Autistic spectrum disorder

The term autistic or pervasive development disorders denotes a spectrum of clinically similar disorders with variable severity, all characterized by a triad of  impaired social interaction, impaired verbal & nonverbal communication, and rigid, repetitive or obsessive behavior.

While childhood Autistic spectrum disorder (Infantile autism) is the prototype of this spectrum, Asperger’s disorder is more common but milder variant, with impaired social interaction and rigid, stereotype behavior but without language involvement.

Incidence of this disorder

Although the reported incidence of childhood autism in developed countries is — 5/10,000 children (1/1000 for Asperger disorder), under-diagnosis is common in developing countries. In India, the incidence appears to be increasing due to rising awareness. Autism is 3-4 times more common in males and high socioeconomic strata, probably due to increased chances of detection.

Etiology

The exact etiology is hitherto unknown, but autistic spectrum disorders are frequently associated with family history, chromosomal disorders like fragile X chromosome, genetic disorders like Phenylketonuria, intrauterine infections like rubella, congenital brain malformations like hydrocephalus, and postnatal encephalitis, meningitis and infantile spasms. Familial or Genetic predisposition is supported by — 80% and 20% concordance rate in monozygotic and dizygotic twins.

autistic spectrum disorder

Clinical features

Autistic children are often considered as “good babies” in infancy, as they do not demand attention. Delayed development of speech is usually the initial parental concern in these cases, with gradual recognition of typical features, as follows —

a) Impaired social interaction: These children do not show any interest in their parents and do not make friends. They are withdrawn, spends hours in solitary play, often preoccupied with trivial objects e.g. buttons or parts of their own body.

b) Impaired communication: These children lack in both – verbal as well as non-verbal communication skills. Even after development of speech, they are unable to sustain a conversation and have other abnormalities e.g. echolalia, pronominal reversal, nonsense rhyming etc. Cognitive development for information processing & temporal sequencing is mainly affected.

c) Stereotype behaviors i.e. inordinate desire for sameness with rigid interests and repetitive or obsessive activities. These children play for many hours with one object, alone, & don’t want to be disturbed.

d) Associated behavioral problems e.g. hyperactivity, short attention span, impulsivity, aggressiveness, temper tantrums are common. Most of them have odd responses to sensory stimuli e.g. higher pain threshold or over-sensitivity to touch, sound, light odors etc.

Intelligence in autistic spectrum disorder is almost always affected with average IQ of <70 in most cases.

Diagnosis

It is is essentially clinical, based on the DSM IV criteria. However the assessment of its severity and presence of co-existing abnormalities require — a) comprehensive assessment of hearing, speech and language, b) periodic evaluation for cognitive functions (IQ), social adjustment, verbal performance and non-verbal communication, c) psychiatric evaluation for secondary behavior disorders.

DID of autistic spectrum disorder include other cause of inattentiveness and poor communication e.g. deafness, mental handicap, developmental language disorder, childhood schizophrenia, Rett syndrome and Attention- deficit hyperactivity disorder.

Rett syndrome is a rare, X-linked disorder, almost exclusively seen in females (lethal in males), * Of these six features from category A, at least two should be from sub- category I and one each from 2 and 3.

Characterized by normal development till 6-12 months, followed by regression of motor and linguistic milestones, secondary microcephaly, and stereotype hand movements e.g. hand-wringing.

Management

Management of Autistic children aims to achieve as much functional independence as possible and requires a mulch-disciplinary approach. Important components include —

a) Pharmacotherapy, though not curative, is a valuable tool to control certain symptoms and improve leaming process as well as social adaptation. The choice of drug depends on predominant symptoms and includes

a) dopamine antagonists e.g. halperidol and neuroleptics e.g. risperidone to control aggressive and self-injurious behavior

b) fenfiuramine and opiate antagonists e.g. naltrexone to control stereotype behavior and improve social interaction

c) methyphenidate to control hyperactivity

d) tricyclic antidepressants e.g. clomipramine to control obsessive compulsive behavior; and

e) anticonvulsants to treat seizures. Other drugs like serotonin re-uptake inhibitors e.g. Fluroxamine and re-combinant secretin – a peptide hormone etc., with claims to improve social interaction, are of unproven value.

f) Play therapy, language therapy and behavior therapy using operant conditioning, have shown promising results in some cases.

g) Psychotherapy and psychoanalysis, in children with at least some communication.

Diagnostic criteria for Autistic spectrum disorder (DSM IV )

A. Presence of at least 6 of following features:

1. Qualitative impairment in social interaction (at least 2)

— Poor non-verbal behavior (eye contact, expressions)

— Fails to develop age-appropriate peer-relationship

— Lack of desire to share interests with other people

— Lack of emotional & social reciprocity

2. Qualitative impairment in communication (at least 1)

— Delayed speech/poor non-verbal communication

— Inability to initiate or sustain conversation

— Stereotype use of words absent personal pronouns

— Lack of age-appropriate social imitative play

3. Restricted, stereotype behavior & activities (at least 1)

— Rigid interests with abnormal intensity

— Adherence to non-productive routines or rituals

— Stereotype, repetitive motor movements

— Preoccupation with parts of objects or body

B. Delay in following areas by 3 years of age (at least 1)

— Social interaction

— Language for social communication

— Symbolic or imaginative play

d) Family therapy is required for parents to understand the problem and cope with the stress of the Autistic spectrum disorder. Currently, many support groups involving affected parents, health professionals and voluntary organizations are working in India for this purpose. Individualized planning for education and imparting practical skills should be made.

Prognosis

The children with this disorder, reared in a positive environment, show some improvement during early school years. However symptoms tend to re-aggravate during adolescence with deterioration in behavioral and cognitive skills, additional psychiatric problems and appearance of epilepsy, especially in girls. As sexual drive increases, they may indulge in embarrassing behaviors.

Absence of communicative speech till 5-6 years of age indicates poor prognosis. Relationship of Autistic spectrum disorder with later development of schizophrenia is likely, but not established.

Check out the below video on Autistic spectrum disorder from NHS Choices -