The pervasive developmental disorders (TGD) are a set of alterations that result in a delay and / or deviation from normal development patterns and that more significantly affect the social and communicative areas.
This set of disorders will produce alterations in social interactions and relationships, alterations in both verbal and non-verbal language, in addition to the presence of restrictive or repetitive behavior patterns (García-Ron, 2012).
The American Psychiatric Association (APA) in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), within the denomination pervasive developmental disorders (PDD), includes different types of clinical entities, including: autistic disorder , Rett's Disorder, Disintegrative Disorder, Asperger's and Unspecified Pervasive Developmental Disorder.
In the literature on pervasive developmental disorders, it is common to find allusion to these with the generic name of autistic disorder. However, each of these disorders is a clearly defined entity with its own diagnostic criteria..
Despite this, the current edition of the diagnostic manual, published in 2013 (DSM-V), has proposed a change in the diagnostic criteria for pervasive developmental disorders.
Thus, it establishes that all patients with a clearly defined diagnosis according to the DSM-IV of autistic disorder, Asperger's disease or unspecified developmental disorder, will be given the diagnosis of Autism Spectrum Disorder (DSM-V, 2013).
The rationale for combining individual PDD diagnoses into a single Autism Spectrum Disorder (ASD) category has been questioned. Different researchers refer to autism not as a unitary condition, but to "autism" in the plural, due to the great heterogeneity of this pathology (Federación Autismo Andalucia, 2016).
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According to DSM-IV, pervasive developmental disorder is not a specific diagnosis, but rather a general term under which different specific diagnoses are defined: autistic disorder, Rett disorder, disintegrating disorder of childhood, Asperger's disorder and the disorder pervasive development of unspecified development (Autism society, 2016).
Generally, these are disorders that occur in early childhood, especially before the age of three. Some of the symptoms that parents and caregivers may observe may include:
From the classification shown in the DMS-IV, five types of pervasive developmental disorders are identified:
It is characterized by an alteration in skills related to social interaction, verbal and non-verbal communication, restriction of interests, and stereotyped and repetitive behaviors; unusual response to stimuli and / or presence of developmental disorders.
It is characterized by the presence of a marked inability to establish social relationships adjusted to their age and level of development, together with mental and behavioral rigidity.
It only occurs in girls and is characterized by a marked regression of motor behaviors before 4 years of age. It is usually associated with a severe intellectual disability.
It is characterized by a loss of skills acquired after normal development. It usually occurs between two and 10 years. Almost all the skills developed in the different areas tend to disappear and it is usually associated with severe intellectual disability and seizure-type episodes..
This diagnostic category tries to group all the cases in which there is not an exact match with each of the previous definitions, or the symptoms are presented in an incomplete or inappropriate way..
In general, the data derived from the different epidemiological studies are variable and heterogeneous, largely due to the different instruments used to establish the diagnoses, as well as the differences in the samples studied (AEPNYA, 2008).
Despite this, generalized developmental disorders (PDD) are the most common developmental disorders in early childhood (García-Primo, 2014).
Until recently, different investigations estimated a prevalence of 6-7 cases of pervasive developmental disorder per 1,000 inhabitants (García-Primo, 2014). In addition, among the different diagnostic categories, autism is the most frequent condition, establishing itself at 1% (García-Primo, 2014).
On the other hand, it is more common for this type of pathology to occur in boys than in girls, with an approximate ratio of 3: 1 (García-Ron, 2012).
These types of alterations usually appear before the individual reaches three years of age. Normally, delays or abnormalities in development begin to appear already in the first year of life that can be an alarm signal for their caregivers (AEPNYA, 2008).
Many parents report that "something is wrong" around 18 months and generally go to the doctor when they reach 24 months of age (AEPNYA, 2008).
Only 10% of cases receive an early diagnosis, the rest are not established until approximately two or three years (AEPNYA, 2008).
In general, generalized developmental disorders (PDD) are defined in relation to a series of alterations based on Wing's triad of disorders:
Depending on the specific clinical course of each individual, these alterations will appear to a lesser or greater degree of severity, age or form of appearance.
According to the Spanish Association of Child and Adolescent Psychiatry (2008), the affected areas can be:
Severe difficulties appear in the social sphere, characterized by absence of interpersonal contact, tendency to introversion and isolation or indifference towards people (AEPNYA, 2008).
In the different generalized developmental disorders and specifically in autism, a series of language disorders appear: a) difficulty or inability to understand verbal and non-verbal language; b) difficulty or inability to produce understandable verbal and non-verbal language; c) specific anomalies (echolalia, metaphorical language, neologisms) (AEPNYA, 2008).
Different restrictions will appear in the area of interest. It is very common to observe repetitive, rigid and restrictive behaviors, which lead the individual to present restricted interests, few activities and objects.
It is also common to observe manual stereotypies, alignment of objects or compulsive ritualistic phenomena. Atypical responses may appear to sensory stimuli, concern for lights or noise (AEPNYA, 2008).
Motor incoordination, hyperactivity, self-injurious behaviors, decreased pain threshold, rocking, fluttering, laughter and crying out of context or affective lability (AEPNYA, 2008).
There is no clear consensus about the nature of pervasive developmental disorders. Experimental studies show clear heterogeneity because it is a diagnostic category that encompasses a wide variety of clinical disorders that may have different organic bases (AEPNYA, 2008).
Generally, these disorders are justified by the presence of brain, functional and / or structural abnormalities, which do not have to be common..
Among the etiological factors related to these disorders, genetic factors have been pointed out; neurochemical alterations; the alterations of the immune functions; and environmental factors.
The genetic etiology is not completely established. It is thought that both monogenic and multigenic anomalies may be involved (García-Ron, 2012).
In the case of autism, the results of whole genome scans support the hypothesis that the person must inherit at least 15 to 20 genes, which interact synergistically to express the full autism phenotype.
The recurrence rate in siblings of people with autism is 2.2%, which can reach 8% when all ASDs are included, which means about 50-75 times the risk of the general population (CPG for management Autism Spectrum Disorder Patients in Primary Care, 2009).
Different neurochemical correlates have been identified (serotonin, oxytocin, dopamine, norepinephrine and acetylcholine) that can affect the formation of the central nervous system at different stages of development (CPG for the management of patients with autism spectrum disorders and primary care, 2009).
It has been identified that the presence of IgG-type antibodies against fetal brain proteins in maternal plasma during pregnancy, together with a marked genetic lability, can lead to a global regression of neurodevelopment (CPG for the management of
patients with autism spectrum disorders and primary care, 2009).
Among these types of factors, a series of conditions have been identified that can specifically give rise to the characteristic phenotype of these disorders..
These factors include obstetric complications, vaccinations, opiates, exogenous brain, exposure to mercury, toxic diseases, among others. However, the real incidence of these has not yet been specified in detail in scientific research.
The mean age of establishment of the diagnosis is between 3 and 4 years of age. However, parents report that they had been noticing abnormal signs or symptoms since approximately 18 months, and that it is at two years of age that they begin to seek specialized advice (García-Ron, 2012).
Traditionally, the detection of autism has been characterized by the identification of the warning signs, however, the care services have addressed it in a minimal way, therefore, it has been the parents who are mobilized before the presentation of these alterations.
The American Academy of Pediatrics (AAP) recommends that early detection mechanisms be put in place at both professional and public administration levels.
It is recommended that family doctors perform different screenings for pervasive developmental disorder in routine visits at least twice before the age of two to detect possible warning signs (García-Primo, 2014).
Once behavioral abnormalities are detected early, establishing a definitive diagnosis is often difficult due to the heterogeneity that symptoms and signs can manifest in each individual..
Currently there is no single treatment for pervasive developmental disorders. Some drugs are often used to treat specific behavioral problems (National Institute of Neurological disorders ans Stroke, 2015).
On the other hand, therapeutic and neuropsychological interventions are carried out according to the specific needs of diagnosed individuals (National Institute of Neurological disorders ans Stroke, 2015).
Communication and social alterations will cause a significant delay in the acquisition of school and social learning. Thus, early intervention at the educational level has shown a fundamental role in improving functional performance.
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