autistic spectrum disorder pervasive developmental disorders

AUTISTIC SPECTRUM DISORDERPERVASIVE DEVELOPMENTAL DISORDERS

PAEDIATRICIAN’S PERSPECTIVEHO LAI YUN

AUTISTIC SPECTRUM DISORDER (ASD) PERVASIVE DEVELOPMENTAL DISORDERS

Autistic Spectrum Disorder / Pervasive Developmental Disorders (PDDs) are a group of brain-based neuro-behavioural disorders of diverse aetiologies, and may co-exist with other developmental disabilities such as mental retardation, seizure disorders, attention-deficit hyperactivity disorder.

These disorders are usually regarded as life-long. Recent evidence suggests that early and intensive behavioural and educational interventions can make a significant positive impact on long-term outcomes.

PERVASIVE DEVELOPMENTAL DISORDERS THE TRIAD OF IMPAIRMENTS

Impairments in reciprocal social interaction skills.

Impairments in communication.

Presence of stereotyped patterns of behaviour and

markedly restricted repertoire of activities & interests.

Volkmar and Rutter 1995

THE SPECTRUM OF PERVASIVE DEVELOPMENTAL DISORDERS

American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders,

Fourth Edition Text Revision (DSM-IV-TR) 2000.

Autistic Disorder (Classic Autism)

Asperger’s Syndrome

Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS)

Childhood Disintegrative Disorder (Heller’s Syndrome)

Rett’s Syndrome

PREVALENCE Current impression : incidence of ASD is rising, due to wider

diagnostic criteria, greater awareness, or a genuine change in incidence

Older studies estimated prevalence of autism to be 4 to 5 in 10,000 children.

The majority of studies conducted through 1998 showed prevalence of 1 in 1,000 children and the broader ASD to be 1 in 500 children !

Recurrence rates for isolated ASD in subsequent offspring range from 3% to 7%, representing a recurrence risk of about 50 times the general population.

Isolated ASD : boy-to-girl ratio about 4:1.

AUTISTIC DISORDER DIAGNOSTIC CRITERIA (DSM-IV-TR 2000)

A. A total of SIX (or more) items from the following groups:

Qualitative impairments in Social Interaction (4 items)

Qualitative impairments in Communication (4 items)

Restricted, repetitive, and stereotyped patterns of behaviour,

interests, and activities (4 items)

B. Delays or abnormal functioning in at least one of the following

areas with onset prior to age 3 years :

Social interaction

Language as used in social communication

Symbolic or imaginative play

AUTISTIC DISORDER DIAGNOSTIC CRITERIA

Qualitative impairments in Social Interaction, as manifested by at

least TWO of the following criteria :

Marked impairment in the use of multiple nonverbal behaviours

such as eye-to-eye gaze, facial expression, body postures, and

gestures to regulate social interaction

Failure to develop peer relationships appropriate to developmental

level

A lack of spontaneous seeking to share enjoyment, interests, or

achievements through joint involvement with other people, (e.g.,

by a lack of showing, bringing, or pointing out objects of interest)

Lack of social or emotional reciprocity

IMPAIRMENTS IN RECIPROCAL SOCIAL INTERACTION

Three main types of social interaction impairments (Wing 1988) Impaired social recognition : lack of empathy (an interest in the

feelings & thoughts of others); lack of eye contact; aloofness and indifference to other people except for one or more caregivers.

Impaired social communication : absence of pleasure in the exchange of smiles and (i.e.body language); lack of desire to communicate with others, at most limited to simple expression of needs.

Impaired social imagination and understanding : inability to imitate others (waving bye-bye), to engage in pretend play (copy mother’s domestic activities ), or to imagine other’s thoughts and feelings (not copying mothers’ facial expressions).

Others : not seeking comfort when hurt, no interest in forming friendships. They do not know how to play!


Qualitative impairments in Communication, as manifested by

at least ONE of the following criteria :

Delay in, or total lack of, the development of spoken language

that is not accompanied by an attempt to compensate through

alternative modes of communication such as gesture or mime.

In individuals with adequate speech, marked impairment in the

ability to initiate or sustain a conversation with others.

Stereotyped and repetitive use of language or idiosyncratic

language.

Lack of varied, spontaneous make-believe play or social

imitative play appropriate to developmental level.

COMMUNICATION IMPAIRMENTS in AUTISTIC DISORDER

Both expressive and receptive language are delayed and deviant.

Cooing and babbling may be lost by six months. Speech may develop late or not at all. About half will remain mute and may be unable to use gestures or signs to communicate.

When spoken language does develop, the first word is often spoken at 2-3 years old; however, speech pragmatics is impaired.


Speech is idiosyncratic and echolalic, rather than spontaneous or

creative.

Echolalia may be immediate (e.g., repeating the last part of a

question) or delayed (repeating stock phrases, songs or long

commercial jingles). Essentially parroting things heard.

Echolalia may improve with age in higher functioning autistics,

but the basic problems with pragmatics remain. It is the social

use of language that is impaired, not the more formal aspects

of vocabulary, grammar, and articulation.


Confusion of personal pronouns (using you to refer to oneself)

and verbal perseveration (dwelling on a specific subject).

Abnormalities of prosody : high-pitched voices, unusual speech

rhythm and intonation, making the speech sound sing-song,

monotonous, and robotic.

Expressive language is therefore used in a stereotyped and rote

fashion, exhibiting relatively better memorization skills but often

communicating very little meaning.

Receptive language is impaired and they may appear deaf.

They learn better with visual, rather than with auditory, cues.


Restricted, repetitive, and stereotyped patterns of behaviour, interests, and activities, as manifested by at least ONE of the following criteria :

Encompassing preoccupation with one or more stereotyped, restricted, and repetitive patterns of interest that is abnormal either in intensity or focus.

Apparently inflexible adherence to specific, non-functional routines or rituals.

Stereotyped and repetitive motor mannerisms (e.g., hand or finger flapping or twisting, complex whole-body movements)

Persistent preoccupation with parts of objects.

BEHAVIOURAL ABNORMALITIES in AUTISTIC DISORDER

Autistics have a desire for sameness and resist change. This is marked by restricted, perseverative, and stereotyped patterns of behaviours, interests, activities and lack of representational or pretend play

Obsessive rituals and strict adherence to routines : e.g., rigid insistence on eating at the same time each day or eating a restricted menu of foods, sitting at the same position at the table, placing objects in a particular location, or touching every door knob one passes.

Intense attachment to unusual objects: e.g., a piece of string rather than a cuddly teddy bear.


They may not use toys in their intended manner but focus on a part of a toy, like the wheels which they may spin endlessly. A common form of play is to line objects up in row.

Shining surfaces, rotating fans, and people’s hair or beards may fascinate the young autistics. Toys lose novelty only after very long time. A single movie may be watched many times without child becoming bored.

Older autistics may be preoccupied with bus / train schedules, calendars, or particular patterns of numerical relationships.


Autistic children may become upset and have temper

tantrums if the rituals & preoccupations are interrupted,

trivial departures from daily routines or changes in

environment. ( e.g., when a furniture is moved from usual position, insisting on

exactly the same route be followed when shopping ).

Stereotyped movements & self-stimulating behaviours : rocking, hand waving, arm flapping, spinning, toe walking, head

bagging and even self-injurious behaviours.

ASPERGER SYNDROME

Asperger syndrome is characterised by poor peer relationships, lack of empathy, and a tendency to over-focus on certain topics.

Asperger syndrome is associated with a typical IQ and relatively typical language skills.

Some aspects of cognitive development may appear advanced, e.g., may recognise letters by three and brand-name logos or car models by four. May have hyperlexia, able to read before five but comprehend little. Frequently recognised later in childhood.

ASPERGER SYNDROME

Spoken language may be unusually pedantic and formal, tends to centre on idiosyncratic interests; and the nonverbal aspects of communication: eye contact and body position may be abnormal.

Older children exhibit unusual activities and interests in maps, sports statistics, bus schedules, etc; some preoccupations may be adaptive and lead to future careers like computing.

Delayed motor milestones and clumsiness.

ASPERGER SYNDROME DIAGNOSTIC CRITERIA

1. Gross and sustained impairment in social interaction as manifested by at least TWO of the following:

Marked impairment in the use of multiple non-verbal behaviours such as eye-to-eye gaze, facial expression, body postures, & gestures to regulate social interaction

Failure to develop peer relationships appropriate to developmental level

Lack of spontaneous seeking to share enjoyment through joint involvement with others.

A lack of social or emotional reciprocity.

ASPERGER SYNDROME DIAGNOSTIC CRITERIA

2. Restricted, repetitive, and stereotyped patterns of behaviour, interests, and activities.

3. Lack of any clinically significant delays in language : may be hyperlexic, able to read before 5, but comprehend little.

4. Lack of any clinically significantly delay in cognitive developments as manifested by the development of age-appropriate self-help skills, adaptive behaviour, and curiosity about the environment; some aspects may appear advanced.

5. Not better accounted for by another specific pervasive development disorders.

PERVASIVE DEVELOPMENTAL DISORDER NOT OTHERWISE SPECIFIED (PDD-NOS)

PDD-NOS is a term reserved for those individuals with abnormal social and communication skills and stereotyped behaviours that are

of relatively brief duration, of later age at onset, Of insufficient severity to meet the criteria for autistic

disorder or a specific PDD diagnosis, atypical or sub-threshold symptomatology, and

exclusion of schizophrenia, schizoid and avoidant personality disorders.

PERVASIVE DEVELOPMENTAL DISORDER NOT OTHERWISE SPECIFIED (PDD-NOS)

In practice, PDDNOS is used to described individuals with mild autistic features, which may later be revised to Autistic Disorder if additional symptoms appear later and the child meets the full criteria.

Differentiation between PDDNOS & language-based

learning disability with poor social adjustment is not

easy, and the diagnosis that appears to lead to the

most appropriate educational setting is the one that

should be given

PERVASIVE DEVELOPMENTAL DISORDERS

Characteristics Autistic Asperger PDD-NOS Rett CDD

Social Impairment + + + + +

Language/Communication + + + +

Impairment

Restricted/Repetitive + + + + +

Interests & Activities

Phase of Normal Development + +

Loss of Skills in Several Areas + +

Stereotyped Hand Movements +

Onset before 36 months +

Average Intelligence +

ASSOCIATED IMPAIRMENTS

Mental Retardation

Seizure Disorders

Attention Deficit Hyperactivity Disorder

Psychiatric Disorders

Behaviour Disorders

Sensorimotor Symptoms

EARLY IDENTIFICATON OF AUTISM

There is strong evidence that the diagnosis can be made reliably between 18 -36 months of age:

Systematic review of early videotapes demonstrates prelinguistic communication abnormalities in infancy.

Parent questionnaires & other structured screening instruments often retrospectively reveal impairments in pretend play, proto-declarative pointing, joint-attention, social interest, and social play as early as 18 months.

PROBLEMS IN EARLY IDENTIFICATION

Wait-and-see or reassuring attitude towards parents’ concern over child’s delayed language acquisition, especially boys.

Problems in identifying developmental delays in socialization and other non-verbal communication behaviours.

The nature of impairments are subtle, they often represent the absence of normative behaviours (not imitating, not gesturing) rather than the presence of noticeably unusual behaviours ( peculiar use of language).

PROBLEMS IN EARLY IDENTIFICATION

Differentiation between ASD and mental retardation may be difficult : given a child’s developmental level, there may not be an opportunity to manifest the behaviours needed for diagnosis.

Differentiating milder ASD from developmental disability may be difficult if the child has not been involved in some preschool programme to evaluate their response to structured environments and exposure to other children.

DIAGNOSTIC ASSESSMENT INSTRUMENTS FOR AUTISM

Observational Scales Autism Behaviour Checklist (ABC) Autism Diagnostic Observation Schedule (ADOS) Behaviour Rating Instrument for Autistic and Atypical

Children (BRIAAC) Childhood Autism Rating Scale (CARS) Diagnostic Checklist for Behaviour-Disturbed Children

(Form E2) Ritvo-Freeman Real Life Rating Scale (RLRS) Denver Developmental Screening Test (DDST) is NOT

sensitive and specific for ASD.

DIAGNOSTIC ASSESSMENT INSTRUMENTS FOR AUTISM

Parental Interviews Checklist for Autism in Toddlers (CHAT) :

Screening tool for 18-month-old in primary care setting.

Children with global delays are likely to also fail CHAT.

Pervasive Developmental Disorder Screening Test

(PDDST): a parent-completed survey from birth to 3 years.

Autism Diagnostic Interview - Revised (ADI-R)

Diagnostic Interview for Social and Communication

Disorders (DISCO)

CHECKLIST for AUTISM IN TODDLERS For Children 18 months and older (CHAT)

Section A: History: Ask parents… :1. Does your child enjoy being swung, bounced on your knees, etc?

2. Does your child take an interest in other children?

3. Does your child like climbing on things, such as stairs?

4. Does your child enjoy playing peek-a-boo/hide-and –seek?

5. Does your child ever PRETEND, e.g., to make a cup of tea using a toy cup and teapot/pitcher or pretend other things?

6. Does your child ever use his/her index finger to point, to ASK for something?

7. Does your child ever use his/her index finger to point to indicate interest, that is to get you to look at it? (protodeclarative pointing)

8. Can your child play properly with small toys (eg., cars or bricks)?

9. Does your child ever bring objects over to SHOW you something?


Section B: Observation:

1. During the appointment, has he made eye contact with you ?

2. Get the child’s attention, then point across the room at an interesting object and say, “Oh look! There is a (name object).” Watch the child’s face. Does the child look across to see what you are pointing at ?

3. Get the child’s attention, then give the child a miniature toy cup and teapot and say, “Can you make a cup of tea?” Does the child pretend to pour the tea, drink it, and so forth ? (May use other objects for pretend play)

4. Ask the child, “ Where’s the light?” or say, “Show me the light.” Does the child POINT with his/her finger at the light?

5. Can the child build a tower of bricks?


Severe risk for Autism : Fails A5, A7, B2, B3, & B4.

Mild risk for Autism : Fails only A7, B4

Risk for different Developmental Disorder:

>3 failures on any item.

Within normal limits : < 3 failures on any item.

DIAGNOSTIC EVALUATION

Diagnosis of ASD is based on clinical rather than laboratory findings. Use of DSM-IV/autism-specific diagnostic inventories substantially increase the diagnostic reliability.

Comprehensive assessment & management planning require a specialized multidisciplinary team.

Judgement regarding the presence or absence of a constellation of symptoms is subjective and depends on the physician’s understanding of and experience with ASD.

DIAGNOSTIC EVALUATION

As diagnosis is behaviourally based, information about the child should be gathered from multiple sources and across multiple settings : interviews with parents & care providers (teachers) as well as observation of the child in structured situations (such as developmental testing ) and unstructured situations (such as play), with help of videotape recordings.

To establish the presence of the autism triad.

GOALS OF TREATMENT OF AUTISM

There is no medical cure for autism at the present time !

SIX main goals of treatment : Fostering of development Promotion of learning Reduction of rigidity and stereotypy Elimination of nonspecific maladaptive behaviours Increase independence in daily living skills Alleviation of family distress

A combination of behaviour treatment, education, speech-language therapy, pharmacotherapy, and family support.

EDUCATIONAL INTERVENTIONS

Provision of early and intensive remedial education in a highly

structured environment with a high teacher-to-student ratio.

Provision of individualized programming that is developmental

in nature and focuses on the specific deficit areas.

Immersion or placement of ASD children into community pre-

schools, using non-disabled peers as agents of change and

as models, to encourage develop skills needed for integration

in other mainstream settings (mainstreaming vs special school).

EDUCATIONAL INTERVENTIONS

Emphasis and opportunities on generalization of

skills.

Behavioural treatments and judicious use of

medications are potentially important adjuncts in

facilitating learning.

Parental involvement in educational program.

BEHAVIOUR MANAGEMENT

Behavioural problems arise from poor communication skills,

difficulty with transitions, too much sensory stimulation,

difficulty giving up an obsession, or inability to understand

concepts like sharing and cooperation.

The key principle in behaviour management is not so much

to extinguish ASD behaviour, but rather to replace it with

more appropriate social, communication, & daily living skills.

Make an inventory of the situations that precipitate difficult

behaviours and then try to prevent or avoid them if possible,

or to make it easier for the child to communicate his needs.


Providing structure and routine, not letting the child engage

excessively in obsessive activities, being gently and socially

intrusive, finding toys and activities that the child enjoys can

be effective in promoting more appropriate development.

Breaking down a learning task into logical steps & instructing

the individual through the task in a naturalistic setting. A set

of prompts is identified for each step & compliance rewarded.

By surrounding the child with the communications of others

and with the social Interactions and responses of others,

he is exposed to more developmentally appropriate

behaviours and can model them through learning.


Difficult and aggressive behaviours can be signals of

distress, the precipitating events should be identified

(e.g., physical illness).

Emphasis is on positive reinforcement, as one key

element in the disorder is the absence of motivation

to take part in social interaction.

Negative reinforcement, punishment and withdrawal

from social situations will perpetuate the difficulty.

EARLY INTERVENTION PROGRAMS

Community and Integrated Settings : TEACCH (Treatment and Education of Autistic and

Related Communication Handicapped Children ), a statewide program in North Carolina USA.

The program stresses increasing motivation to communicate by behavioural shaping of appropriate responses and generalizing them to naturalistic settings. Active parental involvement in identifying educational goals and implementing treatment strategies

EARLY INTERVENTION PROGRAMS

Specialized and Individualized Settings : Lovaas Program (1987) : an intensive ( 40 hours

per week ) and comprehensive one-to-one teaching model.

The therapy is highly structured and focused on strict behavioural management principles; parents are trained as therapists:

Too specialized and too expensive for community settings.

SPEECH-LANGUAGE THERAPY

The overall goal is to encourage the social use of language, ability to develop more developmentally appropriate communication skills, and to broaden the repertoire of communicative functions.

Emphasis is on the pragmatics of communication : the use of language to accomplish social or practical goals, rather than on articulation, grammar, vocabulary, or meaning of words.


Any form of communication is to be encouraged and rewarded.Techniques include spoken language, sign language, and communication devices ranging from simple picture cards to computerized devices that produce verbal or written output.

The child’s abnormal or unusual speech patterns may serve a function and should be assessed, a few simple strategies can be developed and be implemented by parents and teachers.


Withdrawing the child for one-on-one speech therapy should only be used as an assessment tool, as it removes the child from real-life situations that require language and compounds the difficulties with generalization of newly acquired skills.

Communication therapy should be provided in a natural setting : this is best accomplished in social interactions with toys, books, and other activities the child enjoys. Getting the child to repeat certain words does not necessarily promote spontaneous output of language.


Pairing verbal with exaggerated non-verbal cues,

as well as pictures and photos will enhance

understanding and expression.

“Facilitated Communication”

(Crossley and Biklen 1990) is still a controversial

and scientifically untested linguistic approach.

ALTERNATIVE THERAPIES Nutritional supplements:

High-dose pyridoxine and magnesium (neurotoxicity). Ascorbic acid; dimethylglycine (Russia).

Elimination diets : Gluten and milk elimination.

Immune globulin therapy. Secretin infusion. Chelation therapy :

methylmercury in some fish; thimerosal (ethylmercury) in vaccines. Hair analysis not necessary; and chelation therapy may be toxic.

ALTERNATIVE THERAPIES

Facilitated Communication : a “facilitator” providing physical support under the arm of a child to permit typing of messages on a keyboard communicator.

Auditory Integration Training : Having the child listen through earphones to sounds in which specific frequencies have been filtered out.

ACTH and prednisone : for children with autistic features who have Landau-Kleffner syndrome.

Others : piracetam, treat fungal infections, special tinted glasses.

COURSE and PROGNOSIS

Despite promising treatment advances and popularized reports of cures, the prognosis for the child with autism remains guarded.

Disturbed behaviour is often evident from age 2 to 5 years, tends to improve from 6 to 10 years, as some children start to acquire language and learn to communicate, but may re-appear in adolescents & young adults, eventually calming down in middle and later life. Problems can be diminished by appropriate care and management at any age.


Behavioural deterioration in adolescence may reflect the effects of hormonal changes, the difficulty of meeting greater demands in an increasingly complex social milieu, or even depression.

A small number of more able individuals break the law in pursuit of their special interests or because of paranoid feelings arising from social rejection.


The outcome for independence in adult life is closely linked to overall level of ability: especially verbal abilities and intelligence.

Predictions of adult intellectual functioning should be deferred until 5 or 6, as they may be inaccurate and some symptoms may resolve.

The presence of hyperlexia ( precocious ability to decode words) is favourable.

Absence of communication by 5 years old a more limited outcome.


Those with severe learning disabilities will remain

dependent all their lives, requiring total support

& supervision in living accommodation, occupation,

and leisure activities.

Those with mild learning disabilities may achieve

some degree of independence in living or working

but most likely need some support to help them

cope with pressures of daily life.


Those with average or high ability will be quite

independent as adults.

Those with adequate social skills may find a niche

that enables them to become self-supporting.They

still tend to be regarded as eccentric and as loners.

Social skills rarely improve enough to permit

successful marriage, although some do marry and

have children.


Major barriers to social function may be related to lack of opportunity and instruction as much as to intrinsic impairments.

Evidence suggests that individuals with ASD will continue acquiring new adaptive skills throughout their life span.

No published studies of longevity. Life expectancy affected by the presence of other conditions with implications for physical health, e.g., epilepsy, tuberose sclerosis..

autistic spectrum disorder pervasive developmental disorders

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