| Autism Spectrum Disorder is one
of the Pervasive Developmental Disorders (PDD), characterized by severe
impairments in communication and social skills, a restricted range of
interests and activities and stereotyped behaviours. Impairments in
communication and social interaction are not merely developmental in
nature but constitute deviations relative to the individual’s
developmental level or mental age.
The disorder was first identified in 1943
by Leo Kanner. Over the years, the following terms have been used to refer
to this disorder: "childhood schizophrenia", "early
infantile autism", "childhood autism". The cause of autism
continues to elude us. The early theories, postulating a psychogenic
aetiology, have been irrevocably refuted. We now know that autism is a
biological disorder. In the majority of cases, the trauma to the organism
occurred prenatally.
Prevalence Of Autism Spectrum Disorder
Autism Spectrum Disorder is a disorder of childhood onset, usually before 30 months of age.
However, diagnosis may not occur until later in childhood. The symptoms of
autism may be present from birth, but they may not be noticed until a
child is two or three, when language normally develops. It was
once thought that Autism occurs
approximately in 10 to 12 people per 10,000 but recent studies have found
the incidence of Autism Spectrum Disorder to be much greater.
The diagnosed incidence of Autism Spectrum Disorder and related
conditions have increased tenfold over the past few decades. It
is not known whether this is simply due to more thorough
identification or diagnosis, or to other causes such as
environmental influences. In fact, many experts feel that this
increase may be due to a combination of better diagnosis and
environmental causes. The incidence of Autism Spectrum Disorder
is now being documented at less than 1 in 200 of the population.
Autism is four times more
common in boys than it is in girls. It occurs in all races and social and
economic conditions all over the world. There are several theories, but no
conclusive answers as to the cause(s) of autism. One thing that we do know
is that autism is NOT caused by deficient parenting, which was put forth
as a theory when autism was first recognized as a distinct disability in
the 1940's.
What Are The Symptoms of Autism Spectrum
Disorder?
Symptoms may be present from birth,
but they may not be noticed until a child is two to three years old, when
one would normally expect to see the development of language. Parents may
report that the child was an unusually good and quiet baby who rarely
cried, or a very difficult baby who cried all the time, spit up
excessively and slept for only short periods. One of the most frustrating
and confusing characteristics may be the child’s inability to develop
appropriate affectionate relationships. He/she may resist being held and
cuddled, and may not seem to recognize familiar faces (or alternately may
indiscriminately display affection towards unknown individuals).
The nature of the impairment may change
over time and may vary depending on the developmental level of the
individual. People with autism comprise a heterogeneous group, differing
in the number of characteristics they display as well as in the severity
of their symptoms.
Other features frequently seen in
individuals with autism include a variety of behavioural symptoms such as
self-injurious behaviours, aggression, hyperactivity and short attention
span. They may have unusual responses to sensory stimulation, such as high
tolerance for pain, over or under-reaction to sounds, oversensitivity to
being touched, fascination by lights, shiny objects, etc. Expressions of
affect or mood are frequently abnormal. There may be an apparent absence
of emotional reaction or the reaction is inappropriate to the context.
Diagnosis of Autism Spectrum Disorder
The diagnosis of Autism Spectrum Disorder often occurs between the ages of 18 months and 30
months when parents notice an absence or a delay in speech development and
a lack of normal interest in others or a regression of early speech and
sociability. Autism is diagnosed based on a history of the child’s
development provided by those who know the child well along with
observations of the child’s behaviour. A variety of information such as
the child’s developmental history in areas such as speech,
communication, social and play interaction is required. A
multi-disciplinary team may include the family doctor, psychologist,
speech and language pathologist and an audiologist.
A diagnosis of Autism Spectrum Disorder requires impairments
in all of the following areas of development:
Communication:
The impairment includes both spoken
language and non-verbal skills. People with autism may have no speech
(approximately 50%), or may have difficulty with speech production and/or
conversation skills. There may be a total lack of development of speech,
and this is not compensated by the development of non-verbal modes of
communication (e.g., no use of gestures, facial expression, body posture).
In individuals who have speech, there may be a repetitive and stereotypic
use of language, prosody (i.e. pitch, intonation, rate, etc.) is abnormal,
grammatical structures are often immature, metaphorical language and/or
neologisms may be used (therefore can be understood only by those familiar
with individual’s communication style), and there are impairments in one’s
ability to initiate or sustain conversation with others.
Social interaction:
People with autism often do not relate well with other people, have
difficulty learning to play with others, may not imitate well, and have
difficulty learning how to respond to social games. Manifestations of
impaired social interaction include avoidance of eye contact, lack of
interest in simple social activities, impaired awareness of the presence
of others, minimal interest in establishing friendships or lack of
understanding about rules of social interaction.
Restricted repertoire of activities and
interests:
this includes some of the usual behaviours that are often associated with
autism such as stereotyped and repetitive motor mannerisms or body
movements, distress about changes in routines, preoccupations with parts
of objects and a restricted range of interests.
Associated features:
other features associated with the disorder may include difficulties in
eating, sleeping or toileting, unusual fears, learning problems,
repetitive behaviours, self injury and peculiar response to sensory input.
Approximately 75% to 95% of people with autism have a cognitive
impairment. Moreover, the profile of cognitive skills is usually uneven,
regardless of the general level of intelligence (e.g. functioning is not
at the same approximate developmental level for all areas).
Asperger’s Syndrome:
Children diagnosed with Asperger’s Syndrome usually demonstrate normal
language and cognitive development (onset of speech may be slightly
delayed). Social impairments are evident but more subtle that those
displayed by people with autism.
Rett’s Syndrome:
Rett’s Syndrome is a disorder that has only been reported in females.
Onset occurs after a period of normal development. This is a degenerative
disorder leading to severe neurological problems.
There are specific stereotyped hand movements associated with Rett’s
Syndrome and a curvature of the spine.
P.D.D.
Pervasive Developmental Disorders are characterized by severe and
pervasive impairments in several areas of development: reciprocal social
interaction skills, communication skills or the presence of stereotyped
behaviour, interests and activities. Although the complex of symptoms is
comparable to that of autism, there are fewer symptoms displayed and the
severity of their expression is milder.
P.D.D.N.O.S.
The category of Pervasive Developmental Disorder Not Otherwise Specified
is used when the child exhibits impairment in the development of social
interaction, or verbal and non-verbal communication or when stereotyped
behaviour or activities are present but the criteria for any specific
pervasive developmental disorder is not met. |
