Autism comes under the group of pervasive developmental disorders of children. These disorders are characterized by qualitative abnormalities in reciprocal social interactions and in patterns of communication along with restricted, stereotyped, repetitive activities.
Childhood autism was first described by Leo Kanner in 1943. He described 11 children who were “unable to relate” in usual ways to the people and considered it as autistic disturbances of affective contact. The term “autos” means self, and these children have a tendency to morbid self absorption.
Socioemotional reciprocity is the essence of human relationship and autism is a prototype disorder of sociocognitive development.
Prevalence of Autism
Recent studies have shown a prevalence rate 10 – 20 per 10000 children. The sex ratio of boys:girls is 4:1.
Etiology: Biological Factors
Abnormalities have been found in “social brain” – orbito-frontal and medial frontal cortex, superior temporal gyrus and limbic system – especially, reduced amygdala volume.
Relative increase in brain volume has been noted in MRI studies possibly due to failure of synaptic pruning. There is also reduced neuronal size in the hippocampus, amygdala, anterior cingulate cortex and mamillary bodies.
Diagnostic criteria
1. Qualitative impairment in reciprocal social interaction, characterised by:
Failure to develop appropriate peer relationships.
Marked impairment in multiple nonverbal behavior to regulate social interaction.
Lack of social or emotional reciprocity.
Lack of spontaneous seeking to share enjoyment, interests, and achievements with other people.
2. Qualitative impairment in communication as follows:
Delay in, or total lack of, the development of spoken language.
Impairment in the ability to initiate and sustain conversation with others.
Stereotyped or repetitive use of language.
Lack of varied, spontaneous play or social imitation of play.
3. Restricted repetitive and stereotyped behavior:
Stereotyped and repetitive motor mannerisms.
Persistent preoccupation with objects or preoccupation with one interest that is either abnormal in intensity or focus.
Inflexible adherence to specific, non-functional rituals or routines.
Along with the above primary symptoms of autism, these children have also have cognitive delays, motor delays and sensory difficulties.
Abnormalities of motor behaviour include hand flapping, waving in front of the eyes, tip toe walking and echopraxia. Echopraxia is the involuntary repetition or imitation of the observed movements of another individual.
Abnormal reponses to sensory stimuli include hyperacusis, tactile defensiveness – extreme sensitivity to touch or insensitivity to pain – may not cry after a severe injury.
Fascination to certain sensory stimuli such as spinning objects is common in autistic children. Some enjoy vestibular sensations such as twirling without becoming dizzy.
Savant skills in autism
10% of people on the autistic spectrum have savant skills. They have high, sometimes prodigious performance on a specific skill in the presence of mild or moderate mental retardation.
e. g. Memorizing lists, calender calculation, drawing skill, musical skill.
Atypical autism
Atypical autism is a type of pervasive developmental disorder that differs from childhood autism either in age of onset or in failing to fulfill all diagnostic criteria. Atypical autism manifests after the age 3 years or there are impairments in communication and stereotyped behaviour, but emotional response to caregivers is not affected.
Differential diagnosis of autism
Two other pervasive developmental disorders which come in the differential diagnosis include:
1. Asperger syndrome
Asperger syndrome was described by Asperger in 1944. It is characterized by the same kind of impairment of social activities and stereotyped features of behaviour as is described in autistic children.
There is no delay of speech and cognitive development. The condition occurs predominantly in boys (8:1).
2. Rett’s syndrome
Rett’s syndrome has been described only in girls. Normal early development is followed by partial or complete loss of speech and of skills in locomotion and use of hands, together with deceleration in head growth. Onset of Rett’s syndrome is between 7 and 24 months of age. Loss of purposive hand movements, hand-wringing stereotypies, and hyperventilation are the importan features of Rett’s syndrome. Motor functioning is more affected in middle childhood and muscles are hypotonic. Kyphoscoliosis and spasticity in the lower limbs occurs in majority of cases.
Other differential diagnoses of autism include selective mutism, receptive language disorders, expressive language disorders, mental retardation and obsessive compulsive disorder.
Assessment of autism
Developmental history is essential. Assessment of intelligence, self help skills and pre academic skills helps in planning the remedial training programs. Structured interviews like Autism Diagnostic Interview (ADI) and unstructured behavioral scales like Childhood Autism Rating Scale (CARS) and structured behavioral observation scales like Autism Diagnostic Observation Scale (ADOS)
help in arriving at a correct diagnosis.
Behavioural Analysis
Behavioural analysis should be done using ABC chart (antecedent, behaviour, consequence). Determine child’s current developmental level, strengths and weaknesses, likes and dislikes.
Treatment of autism
Early and intensive intervention is essential for successful management of autism. Medication is needed for children with aggressive behaviour. Behaviour modification programmes and social skills training and speech stimulation programs helps in improving the socioemotional reciprocity as well as communication skills of these children and helps in alleviating the stereotyped behaviours.
Conclusion
Identifying children with autism and initiating intensive, early ntervention during the preschool years, results in improved outcomes.
