Intellectual impairment - mental retardation or dementia (ICD-10: F70, F71, F72, F73, F78, F79) is a permanent decrease in intelligence due to organic damage to the brain. Consequently, this disorder cannot be cured because it is not a disease, but a permanent physiological state (poor development of intellectual qualities, some mental properties, impaired adaptive abilities). Individuals with intellectual disability due to causes other than organic brain damage (e.g., environmental exposure, educational failure, etc.) who have an IQ of 70 or more are considered mildly mentally retarded, but not for clinical reasons.
What it is?
WHO defines intellectual disability as: “a condition of impaired mental development characterized by a specific impairment of skills that occurs during development, covering all elements of intelligence, namely cognitive, language, motor and social abilities.” It can be combined with other disorders or occur without them.
Another characteristic: “Intellectual retardation is the failure to achieve an adequate degree of mental development (<70% of normal) despite educational stimulation in an appropriate manner.”
This is how the American Association on Intellectual and Developmental Disabilities (AAIDD) defines intellectual disability: “Intellectual disability is a decrease in abilities, characterized by significant limitations in mental functioning and adaptive behavior. This lesion occurs before the age of 18.”
In addition to the 18-year limit, in the works of some authors you can find an age limit of 2 years. At the same time, damage that occurs after this age is called dementia.
Causes of intellectual impairment
The human body consists of 100 trillion. cells. Each cell encodes up to 100 thousand genes. The cell nucleus carries a clear program of life, compiled from the contributions of our ancestors. This program is contained in chromosomes and represents the genetic code.
Genes on chromosomes determine the physical and biochemical properties of a person. They are more or less involved in all functions - from individual cells to physical characteristics and development. The complete set of 46 chromosomes is called the cell genome.
Given this complexity, it is not easy to answer the question of the exact causes of low intelligence. Such a disorder can be associated with any circumstances that impede brain development before, during or after childbirth.
When intelligence declines, the reasons lie not only in a person’s genotype or genetic defects. Mental retardation can also be caused by various environmental factors such as drug use, nutritional deficiencies, poverty or cultural deprivation. It has been found that more than 50% of people with intellectual disabilities have more than one cause of the disorder.
Genetic conditions
These include the following factors:
- anomaly of genes inherited from parents;
- disruption of gene connection;
- problems that occurred during pregnancy (infections, excessive exposure to x-rays), etc.
More than 500 genetic diseases are associated with mental retardation. For example, phenylketonuria, a rare gene disorder, is sometimes also called an inborn metabolic disorder because. it is caused by a defective enzyme.
An example of a chromosomal disorder is Down syndrome. These diseases occur sporadically and are mediated by an excessive number or deficiency of chromosomes and changes in their structure.
Fragile X syndrome is a unique genetic disorder of the sex chromosome and is the leading hereditary cause of intellectual disability.
Problems during pregnancy
Alcohol or drug use by a pregnant mother can cause intellectual impairment in the child. Recent studies have shown that smoking also increases the risk of mental retardation. Other hazards include:
- malnutrition;
- severe environmental pollution;
- some diseases during pregnancy, in particular, toxoplasmosis, CMV, rubella and syphilis.
Pregnant women infected with HIV can pass the virus to their baby, which can lead to nerve damage in the future.
Problems during childbirth
Although any condition of unusual stress can damage a baby's brain, premature birth and low birth weight predict serious problems more often than any other condition.
Problems after birth
Childhood diseases such as whooping cough, chickenpox, measles, meningitis, and encephalitis can damage the brain.
Brain damage also occurs due to trauma, such as hitting the head or drowning. Lead, mercury and other toxins in the environment can cause irreparable damage to the brain and nervous system.
Poverty and cultural restrictions
Dementing decline in intelligence occurs in children from disadvantaged sections of the population due to malnutrition, lack of proper hygiene, and medical care.
On average, about 3-4% of the population suffers from mental retardation. This disorder transcends race, ethnicity, education, community and economic status.
What does the term "mental age" mean?
The term "mental age" is used in intelligence testing. This means that the person scored on a standard IQ test comparable to that of the average person of that age in a sample of the population.
Classification of degrees of mental retardation:
- Easy (IQ 50-69).
- Moderate (IQ 35-49).
- Severe (IQ 20-34).
- Deep (IQ 0-19).
- Unspecified.
- Other types of violations.
Mild degree of intellectual impairment
At best, the thinking of a person with a mild intellectual disability is at the level of a high school student. He can study in special educational institutions.
Typically, such a person achieves the ability to use speech effectively in everyday life, maintain a conversation, and pass a clinical interview.
Most people with mild intellectual disability also achieve full independence in personal care (eating, washing, dressing, bladder and bowel control). The main difficulties usually appear in theoretical school classes.
Moderate degree of intellectual impairment
The thinking of a person with moderate mental retardation can be compared to the thinking of a preschool child. He can only learn mechanically, mainly on a practical level, and is able to master general habits and simple skills.
As adults, people with mild intellectual disability can usually perform simple manual tasks, provided the tasks are carefully structured and professional supervision is available.
A completely independent life is rarely possible.
Severe degree of intellectual impairment
The reduced level of skills and emotional development in this group is usually more pronounced. Most people in this category suffer from a significant degree of movement disorder or other related defects mediated by the presence of significant damage or impaired development of the central nervous system. IQ is usually 20–34.
Profound degree of intellectual impairment
A person with a profound mental disability is seriously limited in the ability to understand or follow requirements or instructions. Most people in this category are immobile or have very limited mobility. They have little ability (or are generally unable) to take care of their basic needs; they require constant help and supervision.
A characteristic feature of profound intellectual impairment, especially in mobile patients, is the presence of the most severe forms of common developmental disorders, for example, atypical autism.
Other types of violations
Assessing the degree of intellectual defects is difficult due to concomitant disorders, autism, and behavioral disorders.
Unspecified mental retardation
This term is used when mental impairment is proven, but its extent is difficult or impossible to assess and thus place the person in one of the previous categories.
Classification
Intellectual disabilities in childhood are divided into quantitative and qualitative. The first group includes:
- Impaired mental function.
Slow maturation of the morphofunctional systems of the brain occurs under the influence of unfavorable factors and is expressed by the immaturity of psychomotor and cognitive functions. - Mental retardation.
It is a mental retardation - a persistent congenital or early acquired impairment of intelligence. There are three degrees: mild (moronicity), moderate (imbecility), severe (idiocy). - Dementia.
Acquired persistent or progressive dementia, developing as a result of the loss of formed intellectual functions.
Qualitative intellectual impairments in children are caused by uneven development of mental, psychophysiological, emotional and volitional functions. We are talking about a disorder in cases where the uniqueness of the intellect prevents the child from adapting to the environment at the level of everyday self-care, social interactions, and mastering educational skills. Qualitative changes are found in schizophrenia, early childhood autism, diseases of the sensory organs, and speech pathologies.
Treatment
If co-occurring disorders are present, treatment should include their relief. The most common problems associated with mental retardation:
- cerebral palsy;
- autism;
- schizophrenia;
- Asperger's, Rett's, Down's syndromes;
- epilepsy;
- fetal alcohol syndrome, etc.
Due to some of these diseases, a person with impaired intelligence may exhibit aggressiveness (Asperger's syndrome, schizophrenia), memory impairment (Rett syndrome) and even depression. There is also a link between intellectual impairment and the risk of developing multiple sclerosis.
Caring for a person with intellectual disabilities requires teamwork of several specialists from the following areas of medicine:
- neurology;
- genetics;
- physiotherapy;
- occupational therapy;
- psychology;
- psychiatry;
- special pedagogy;
- speech therapy, etc.
Experts determine the extent of functional limitations, recommend appropriate ways to work with children and adults with intellectual disabilities, and advise on the appropriate choice of compensatory aids or toys.
Supporting skill development is especially important for children with intellectual disabilities. At an early age, stimulation methods include:
- physiotherapeutic methods (e.g. Voight method, Bobath concept, etc.);
- occupational therapy (sensory stimulation, etc.);
- special pedagogical methods;
- special approaches and programs for self-care training;
- some other methods used (occupational therapy, music therapy, etc.).
Classification of intellectual disabilities
Modern classifications of diseases distinguish up to 50 types of intellectual disabilities. The 10th International Classification of Diseases (ICD-10) provides a new classification of mental and behavioral disorders (Class V), which also includes intellectual disabilities*.
According to ICD-10, the classification of diseases of class V - mental disorders and behavioral disorders - has a number of significant differences from the classifications of diseases of previous years. For example: ICD-10 adopts an alphanumeric coding scheme; Thus, diseases of class V are classified under the heading F00-F99.
Throughout the classification, the term “disorder” is used instead of the terms “disease” and “disease.”
The authors of this manual have identified from class V - “Mental disorders and behavioral disorders” - the main diagnostic headings (F7, F0, Fl, F8)1 that are directly related to the clinic of intellectual disabilities, and individual nosological forms from other headings, in which they are most clearly manifested certain changes in cognitive processes, both in children and adults.
This took into account, first of all, the specifics of the practical activities of future specialists - work with children and adolescents with various mental disorders, specific disorders of psychological development, as well as speech development, school skills, etc. However, given that intellectual disabilities are often progressive in nature, and certain nosological forms appear only in adulthood or old age, future specialists in the field of clinical and special psychology, speech therapy, social work, etc. need deep knowledge about the characteristics of intellectual disorders not only in children, but also in adults.
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*Adapted version of class V-ICD-10 dated 01/01/99 is recommended by the Ministry of Health of the Russian Federation for mandatory use in medical institutions.
1 F7 - mental retardation; F0 - organic, including symptomatic mental disorders; F1 - mental disorders and behavioral disorders due to the use of psychoactive substances;
The main clinical picture of most disorders from the categories F0 and F1 consists of intellectual impairment in the form of acquired dementia - dementia. F8 - disorders of psychological (mental) development.
When preparing an adapted version of the classification of intellectual disabilities, along with the use of the main individual diagnostic headings of class V-ICD-10, the authors also considered other options for the classification of dementia. (identification of acquired dementia according to the course of the pathological process and clinical manifestations.)2
Depending on the risk factors, degree, level and volume of brain damage, as well as on the duration of the pathogenic effect, all intellectual disorders are divided into two main groups (Figure 7):
1. Temporary weakening of intelligence (diagram 8).
2. Persistent intellectual impairment.
Persistent intellectual impairment, in turn, is also divided into two groups:
1. Congenital dementia - mental retardation.
2. Acquired dementia - dementia.
However, for a deeper understanding of the clinical characteristics of individual nosological forms leading to persistent intellectual impairment, the classification describes them according to risk factors, severity, course and clinical manifestations (Scheme 9, 10; Table 1).
With brain lesions, milder forms of weakening of mental activity are also observed, which have not reached the level of dementia. Such conditions are called a decrease in the level of personality. Clinically, they are manifested by increased fatigue and irritability, changes in behavior in the form of discomfort, a tendency to solitude, a narrowing of the circle of friends and interests, and mild intellectual impairment. However, with the progradient development of organic brain damage and long-term functional disorder of the nervous system, these conditions worsen and ultimately reach the degree of dementia: Among the large list of mental disorders and behavioral disorders presented, in a version of class V-ICD-10 adapted for use in the Russian Federation, a separate The category identifies a number of disorders that are characterized by mandatory development in infancy or childhood, damage or delay in the development of individual functions (speech, visual-spatial skills, etc.), and a progressive course. It is characteristic that the level of intellectual impairment in most cases ranges from mild to severe degrees of dementia. In certain nosological forms, a normal level of intelligence development is noted.
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2 BME. M., 1984. T. 23. P. 405-406.
However, a common feature of these disorders is a decline in personality. This group of violations in the classification of Fr.
In addition, “Neurotic stress-related disorders” are highlighted under a separate heading. Certain nosological forms of this type of disorder are also characterized by a decrease in personality level and a temporary weakening of intelligence. In cases of a long-term stress factor, manifestations of a persistent weakening of intelligence, predominantly of mild severity, are noted.
In connection with the above, the authors combined these disorders under the heading “Mental and behavioral disorders leading to a decrease in the level of intelligence and personality” (Table 2).
Of all the nosological forms of these disorders, this category includes precisely those pathological conditions in which one or another decrease in the level of intelligence is noted.
The authors do not claim to be an encyclopedic thoroughness of this classification of intellectual disabilities, but given the current lack of a unified taxonomy of acquired dementia, it can be used in the practical activities of specialists when working with children and adults suffering from various types of intellectual disabilities.
Thus adapted in accordance with ICD-10, the version of the classification of intellectual disabilities is scientifically based and is recommended by the authors of this textbook, both for in-depth mastery by students of higher educational institutions, and for widespread use by specialists of various profiles (psychiatrists, neurologists, pediatricians ; special teachers and special psychologists, etc.) in their professional activities.
Chapter 6.
