis

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First, the competence in First, the competence in socialization (Vineland Adaptive socialization (Vineland Adaptive

Behavior Scales socialization Behavior Scales socialization scale) and the number of scale) and the number of

autistic/pervasive developmental autistic/pervasive developmental disorder symptoms (the Autism disorder symptoms (the Autism Behavior Checklist) of the two Behavior Checklist) of the two

groups at follow-up were groups at follow-up were compared by using a simple compared by using a simple analysis of variance (ANOVAanalysis of variance (ANOVA))

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To test for differences in the To test for differences in the secondary outcome variables, secondary outcome variables,

a multivariate analysis of a multivariate analysis of variance (MANOVA) was run on variance (MANOVA) was run on

the language tests, the the language tests, the Vineland communication scale, Vineland communication scale,

and the visual-spatial and the visual-spatial measures at follow-up measures at follow-up

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Results Results

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The groups of children with autism and The groups of children with autism and Asperger’s syndrome were compared Asperger’s syndrome were compared

first on the socialization score from the first on the socialization score from the Vineland Adaptive Behavior Scales. Vineland Adaptive Behavior Scales. Both groups had low scores on the Both groups had low scores on the

socialization measure, but the children socialization measure, but the children with Asperger’s syndrome had higher with Asperger’s syndrome had higher scores than the children with autism scores than the children with autism

(75.6 versus 61.8).(75.6 versus 61.8).

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On the communication scale On the communication scale and the language tests (and the language tests (Table 2Table 2, the children with , the children with

Asperger’s syndrome usually Asperger’s syndrome usually obtained scores within a obtained scores within a standard deviation of the standard deviation of the

population mean, whereas the population mean, whereas the children with autism usually children with autism usually obtained scores at least two obtained scores at least two standard deviations below standard deviations below

normalnormal

Page 34: DSM IV- AN EVIDENCE BASED METHOD

When the groups were When the groups were compared on the measures of compared on the measures of visual-motor and visual-spatial visual-motor and visual-spatial

abilities, no significant abilities, no significant differences emerged even differences emerged even

without controlling for without controlling for measures taken at study measures taken at study

enrollment enrollment

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DiscussionDiscussion

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there was a clear distinction there was a clear distinction between primary and between primary and

secondary outcome measures, secondary outcome measures, and a wide range of outcomes and a wide range of outcomes was assessed, including some was assessed, including some

measures that could be measures that could be administered at both the administered at both the

beginning of the study and at beginning of the study and at 2-year follow-up. 2-year follow-up.

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It is true, however, that the It is true, however, that the outcome differences can be outcome differences can be

explained by initial differences explained by initial differences on Vineland Adaptive Behavior on Vineland Adaptive Behavior Scales socialization scores and Scales socialization scores and

the composite measure of the composite measure of autistic symptomsautistic symptoms

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This suggests that both This suggests that both subtypes of pervasive subtypes of pervasive

developmental disorder are developmental disorder are following similar following similar

developmental pathways but developmental pathways but that the autistic children are that the autistic children are

simply behind the children with simply behind the children with Asperger’s syndrome; that is, Asperger’s syndrome; that is,

the pathways are parallel. the pathways are parallel.

Page 39: DSM IV- AN EVIDENCE BASED METHOD

The classification of children with The classification of children with autism has a long a varied history autism has a long a varied history (33)(33). . Perhaps the most useful distinction is Perhaps the most useful distinction is between autistic children above and between autistic children above and

below the IQ cutoff for mental below the IQ cutoff for mental retardation. The data reported in this retardation. The data reported in this

study indicate that another useful study indicate that another useful clinical distinction may be between clinical distinction may be between

children with high-functioning children with high-functioning pervasive developmental disorder with pervasive developmental disorder with

different levels of language different levels of language developmentdevelopment

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No doubt this will have to await No doubt this will have to await a clearer a clearer understanding of understanding of the geneticsthe genetics of pervasive of pervasive

developmental disorder and developmental disorder and the mechanism for the the mechanism for the

variation in language deficits. variation in language deficits.

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Rather, the results reported here Rather, the results reported here indicate that the clinical distinction indicate that the clinical distinction

between autism and Asperger’s between autism and Asperger’s syndrome does have prognostic syndrome does have prognostic

importance, although it may be more importance, although it may be more useful to think of the pervasive useful to think of the pervasive

developmental disorder subtypes in developmental disorder subtypes in terms of different developmental terms of different developmental

trajectories than to argue that they trajectories than to argue that they represent different disorders or are on represent different disorders or are on

a continuum of severitya continuum of severity

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