Diagnosis and Differential Diagnosis of Asperger Syndrome

7/30/2019 Diagnosis and Differential Diagnosis of Asperger Syndrome

1/10

10.1192/apt.7.4.310Access the most recent version at DOI:

2001, 7:310-318.APTMichael Fitzgerald and Aiden CorvinDiagnosis and differential diagnosis of Asperger syndrome

Referenceshttp://apt.rcpsych.org/content/7/4/310#BIBLThis article cites 0 articles, 0 of which you can access for free at:

permissionsReprints/

[email protected] obtain reprints or permission to reproduce material from this paper, please write

to this article atYou can respond http://apt.rcpsych.org/cgi/eletter-submit/7/4/310

fromDownloaded

The Royal College of PsychiatristsPublished byon May 8, 2013http://apt.rcpsych.org/

http://apt.rcpsych.org/site/subscriptions/go to:Adv. Psychiatr. Treat.To subscribe to
http://apt.rcpsych.org/http://apt.rcpsych.org/


2/10

APT (2001), vol. 7, p. 310 Fitzgerald & CorvinAdvances in Psychiatric Treatment (2001), vol. 7, pp. 310318

Asperger syndrome is an uncommon condition, butprobably more common than classic autism (the onlypublished population study estimated prevalence at36 per 10 000 children for Asperger syndrome and5 per 10 000 for autism (Ehlers & Gillberg, 1993)).

Misdiagnosis or delayed diagnosis of this disorderis a serious problem, and the average age at diagnosisis several years later than for autism (Gillberg, 1989).Obviously, this can be traumatic for individuals andfamilies; furthermore, the most effective interventionprogrammes begin early, and establishing manage-ment strategies at an early age can minimise later

behavioural problems (Howlin, 1998).In 1944 Hans Asperger described a condition he

termed autistic psychopathy, characterised byproblems in social integration and non-verbalcommunication associated with idiosyncratic verbalcommunication and an egocentric preoccupationwith unusual and circumscribed interests. Patients

with this condition had difficulties with empathyand intuition and had a tendency to intellectualis-ation. They were also clumsy (5090% had motorcoordination problems), found it hard to take partin team sports and exhibited behavioural difficultiesincluding aggression and being victims of bullying.Asperger did not provide diagnostic criteria for thiscondition and it remained obscure until a reviewarticle by Lorna Wing in 1981.

Wing renewed interest in the condition, whichshe renamed Asperger syndrome, and described thefollowing difficulties in the first 2 years of life ofchildren with the condition:

(a) a lack of normal interest and pleasure inpeople around them;

(b) a reduction in the quality and quantity ofbabbling;

(c) a significant reduction in shared interests;(d) a significant reduction in the wish to

communicate verbally or non-verbally;

(e) a delay in speech acquisition andimpoverishment of content;(f) no imaginative play or imaginative play

confined to one or two rigid patterns.

A number of authors have subsequently suggesteddiagnostic criteria, but the six proposed by Gillberg(1991) are, arguably, closest to Asperger s originaldescription of the syndrome (Box 1). Inclusion of thesyndrome in both international diagnostic systems(ICD10 (World Health Organization, 1992) andDSMIV (American Psychiatric Association, 1994))has resulted in broad clinical recognition of the diag-nosis, but also in confusion. Asperger syndrome has

been renamed Asperger disorder in DSMIV, andthe criteria of both differ from Gillbergs criteria andAspergers original description of the syndrome.

Diagnosis and differential diagnosisof Asperger syndrome

Michael Fitzgerald & Aiden Corvin

Michael Fitzgerald is Henry Marsh Professor of Child Psychiatry at Trinity College Dublin (Child and Family Centre, BallyfermotRoad, Ballyfermot, Dublin 10, Ireland. Tel: +353 1 626 7512; fax: +353 1 454 4418; e-mail: [email protected]). His primary researchinterests are autism and autistic spectrum disorders. Aiden Corvin is a Wellcome Trust Research Fellow in Mental Health at theDepartment of Psychiatry at Trinity Centre for Health Sciences, St. Jamess Hospital, Dublin. Dr Corvin was formerly aregistrar in child psychiatry at the Child and Family Centre, Ballyfermot. His research interests include autism spectrumdisorders and psychiatric genetics, particularly of psychotic disorders.

Box 1 Gillbergs (1991) diagnostic criteria forAsperger syndrome

Social impairmentsNarrow interestsRepetitive routinesSpeech and language peculiaritiesNon-verbal communication problems

Motor clumsiness


3/10

Diagnosis of Asperger syndrome APT (2001), vol. 7, p. 311

The DSMIV diagnosis is based on impairmentof social interaction and the presence of stereo-typical or repetitive behaviours (Box 2). Diagnosisrequires that the impairment is clinically significant,occurs before 3 years of age and excludes clinicallysignificant delay in language, cognition or otherskills. The ICD10 research criteria (World HealthOrganization, 1993) are virtually identical. By

excluding speech and language difficulties, theDSM definition of Asperger disorder is narrowerthan Asperger syndrome as defined by Wing orGillberg and would exclude some of the originalcases described by Hans Asperger. As the vastmajority of persons with Asperger disorder/syn-drome do have speech and language abnormalitiesit was hoped that future text revisions of DSMIVmight correct this anomaly. Indeed, the recent DSMIVTR guides that the occurrence ofno clinicallysignificant delays in language does not imply thatindividuals with Asperger Disorder have noproblems with communication (American Psychi-atric Association, 2000, p. 80). Examples given

include unusual verbosity or subtle abnormalities ofsocial communication (such as turn-taking in con-versation). We feel that DSMIVTR draws attentionto the issue, but underestimates the languagedifficulty involved. This paper examines the differ-ential diagnosis of Asperger syndrome (Wing, 1981)and disorder (American Psychiatric Association,1994), beginning with the more common and finishwith the less common causes of diagnostic confusion.

Differential diagnosis

Other pervasive developmentaldisorders (PDD)

Autism/autism spectrum disorders (DSMIV)

Autism shares the same DSM criteria for abnormalsocial interaction and behaviour as Aspergerdisorder, but requires additional impairments incommunication (Box 3). Delay or impairment insocial interaction, communication or behaviourmust arise before age 3 years. In DSMIV, if bothautism and Asperger disorder diagnoses can bemade, the autism diagnosis takes precedence. UnlikeAsperger disorder (which excludes individuals withdelays in cognitive abilities or other skills), autismcan occur at all levels of ability: the majority (70%)of cases have associated learning disabilities andalmost half have an IQ below 50.

In a prevalence study of autism, Wing & Gould(1979) identified a large number of children whofailed to meet the diagnostic criteria for classicautism, but had a triad of impairments involvingsocial interaction, communication and imagination,with additional repetitive stereotyped activities. Thistriad of symptoms, termed the autistic spectrum,was recognised at all levels of intelligence and isincluded in DSMIV as pervasive developmental

Box 2 DSMIV criteria for the diagnosis of Asperger disorder

A. Qualitative impairment in social interaction, as manifested by at least two of the following:

(1) marked impairment in the use of multiple nonverbal behaviors such as eye-to-eye gaze,facial expression, body postures, and gestures to regulate social interaction

(2) failure to develop peer relationships appropriate to developmental level

(3) a lack of spontaneous seeking to share enjoyment, interests, or achievements with otherpeople (e.g., by a lack of showing, bringing, or pointing out objects of interest to other people)

(4) lack of social or emotional reciprocity

B. Restricted repetitive and stereotyped patterns of behavior, interests, and activities, as manifestedby at least one of the following:

(1) an encompassing preoccupation with one or more stereotyped and restricted patterns ofinterest that is abnormal either in intensity or focus

(2) apparently inflexible adherence to specific, nonfunctional routines or rituals(3) stereotyped and repetitive motor mannerisms (e.g., hand or finger flapping or twisting, or

complex whole-body movements)(4) persistent preoccupation with parts of objects

(American Psychiatric Association, 1994: p. 77)

This disturbance must be clinically significant, but without clinically significant language delay ordelay in cognitive development or other skills


4/10

APT (2001), vol. 7, p. 312 Fitzgerald & Corvin

disorder not otherwise specified, and in ICD10 as

atypical autism, other pervasive developmentaldisorders or pervasive developmental disorders,unspecified. The estimated prevalence of autismspectrum disorders (autistic spectrum disorders)may be as high as 91 per 10 000.

At present it is not clear whether Aspergersyndrome is distinct from the autistic spectrumdisorders. Diagnostic uncertainty arises in patientsof near normal cognitive ability (total IQ >70) withautistic spectrum disorders, who are described ashaving high-functioning autism (HFA). Differencesare reported between Asperger syndrome and HFA,for example, verbal skills being significantly greaterthan non-verbal ones in Asperger syndrome the

opposite of the pattern reported in HFA. Thisdifferentiation may be simplistic, as it depends onthe diagnostic system used. A sample defined usingWing or Gillberg criteria for Asperger syndromewould include children with abnormal or delayedlanguage and, by definition, worse verbal skills thana DSM or ICD sample, which would exclude theseindividuals. Attempts to separate Asperger syn-drome or HFA categorically based on presence orabsence of language delay are artificial. Comparisonstudies have also failed to control adequately for IQdifferences between samples in many cases. Currentresearch data do not convincingly support the

separation of Asperger syndrome and the autisticspectrum disorders as distinct disorders. BothAsperger syndrome and autistic spectrum disordersare about five times more common in boys than ingirls; segregate within the same families; appearstrongly genetic (American Psychiatric Association,2000); and share similar comorbidity (Gillberg &Billstedt, 2000). If autism and Asperger syndromediffer at all, it is in the degree of impairment ratherthan in having discrete, specific and independent

features. This is supported by outcome studies; both

are associated with social difficulties persisting intoadulthood, but these are less severe in Aspergersyndrome. Combining Asperger syndrome andautistic spectrum disorders into an autistic spectrumis a better way forward.

In addition to the diagnostic criteria mentioned, anumber of assessment instruments are available orin development for use with people with Aspergersyndrome. These include the Asperger SyndromeScreening Questionnaire (ASSQ; Ehlers et al, 1999)and the Pervasive Developmental Disorder Ques-tionnaire (PDDQ; Baron-Cohen et al, 1996). TheASSQ is designed for completion by parents orteachers to screen for Asperger syndrome and other

high-functioning autism spectrum disorders inschool-age children. The PDDQ is an 18-itemquestionnaire for parents, which includes questionsspecifically designed to identify clinical character-istics of Asperger syndrome.

These instruments were all designed for screeningpurposes, not to differentiate Asperger syndromefrom HFA, but to identify higher-functioningindividuals within the autistic spectrum. Eachrequires further work to fulfil psychometric require-ments for sensitivity, specificity, reliability andvalidity. Of existing instruments used for the diag-nosis of autistic spectrum disorders, the Autism

Diagnostic Interview Revised (ADIR; Lord et al,1994) may be useful in assessing individuals forAsperger syndrome. This instrument consists ofthree scales corresponding to the social, commun-ication and behavioural impairments and is basedon parent report. The Autism Diagnostic Obser-vational Schedule Generic (ADOSG; Lord et al,1999), a supplementary standardised interview andobservational assessment may also be helpful.Accurate diagnosis in younger children (under 2

Box 3 Additional DSMIV criteria for autism

Must meet criteria A and B in Box 1, but in addition:

Qualitative impairments in communication as manifested by at least one of the following:

(a) delay in, or total lack of, the development of spoken language (not accompanied by an attemptto compensate through alternative modes of communication such as gesture or mime)

(b) in individuals with adequate speech, marked impairment in the ability to initiate or sustain aconversation with others

(c) stereotyped and repetitive use of language or idiosyncratic language(d) lack of varied, spontaneous make-believe play or social imitative play appropriate to

developmental level(American Psychiatric Association, 1994: p. 70)

A total of six items from the social, communication and behavioural criteria are required. Delay in atleast one of these domains must occur before age 3 years


5/10


years of age) is difficult, despite the neurodevelop-mental nature of these disorders. The Checklist forAutism in Toddlers (CHAT; Baird et al, 2000) mayprove useful in identifying children at risk. Howlin(2000) provides a more extensive appraisal ofavailable assessment instruments. Full assessmentof Asperger syndrome requires a multi-disciplinaryapproach, as outlined in Box 4.

Pervasive developmental disorder not otherwisespecified (DSMIV)

Another diagnosis of relevance is pervasivedevelopmental disorder not otherwise specified(PDDNOS). This is characterised by a severe andpervasive impairment in the development ofreciprocal social interaction or verbal and non-verbal communication skills or when stereotyped

behaviour, interests and activities are present(American Psychiatric Association, 1994: p. 77).This category in DSMIV needed revision as theinclusion of the word or twice greatly diluted itsmeaning and grossly widened it as a category. DSMIVTR has corrected this error, requiring there to bean impairment in reciprocal social interactionassociated with an impairment in communicationskills or with stereotyped behaviour, interests oractivities. In the past, particularly in the USA,PDDNOS was used as a synonym for Aspergersyndrome, although for parents this title is unhelpfuland confusing.

Other pervasive developmental disorders

(DSMIV)

Neither Rett disorder nor childhood disintegrativedisorder are part of the autistic spectrum, and theyare unlikely to represent sources of diagnosticconfusion. Rett disorder is most common in girlsand is characterised by apparently normal develop-ment in the first 5 months of life, with subsequentdeceleration of head growth, loss of previouslyacquired hand skills, loss of social engagement,

poorly coordinated gait and language problems(American Psychiatric Association, 2000). Similarly,childhood disintegrative disorder presents with lossof language, motor skills and bowel and bladdercontrol following a 2-year history of normaldevelopment (American Psychiatric Association,2000). In each case the diagnosis should be excluded

by a detailed developmental history and physicalexamination.

Schizophrenia spectrum disorders

Schizophrenia (DSMIV)

Schizophrenia is a disorder in which psychoticsymptoms (delusions or hallucinations), thoughtdisorder and so called negative symptoms causesocial and/or occupational dysfunction over time.Because individuals with Asperger syndrome havenormal cognitive ability, restrictive behaviours and

impairments in social interaction and communic-ation can be misinterpreted as evidence of schizo-phrenia. People with Asperger syndrome havedifficulty understanding the subtleties of social

behaviour, but this should not be confused withevidence of psychotic disorder. In a clinical setting,asking individuals with Asperger syndromewhether they hear voices may induce a positiveresponse, and they might concur that they hearvoices when people arent there, but they may berefering to the voices of people in an adjacent room.Deficiencies in concrete thinking and in understan-ding how other minds think may cause patients withAsperger syndrome to misinterpret what is said to

them, and they might as a result be labelledparanoid. Misinterpreting social contacts can alsolead to inappropriate emotional responses, contrib-uting to this impression. Persons with Aspergersyndrome sometimes speak their thoughts out loud,which again can be misinterpreted by a psychiatrist.

Language abnormalities associated with autisticspectrum disorders include substitutions, literal-ness, problems with prosody, staccato speech andmonotonous speech that is excessively pedantic andfocused on details or obsessive questions. A tendencyto direct the conversation towards obsessions couldeasily be mistaken for evidence of associative

loosening. A comparison of thought disorder andaffective flattening in patients with autism and withschizophrenia found that they did not differ in termsof affective flattening, and that adult patients withautism showed poverty of speech, poverty of contentand perseveration (Ramsey et al, 1986). The autismgroup showed significantly less derailment andillogicality, suggesting that they would be unlikelyto meet DSM or ICD criteria for thought disorder inschizophrenia.

Box 4 Assessment of Asperger syndrome

Assessment should include:A medical examination to exclude medical

causes, e.g. sensory impairmentsA laboratory workup (to exclude fragile-X

syndrome, for example)Psychiatric evaluation for comorbidityPsychological assessment (including IQ

assessment)Speech and language assessment


6/10


Social and communication deficits can beinterpreted as evidence of negative symptomatology,so it is important when assessing functioning toestablish premorbid ability. These conditionsobviously differ in age at onset, developmentalhistory and mental state examination. In DSMIV,pervasive developmental disorder is an exclusion

condition for schizophrenia and it should besuspected in atypical or non-responsive cases.Schizophrenia can co-occur in autistic spectrumdisorders, but the additional diagnosis is made onlyif prominent delusions or hallucinations are presentfor at least 1 month (less with treatment). Despite anabsence of epidemiological studies of psychiatriccomorbidity in autistic spectrum disorders, it has

been suggested that delusions or auditory hallucin-ations may be more common than in the generalpopulation, but the prevalence of schizophrenia (at0.6 %) is comparable to general population levels.

Bleuler (1911), founder of the modern concept ofschizophrenia, described four primary symptoms

necessary for the disorder (the four As): ambivalence,loosening of associations, disturbance of affect andautism, which he defined as dependence on aninternal unrealistic world. Both he and Kraepelin(1919) defined subgroups with social withdrawaland affective flattening, oddness and eccentricity,

being timid with a narrow circle of interests andcold relations to companions, and lacking sympathyor attachment. From these descriptions the conceptof simple schizophrenia, considered by some to be adiagnostic waste-basket, entered the lexicon. Thesymptoms described are equally applicable toautistic spectrum disorders, and the subtype simple

schizophrenia has been removed from DSMIV. Itsretention in ICD10 is a likely source of diagnosticconfusion.

Schizoid personality in childhood (DSM-IV)

Schizoid personality in childhood is defined bysolitariness, lack of empathy, emotional detachment,increased sensitivity, at times paranoid ideation, andsingle-minded pursuit of special interests. All thesefeatures are seen in Asperger syndrome, andcomorbid issues (depression or behaviour problemsin particular) are likewise similar for both con-ditions. On the basis of evidence presented in Wolffs

(1998) discussion of schizoid personality inchildhood, we have concluded that there issignificant overlap between schizoid personality inchildhood and Asperger syndrome.

Schizotypal personality disorder (DSMIV)

The DSMIV diagnosis of schizotypal personalitydisorder depends on odd beliefs or magical think-ing, bizarre fantasies or preoccupations, odd

thinking and speech, odd, eccentric or peculiarbehaviour and appearance, lack of close friends andsocial anxiety. All of these criteria can also occur inAsperger syndrome, and Wolff (1998) regardsAsperger syndrome and schizoid/schizotypaldisorders as interchangeable terms that identifyroughly the same group of children. The conditions

do differ in at least three important respects. First,there appears to be an increased rate of develop-ment of schizophrenia in schizotypal personalitydisorder. Second, schizotypal personality disorderand schizophrenia co-occur in families andappear genetically related. Third, prospectiveresearch of children at high risk of schizophrenia(Erlenmeyer-Kimling et al, 2000) suggests thatsome individuals later diagnosed with schizo-typal personality disorder developed withoutimpairments in reciprocal social interaction andcommunication.

Attention-deficit hyperactivitydisorder (DSMIV)

Attention-deficit hyperactivity disorder (ADHD)presents with inattention, distractability, fidgetiness,impulsivity and hyperactivity. Persons with HFAspectrum disorders may be hyperactive, impulsive,have a short attention span and share similarexecutive function deficits as patients with ADHD.The conditions differ in that ADHD lacks the classicimpairment in reciprocal social interaction, narrowinterests, repetitive routines and non-verbalproblems of Asperger syndrome. In accordance with

a hierarchical rule in DSMIV, a person meeting thecriteria for a pervasive developmental disordercannot be diagnosed as having ADHD. This is notthe case in ICD10, in which a dual diagnosis ofAsperger syndrome and ADHD is possible.

Gillberg & Ehlers (1998) point out that childrenwho meet criteria for ADHD may also meet the fullcriteria for Asperger syndrome. They mention onestudy, in which 21% of children with severe ADHDmet the full criteria for Asperger syndrome and 36%showed autistic traits. A developmental history isusually sufficient to separate ADHD from Aspergersyndrome, but ADHD can present as soon as the

child can walk, and it is important to consider thatimpulsivity can interfere with social relationships,making children appear unempathic. Indeed,children with ADHD can be so easily distracted thatthey appear to be in a world of their own andtherefore seem socially disconnected. It is notsurprising, therefore, that children with Aspergersyndrome are not uncommonly misdiagnosed ashaving ADHD, since it is often the attention andhyperactive problems that parents first observe.


7/10


Obsessive compulsive disorders(DSMIV)

The core features of obsessivecompulsive disorder(OCD) are recurrent and persistent thoughts,impulses or images that are experienced at sometime during the disturbance as intrusive andinappropriate and that cause marked anxiety ordistress. The individual recognises that these are aproduct of his or her own mind. Compulsionsinvolve repetitive behaviours or mental acts that aperson feels driven to perform to reduce stressassociated with some dreaded event or situation.An adult can recognise that they are excessive orunreasonable, but children cannot (AmericanPsychiatric Association, 1994).

These phenomena, including the urge to countand manipulate numbers, to repeat the same actionover and over, are similar to the repetitive routinesassociated with Asperger syndrome. Individuals

with both conditions display ritualistic behaviourand resistance to change. Where they differ is thatpersons with Asperger syndrome have obsessiveinterests that are not experienced as ego-dystonicand, indeed, are often enjoyed. Baron-Cohen (1989)was critical of the use of the term obsession inpersons with autism because the subjective phenom-ena of resistance to repetitive activities could not bediscerned in autism. He suggested instead thephrase repetitive activities. OCD generally has amuch later onset and lacks the poor social emotionalreciprocity, empathy problems and social skillsdifficulties of people with Asperger syndrome(Szatmari, 1998). Detailed analysis of currentsymptoms and an early developmental history arethe key to making a correct diagnosis.

Affective disorders

Despite some overlap in symptomatology (includingsocial withdrawal, lack of emotional response andloss of interest in relationships), affective disordersdiffer in representing a distinct change from pre-morbid functioning, and typically are associatedwith onset in adulthood. Epidemiological studies ofpsychiatric comorbidity are lacking in individuals

with autistic spectrum disorders, but depression,anxiety disorders and bipolar disorder occur morecommonly than in the general population and repre-sent substantial morbidity (Gillberg & Billstedt, 2000).

Other diagnostic categories

Many other overlapping categories are unrepresen-ted in DSMIV or ICD10 and may be a source of

confusion for families and professionals alike. Termssuch as semantic pragmatic disorder, non-verballearning difficulty and developmental learningdisability of the right hemisphere have arisen asdifferent specialities have struggled independentlyto categorise individuals with social disabilities whodo not meet criteria for classic autism.

Semantic pragmatic disorder

Semantic pragmatic disorder (Rapin & Allen, 1983)is probably not an uncommon cause of misdiag-nosis. Children with autistic spectrum disordersoften have some language difficulties and many willattend a speech therapist in the first instance andreceive a diagnosis of semantic pragmatic disorder.This is characterised by near-normal vocabulary,grammar, and phonology, but language use isabnormal in content and function and comprehen-sion is also impaired. There are considerabledifficulties in initiating or sustaining a conver-

sation, making cohesive links in conversation fromtopic to topic, and words are used out of context(Szatmari, 1998: p. 71). Is this an exact descriptionof the language problems of Asperger syndrome(Wing, 1981)? These describe pragmatic languagedifficulties. Wings criterion for a reduction inquality and quantity of babbling refers to expressivelanguage difficulties; a delay in speech acquisitionand impoverishment of content are receptiveexpressive language problems; and defectiveimaginative play is a receptivepragmatic languagedifficulty. The definition of semantic pragmaticdisorder includes no reference to problems of socialand emotional interaction or to repetitive andstereotyped patterns of behaviour. The existence ofsemantic pragmatic disorder as a separate entitywith clinical validity is questionable.

Deficits in attention, motor control andperception

The core features of deficits in attention, motorcontrol and perception (DAMP; Gillberg et al, 1982)include a cross-situational disturbance of attention,gross and fine motor dysfunction and perceptualdysfunctions not accounted for by associated mentalretardation or cerebral palsy. DAMP and Aspergersyndrome are similar and can occur together.Overlapping features include: the condition beingmore common in boys, perceptual problems, a failureto adjust volume and pitch of voice and motorclumsiness (although the latter is not recognised inthe Asperger disorder criteria). Whether theyrepresent the same population is uncertain, asattention difficulties are not part of the definition ofeither Asperger syndrome or disorder, and neitherare associated with delay in cognitive development.


8/10


DAMP can also have significant speech andlanguage difficulties, e.g. articulation problems,hypotonia of the mouth and certain variants ofstuttering. Heredity appears to play a much lesserrole in DAMP than in Asperger syndrome. It wouldappear that criminality is more common at follow-up in persons with DAMP than in those with

Asperger syndrome. Gillberg (1995) found that abouthalf of adults with DAMP had significant andpersistent problems that included criminal offences.

Multidimensionally impaired disorder

Criteria for multidimensionally impaired disorder(MDI; Kumra et al, 1998) include a poor ability todistinguish fantasy from reality, impairment ininterpersonal skills and multiple deficits inprocessing information. Fitzgerald (1998) hasargued that MDI should be categorised with autismor Asperger syndrome because of the overlappingsymptomatology. Kumra et al (1998)consider MDI

an atypical variant of childhood-onset schizo-phrenia, as they share a similar pattern of cyto-genetic abnormalities, neuropsychological deficits,structural brain abnormalities, smooth-pursuit eye-tracking abnormalities, premorbid history andelevated rates of schizophrenia spectrum disorderin first-degree relatives. The nosological status ofMDI is uncertain, but we feel that the clinical diag-nosis of Asperger syndrome offers far greater oppor-tunities to engage with appropriate educational,psychological and psychiatric services (Fitzgerald,1998).

Multiple complex developmentaldisorder

The defining characteristics of multiple complexdevelopmental disorder (MCDD; Cohen et al, 1987)are shown in Box 5. Thought disorder and affectivedysregulation are more characteristic of MCDDsubjects, whereas problems in social interaction,communication and behavioural adjustment aremore typical of subjects with autistic disorder. Asthe core features can also occur in Aspergersyndrome its nosological status is uncertain.

Cerebellar affective syndrome

Cerebellar affective syndrome (Schmahmann &Sherman, 1998) presents with impairment ofexecutive functions such as planning, set shifting,abstract reasoning and working memory. It alsoincludes difficulties with spatial cognition,including visuo-spatial organisation with disinhib-ited or inappropriate behaviour. It differs fromAsperger syndrome in that it is a late-onset

condition. The persons so far studied with thiscondition range in age from 23 to 74 years. Theypresented with post-infectious cerebellitis, cerebellartumours and strokes. Differential diagnosis is easilymade on history-taking. This is a differentialdiagnosis that should be considered in olderpatients.

Dyslogia

The syndrome of dyslogia was described byJordan (1972) as the inability to apply logic andcommon sense in decision-making. Individualswith this difficulty make decisions based on partialfacts and have difficulty in integrating data intoa working whole. They have social difficultiessimilar to those of individuals with Aspergersyndrome, and dyslogia may simply describe thesame population.

Developmental learning disability of the righthemisphere (socialemotional learning disorder)

This disorder (Denckla et al, 1983) could be seen asthe product of a lack of communication betweenneurologists and psychiatrists since there is suchan overlap between this condition and Aspergersyndrome. Children with the condition havedifficulty understanding social and emotionalinformation.

Non-verbal learning disability

Non-verbal learning disability (Myklebust, 1975) ischaracterised by deficits in perception, coordination,socialisation, non-verbal problem-solving andunderstanding of humour, but well-developed rotememory. As many people with Asperger syndromehave this disability, a primary diagnosis of Aspergersyndrome is often preferred and is certainly the mostclinically useful. This is an example of excessivediagnostic splitting, although non-verbal learningdisability can occur with other disorders.

Box 5 Multiple complex developmentaldisorder (Cohen et al, 1987)

Defining characteristicsAffective regulation problemsImpaired capacity for relating

Impaired cognitive processing in childrenDisorganisation precipitated by changes inroutine

Impairment in empathyComorbid anxiety or depression


9/10


Discussion

Asperger syndrome can be misdiagnosed as a varietyof conditions (Box 6) requiring contradictory treat-ments and having a range of outcomes. Misdiag-

nosis as schizophrenia leads to the prescribing ofneuroleptics and an unnecessary risk of tardivedyskinesia; misdiagnosis as ADHD to the prescrip-tion of psychostimulants (e.g. methylphenidate),which can cause deterioration in behaviour in thispopulation. The condition may also be at the root oftreatment-resistant mental illness in adult psy-chiatry. Diagnostic confusion increases individualand family burden and causes families to seekunhelpful therapies or join the wrong supportgroups. Neuropsychiatric disorders may sharesimilar symptoms, for example autistic behaviourin schizophrenia or hyperactivity in ADHD. Theproblems this poses clinicians are compounded bypartial diagnostic assessments or the use of outdateddiagnostic categorisations (e.g. putting all autistic-type behaviours into a psychotic category or beingunaware of the existence of Asperger syndrome,which is not included in ICD9 or DSMIII).

Clearly, the differentiation of Asperger disorderfrom other conditions is complex because of the manypossibilities for misdiagnosis. The key to correct diag-nosis is a precise early developmental history, witha systematic discussion of all the criteria set out forAsperger syndrome (Wing, 1981; Gillberg, 1991) orAsperger disorder (American Psychiatric Associ-ation, 1994). Assessment instruments such as the

ADIR may be useful in establishing diagnosis. Amulti-disciplinary team approach is critical, anddiagnosis from a solely neurological, speech andlanguage or educational point of view must cease iffamilies are to be spared confused partial diagnoses.Although higher-functioning autistic spectrum disor-ders and Asperger syndrome may describe the samepopulation, the latter term remains useful. As appliedto higher-functioning children it is more acceptableto parents and ensures appropriate service provisionfor a group who, despite relatively normal cognitiveability, may have comprehensive difficulties.

References

American Psychiatric Association (1994) Diagnostic andStatistical Manual of Mental Disorders (4th edn) (DSMIV).Washington DC: APA.

(2000) Diagnostic and Statistical Manual of Mental Disorders(4th edn, text revision) (DSMIVTR). Washington DC: APA.

Asperger, H. (1944) Die Autistischen Psychopathen imKindesalter. Archives fr Psychiatrie und Nervenkrankheiten,117 , 76136. Trans. (1991) in Au ti sm an d As pe rger

Syndrome (ed. U. Frith), pp. 3792. Cambridge: CambridgeUniversity Press.

Baird, G., Charman, T., Baron-Cohen, S., et al (2000) Ascreening instrument for autism at 18 months of age: a 6-year follow-up study. Journa l of the Ameri can Academy ofChild and Adolescent Psychiatry, 39, 694702.

Baron-Cohen, S. (1989) Do autistic children have obsessionsand compulsions? British Journal of Clinical Psychology, 28,19 3200.

, Cox A., Baird G., et al (1996) Psychological markers inthe detection of autism in infancy in a large population.British Journal of Psychiatry , 168, 158163.

Bleuler, E. (1911) Dementia Praecox or the Group ofSchizophrenias . Trans. (1950)by G. Zinkin. New York:International University Press.

Cohen, D., Paul, R. & Volkmar, F. (1987) Issues inclassification of pervasive developmental disorders andassociated conditions. In Handbook of Autism and PervasiveDevelopmental Disorders (eds D. J. Cohen, A. M. Donnellan& R. Paul), pp. 540. New York: John Wiley & Sons.

Denckla M. B.(1983) The neuropsychology of social-emotionallearning disabilities. Archives of Neurology, 40, 461462.

Ehlers, S. & Gillberg, C. (1993) The epidemiology of Aspergersyndrome. A total population study. Jour na l of Chil dPsychology and Psychiatry, 34 , 13271350.

, & Wing, L. (1999) A screening questionnaire forAsperger syndrome and other high functioning autismspectrum disorders in school age children.Journal of Autismand Developmental Disorders, 29, 439484.

Erlenmeyer-Kimling, L., Rock, D., Roberts, S. A., et al (2000)Attention, memory, and motor skills as childhood predictorsof schizophrenia-related psychoses: the New York High-Risk Project. American Journal of Psychiatry, 157, 14161422.

Box 6 Differential diagnosis of Aspergersyndrome

Other pervasive developmental disorders:AutismPervasive developmental disorder not other-

wise specifiedChildhood disintegrative disorderRett disorder

Schizophrenia spectrum disorders:SchizophreniaSchizotypal disorderSchizoid personality disorder

Adult attention-deficit hyperactivity disorder

Obsessivecompulsive disorder

Depression

Other diagnostic categories:Semantic pragmatic disorder

Deficits in attention, motor control andperception

Multidimensionally impaired disorderMultiple complex developmental disorderCerebellar affective syndromeDevelopmental learning disability of the right

hemisphere (socialemotional learningdisorder

Non-verbal learning disability


10/10


Fitzgerald, M. (1998) Multidimensionally impaired disorder.Jou rnal of the American Academy of Chi ld and Ado lescentPsychiatry, 37 , 11251126.

Gillberg, C. (1985) Clinical Child Neuropsychiatry. Cambridge:Cambridge University Press.

(1989) Asperger syndrome in 23 Swedish children.Developmental Medicine and Child Neurology, 31, 520531.

(1991) Clinical and neurobiological aspects of Asperger ssyndrome in six families studied. In Autism and AspergersSyndrome (ed. U. Frith), pp. 122146. Cambridge:Cambridge University Press.

& Billstedt, E. (2000) Autism and Asperger syndrome:coexistence with other clinical disorders. Acta Psychiatr iaScandinavica, 102 , 321330.

, Rasmussen, T., Carlstrom, G., et al (1982) Perceptual,motor and attentional deficits in 6 year old children.Epidemiological aspects. Journal of Child Psychology andPsychiatry, 23 , 131144.

& Ehlers, S. (1998) High functioning people with autismand Asperger s syndrome. In Aspergers Syndrome or HighFunctioning Autism (eds E. Schoplar, G. Mesihov & L. J.Kunce), pp. 77100. New York, NY: Planum.

Howlin, P. (1998) Practitioner review: psychological andeducational treatments for autism. Jo ur na l of Ch il dPsychology and Psychiatry, 39, 307322.

(2000) Assessment instruments for Asperger Syndrome.Child Psychology and Psychiatry Review, 5, 120129.

Jordan, D. R. (1972) Dyslexia in the Classroom. Columbus,

OH: Merril.Kraepelin, E. (1919) Dementia Praecox and Paraphrenia. In

Textbook of Psychiatry (8th edn), pp. 176177. Edinburgh:E. S. Livingstone.

Kumra, S., Jacobsen, L. K., Lenane M., et al (1998)Multidimensionally impaired disorder: is it a variant ofvery early-onset schizophrenia? Jour nal of the Amer ican

Academy of Child and Adolescent Psychia try, 37, 9199.Lord, C., Rutter, M. L. & Le Couteur, A. (1994) Autism

Diagnostic Interview Revised: a revised version of adiagnostic interview for caregivers of individuals withpossible pervasive developmental disorders. Journal of

Auti sm and Developmental Disorders, 24, 659685., , Dilavore, P. C., et al (1999) Au ti sm Diag nost ic

Observational Scale (WPS edn). Los Angeles, CA: WesternPsychological Services.

Myklebust, H. R. (1975) Non-verbal learning disabilities:Assessment and intervention. In Progress in Learning Disabilities

(ed. H. R. Myklebust). New York: Grune and Stratton.Rapin, I. & Allen, D. (1983) Developmental language

disorders: nosological considerations. In Neuropsychologyof Language, Reading, and Spelling (ed. U. Kirk). New York:Academic Press.

Ramsey, J. M., Andresen, N. C. & Rapoport J. L. (1986)Thought, language, communication and affectiveflattening in autistic adults. Archives of General Psychiatry,43 , 741777.

Schmahmann, J. D. & Sherman, J. C. (1998) The cerebellarcognitive affective syndrome. Brain, 121, 561579.

Szatmari, P. (1998) Differential diagnosis of Asperger sdisorder. In As perger s Syndrome or High Functioning

Autism? (eds E. Schopler, G. Mesibov & L. Kunce), p. 71.New York: Plenum.

Wing L. (1981) Asperger s syndrome: A clinical account.Psychological Medicine, 11, 115130.

& Gould, J. (1979) Severe impairments of social

interaction and associated abnormalities in children:epidemiology and classification. Jou rna l of Aut ism andDevelopmental Disorders, 9, 1129.

Wolff, S. (1998) Schizoid personality in childhood: the linkswith Asperger s syndrome, schizophrenia spectrumdisorders, and elective mutism. In Aspergers Syndrome or

High Functi oning Autism (eds E. Schopler, G. Mesibov &L. Kunce), pp. 123145. New York: Plenum.

World Health Organization (1992) The ICD10 Classificationof Diseases Clinical Descriptions and Diagnostic Guidelines .Geneva: WHO.

(1993) The ICD10 classification of Mental and BehaviouralDiosrders: Diagnsotic Criteria for Research. Geneva: WHO.

Multiple choice questions

1. In Asperger syndrome:a onset is after age 3 years

b non-verbal deficits are more common thanverbal

c motor coordination problems are commond relatives of affected children have increased

risk of schizophreniae speech acquisition is normal.

2. DSMIV criteria for Asperger disorder include:a lack of enjoyment in activities

b motor mannerismsc failure to relate to peersd inability to maintain routinese lack of social imitative play (appropriate to

developmental level).

3. About autism spectrum disorders in adolescence:a they may be misdiagnosed as schizophrenia

b features include inattention and overactivityc symptoms become more prominent with aged repetitive activities are resistede developmental history is not necessary to make

the diagnosis.

4. Asperger syndrome:a can be clearly differentiated from the autism

spectrum disordersb is as sociat ed wi th de la yed cognit ive

development

c is more prevalent than classic autismd has a major genetic componente resolves in adulthood.

5. Patients with Asperger disorder:a may meet diagnostic criteria for semantic

pragmatic disorderb are at increased risk of schizophreniac are more likely to be boys than girlsd can be diagnosed with ADHD in DSMIVe have an increased risk of mood disorder.

MCQ answers

1 2 3 4 5a F a F a T a F a Tb F b T b T b F b Fc T c T c F c T c Td F d F d F d T d Fe F e F e F e F e T

Documents

Diagnosis and Differential Diagnosis of Asperger Syndrome