Pervasive developmental disorders

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Pervasive developmental disorders (PDD) is a group of congenital disorders in the field of motor skills, communication, language and perception. Diseases included in pervasive developmental disorders (PDD) do not have a large impact the life expectancy, however, impede functioning in the society. They are incurable, but with early diagnosis, it is possible to adjust education to child’s needs, which significantly facilitates development of social and language skills. PDD mainly includes such nosological units, as Rett’s syndrome, Heller’s syndrome, infantile autism and other disorders from the spectre of autism, e.g. Asperger’s syndrome, childhood disintegrative disorders. Diseases included in PDD are incurable, but with early diagnosis, it is possible to adjust education to child’s needs, at the same time, significantly facilitating development of social and language skills. Lack of early diagnosis and therapy, at the same time, appropriate help, can lead to intellectual disability.
The spectre of autism is very inhomogeneous group of disorders in every aspect: Three key symptoms must be listed as typical:

  • disorders of social communication patterns,
  • disorders of establishing relations with the environment,
  • disorders of activity and interest patterns

PDD general characteristics

Pervasive developmental disorders most often mean autistic disorders, i.e. infantile autism, atypical autism or Asperger’s syndrome. PDD group is, nevertheless, wider than the autistic spectrum and includes other diseases - Rett’s syndrome and Heller’s syndrome as well as other wide developmental disorders, which are not included in diagnostic categories. All diseases included in PDD manifest themselves in the form of difficulties in social contacts, problems with communication, untypical behaviours and, often, in the form of physical weakness. If a person does not meet all the diagnostic criteria for any of pervasive developmental disorders, then Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS) is diagnosed. In most cases, PDD is diagnosed in early years of child’ life and first disease symptoms can be observed even in the neonate period.
All pervasive developmental disorders have specific common symptoms which include:

  • untypical use of objects and toys,
  • difficulties in understanding words,
  • speech difficulties,
  • problems with establishing contact with other people,
  • lack of copying other people,
  • reluctance to physical contact,
  • reluctance to any changes,
  • repetition of specified, stereotypical movements.

So far, it has not been exactly established what is the cause of pervasive developmental disorders. It is suspected that mainly developmental disorders of the foetal period impact the occurrence of pervasive developmental disorders. However, no single gene which causes PDD can be distinguished. It is assumed that neurobiological dysfunctions which impede correct brain functions are responsible for autistic disorders. Boys more often than girls fall down with PDD, except for Rett’s syndrome which mainly concerns girls.

2. Types of pervasive developmental disorders

General features of PDD include difficulties in language and communication development, problems in motor development and in the socialisation zone. Disorders concern basic mental functions, such as concentration, perception, motor skills, which impede everyday functioning and contact with people. However, any nosological unit included in PDD has slightly different symptoms. How does autism differ from Asperger’s syndrome or Rett’s syndrome?



Infantile autism

Boys fall down with autism more often than girls. The basic syndromes of autism include: total lack of speech or delayed learning to speak, inability of social interactions, preferred loneliness, compulsion of environment invariability, avoiding eye contact, reluctance to closeness and hugging, narrow interests, speech disorders (failure to differentiate pronouns, e.g. I and you, echolalia), reading messages literally, inability to understand allusions, metaphors, irony, jokes, autistic isolation, repetition of ritual, stereotypical motions, compulsive ordering objects, hypersensitivity to stimuli in environment, inability to read emotions of other people, easiness of mechanical memorisation, lack of reaction to one’s own name, inability to copy others, problems with non-verbal communication, lack of smile, playing with toys in the manner contradictory to their intention, aggression and auto-aggression, etc. Not all autistic children manifest all the aforementioned features. Each autist is different and particular intensification of symptoms is other in each person. Autism develops until the third year of life. When a child does not manifest all deficits necessary to diagnose autism or when a disease is visible later (after third year of life), then, it is a case of atypical autism.

Asperger’s syndrome

Asperger’s syndrome is most often treated as a more gentle type of autistic disorders. Symptoms are similar as in case of infantile autism, but speech development and intellectual development are significantly less impeded than in case of “pure” autism. The main symptoms of Asperger’s syndrome are: impeded social skills, problems with cooperation with other people, problems with understanding metaphoric language, limited interests (isolated field of knowledge), connection to routine, problems with facial expression and non-verbal expression of feelings, avoiding eye contact and physical closeness, peculiar behaviours. Correct cognitive development, logical communication and larger independence allow a person with Asperger’s syndrome to achieve more than in case of an autistic person.

Rett’s syndrome

Rett’s syndrome is a neurological syndrome, genetically conditioned. In the most cases, it occurs in girls. In addition to impeded mental functions, motor disability is also observed. A child usually develops normally from its birth to about 6-18 month of life. Later, the following symptoms can be observed: loss of manual efficiency and ability to speak, stereotypical hand movements (placing in the mouth, clapping, knocking), low growth, small head (secondary microcephaly), small hands. gnashing teeth, muscle contractures,  disorders of motor coordination, difficulties in walking, spasticity, epileptic seizures, panic attacks, avoiding eye contact, problems with social contacts, lack of smile, misunderstanding speech.

Heller’s syndrome

Heller’s syndrome is rather specified as childhood disintegrative disorder (CDD). The disease has its outset quite late when compared with other PDD since it is after third year of child’s life. Between the second and fourth year of life, a child loses already acquired motor, language and social skills. Symptoms start to be similar to infantile autism syndromes. A child can stop to speak, play and interact with peers. A child is afraid without a visible reason, easily loses their temper, become disobedient and has negative attitude. In the Heller’s syndrome, until the fourth year of life, a child can develop totally normally, but at one stage, they quite quickly loses their skills. Hallucinations and decreased intellectual skills are also characteristics symptoms.

3. PDD diagnosis and therapy

The most of pervasive developmental disorders are diagnosed prior to the third year of child’s life on the basis of detailed child observation and talk with parents. The earlier the diagnosis is made, the faster intervention and larger chances that a child can manage well everyday duties and social requirements in its adult life. Early psychotherapy also disables development of other disorders secondary to PDD, e.g. depression. The treatment plan must be individually prepared for each patient and depends, most of all, on such factors as:

  • child age,
  • child’s general health condition,
  • type of diagnosed disorder,
  • disorder extent,
  • child’s family situation,
  • child’s susceptibility to therapeutic intervention.

Therapy of pervasive developmental disorders can include individual and group therapy, speech therapy classes, psychoeducation for parents, sensory integration, etc. Unfortunately, so far, no manner of successful PDD counteraction has been found.