Lecture No. 2. Forms, causes and degrees of mental retardation
3. Degrees of mental retardation.
4. Forms of oligophrenia.
5. Forms of dementia.
1. Forms of mental retardation.
The first attempt to differentiate mental retardation was made by Philippe Pinel in 1806, who designated mental retardation with the term “idotia” and identified four of its types. It was in this taxonomy that the division of dementia into congenital and acquired forms was first outlined, which still exists today. Mental retardation, according to modern clinical and psychological-pedagogical concepts, can be represented by two main forms of oligophrenia and dementia. These forms differ in the duration of action of the pathogenic (harmful) factor.
At mental retardation the pathogenic effect occurs in the prenatal, natal or early postnatal period (the first 2-3 years of life, when the most important mental functions are not yet formed), which causes such a picture of mental development as underdevelopment, and this underdevelopment has the character of a total lag in the development of all mental functions and non-progression (no increase) of intellectual defect. Among the forms of mental retardation, oligophrenia, or general mental underdevelopment, is the most common. In this case, the highest mental functions and the cognitive sphere of the individual have the greatest deficiency, since the physiological basis of their formation is the upper layers of the cerebral cortex, which are damaged. The compensatory capabilities of such children are sharply limited (although not completely excluded) due to the fact that organic brain damage is diffuse in nature, i.e. The entire area of the upper layers of the cerebral cortex is affected. This criterion refers to the most typical part of mental retardation, and not to the entire range of these conditions. So, D.N. Isaev argues that “..with mental retardation, totality and predominant underdevelopment of the phylo- and ontogenetically youngest brain systems do not always occur. Mental underdevelopment may be due to a predominant lesion of more ancient deep formations, which impede the accumulation of life experience and learning.”
At dementia the pathogenic factor acts on the central nervous system in the period after 2-3 years, when most of the brain systems have already been formed and the disorder bears signs of damage to previously formed functions. At the same time, those functions that have recently taken shape or are in a sensitive period of formation receive the greatest damage. Thus, another feature of the development of children with dementia is a certain asynchrony (unevenness) in the development of mental functions, due to the preservation of some functions and the collapse of others.
If signs of underdevelopment are combined with signs of damage, we speak of dementia of oligophrenic origin .
2. Causes of mental retardation.
Causes of mental retardation
The causes of oligophrenia can be various factors of an exogenous (external) and endogenous (internal) nature that cause organic disorders of the brain.
Classification of brain lesions by time of occurrence:
prenatal (before childbirth);
intrapartum (during childbirth);
postnatal (after childbirth).
Classification of brain lesions by pathogenic factors:
hypoxic (due to oxygen deficiency);
toxic (metabolic disorders);
inflammatory (encephalitis and meningitis with rubella, toxoplasmosis);
traumatic (accidents, as well as compression of the brain during childbirth, with hemorrhages);
chromosomal genetic (Down's disease, Felling's disease, etc.);
intrasecretory hormonal;
degenerative;
intracranial neoplasms (tumors).
Of particular note is a group of factors that also lead to mental retardation - alcoholism, drug addiction, and substance abuse. Firstly, the breakdown products of alcohol and drugs (toxins), thanks to the common circulatory system of the mother and fetus, poison the developing fetus. Secondly, long-term use of alcohol and drugs (as well as their substitutes) cause irreversible pathological changes in the genetic apparatus of the parents and cause chromosomal and endocrine diseases in the child.
Causes of dementia
1) dementia as a result of severe trauma, brain tumors or the action of a toxic substance (for example, carbon monoxide), low activity of the thyroid gland, encephalitis, lack of vitamin B12, AIDS, etc., which destroy brain cells, develops suddenly in young people;
2) the most typical cause: progressive diseases. At the same time, the disease develops slowly and affects people over 60 years of age, like senile dementia as a result of Alzheimer's disease, Pick's disease, hydrocyanic dementia, Parkinson's disease (infrequently), but dementia is not a normal stage of aging, it is a severe and progressive decline in mental abilities over time. While healthy older adults sometimes do not remember details, those with dementia may completely forget recent events;
3) dementia as a result of vascular disorders of the brain (in the post-stroke period);
4) dementia developing as a result of mental illness (schizophrenia, epilepsy).
Characteristics of mental retardation
Plan
1. Signs of mental retardation
2. Types of mental retardation
3. Degrees of mental retardation
1. Signs of mental retardation
Mental retardation is a severe, irreversible systemic impairment of cognitive activity that occurs as a result of diffuse organic damage to the cerebral cortex.
In this definition, the presence of three characteristics should be emphasized:
1) organic diffuse damage to the cerebral cortex;
2) systemic intellectual impairment;
3) the severity and irreversibility of this disorder.
The lack of at least one of these signs will indicate that we are not dealing with mental retardation, but with some other type of dysontogenesis. Really:
Underdevelopment of mental activity in the absence of organic damage to the cerebral cortex is a sign of pedagogical neglect, which can be corrected;
Local damage to the brain can cause loss or disorder of one or another mental function (impaired hearing, speech, spatial gnosis, visual perception, etc.), but the intellect as a whole is preserved and there is the possibility of compensation for the defect;
Functional disorders of brain structures can lead to temporary defects in cognitive activity, which under certain conditions can be eliminated;
An insignificant decrease in intelligence limits a person’s ability to master certain types of complex cognitive activity, but does not affect the success of an individual’s independent social adaptation;
Organic brain damage does not necessarily cause impairment of cognitive functions, but can cause disorders of the emotional-volitional sphere and disharmonious development.
It should be noted that not all defectologists agree with this definition. For example, L.M. Shipitsyna believes that with mild mental retardation, organic brain damage does not always occur. Some scientists expand the concept of mental retardation to include cases where developmental lag is predetermined by unfavorable social conditions, deprivation, and pedagogical neglect. Indeed, pedagogical neglect can be so deep that it leads to irreversible changes in higher nervous activity.
The child misses the sensitive periods of formation of the most important higher mental functions, in particular speech, and actually stops at the natural stage of development.
According to the definition of D.M. Isayeva (2005), mental retardation is a set of etiologically different (hereditary, congenital, acquired in the first years of life), non-progressive pathological conditions that result in general mental underdevelopment with a predominance of intellectual defect and lead to complications of social adaptation.
2. Types of mental retardation
Depending on the time of occurrence, mental retardation is divided into two types - mental retardation and dementia.
Mental retardation is a type of mental retardation that occurs as a result of organic damage to the brain in the prenatal, natal or early (up to three years) period of childhood and results in total mental underdevelopment.
It is important to note that mental retardation is determined not by etiological factors, but by the early influence of these factors on the brain. That is, a very diverse hereditary, congenital, acquired harmfulness in the prenatal and early postnatal periods predetermine general mental underdevelopment. The clinical manifestations of oligophrenia do not depend on the causes of its occurrence, unlike dementia, in which the structure of the defect is to a certain extent determined by etiological factors.
For example, the pathogenesis and psychological characteristics of children with traumatic dementia and dementia that arose as a result of neuroinfection are significantly different, while mental retardation predetermined by trauma or infection have the same symptoms.
As you know, the brain of a newborn child has not yet completed its formation. The formation of cork structures, the establishment of connections between cortical neurons, and the myelination of nerve fibers occur in parallel with the mental development of the individual and largely depend on the experience that the child acquires.
Due to the harmful effect on the cerebral cortex in the early period, neurons turn out to be immature or blocked and cannot fully perform their functions, which complicates the process of forming connections between them. Neurodynamics in mental retardation are characterized by weakness of the obturator function of the cerebral cortex, instability of connections, inertia and weakness of nervous processes, insufficiency of internal inhibition, excessive irradiation of excitation, and difficulties in the formation of complex conditioned reflexes.
Therefore, the mental development of an oligophrenic child is carried out on an abnormal basis. An early period of damage to the cerebral cortex leads to a more pronounced underdevelopment of functions that have a longer period of maturation, which, in turn, determines the hierarchy in which regulatory systems and the highest level of organization of any mental function suffer first. The primary defect in oligophrenia is associated with total underdevelopment of the brain, especially in the phylogenetically youngest associative zones.
Secondary defect in oligophrenia, for V.V. Lebedinsky, has a circular character, predetermined by two coordinates of underdevelopment: “from bottom to top” - insufficiency of elementary mental functions creates an unfavorable basis for the genesis of verbal-logical thinking; “from top to bottom” - underdevelopment of higher forms of thinking prevents the restructuring of elementary mental processes, in particular, the formation of logical memory, voluntary attention, reference perception, and the like. The formation of a secondary defect is predetermined by cultural deprivation.
In the structure of dysontogenesis in oligophrenia, there is a violation of interanalyzer connections and, accordingly, isolation of individual functions. Characteristic of oligophrenic children is the separation of speech from action, comprehension, understanding of material from its memorization.
Oligophrenia has a residual (non-progressive) character, that is, it does not have a tendency to progress - to deepen the degree of severity. This circumstance and the relative preservation with a mild degree of motivational-need, emotional-volitional sphere, purposefulness of activity, the absence of encephalopathic and psychotic disorders provide the possibility of satisfactory dynamics of development and the effectiveness of pedagogical influence. But with oligophrenia, phenomena of underdevelopment are observed in the dynamics of mental development at all stages.
The following are the main signs of oligophrenia:
The presence of an intellectual defect, which combines with disorders of motor skills, broadcasting, perception, memory, attention, emotional sphere, voluntary forms of behavior;
Total intellectual deficiency, that is, underdevelopment of all neuropsychic functions, impaired mobility of mental processes;
The hierarchy of an intellectual defect, that is, the overwhelming insufficiency of abstract forms of thinking against the background of underdevelopment of all neuropsychic processes. Underdevelopment of thinking is reflected in the course of all mental processes: perception, memory, attention. First of all, all functions of abstraction and generalization, comparisons based on essential features, and understanding of figurative meaning suffer; components of mental activity associated with the analytical and synthetic activity of the brain are disrupted.
At the same time, higher mental functions, which are formed later and are characterized by volition, are less developed than elementary ones. In the emotional-volitional sphere, this turns out to be the underdevelopment of complex emotions and voluntary forms of behavior. Consequently, oligophrenia is characterized by non-progression, totality and hierarchy of mental development disorders, relative preservation of the personal aspect of cognitive activity. This marked type of mental retardation differs from dementia.
Dementia is a type of mental retardation that occurs as a result of damage to the cerebral cortex in the period after two to three years and results in a significant decrease in intellectual capabilities and a partial collapse of already formed mental functions.
Since the formation of the cerebral cortex is mainly completed at the age of 16-18, the phenomena of degradation are accompanied by mental underdevelopment
The nature of desontogenesis in dementia is determined by the combination of a gross violation of a number of formed mental functions with the underdevelopment of ontogenetic early formations (frontal systems), as a result, the frontal-subcortical interaction suffers. Along with the partial loss of individual cortical functions, disorders of the emotional sphere are primarily observed, often with disinhibited trains, severe disturbances in purposeful activity and the personality as a whole.
Damage leads to phenomena of isolation of individual systems, disintegration of complex hierarchical connections, often with a gross regression of intelligence and behavior.
Dementia is characterized by partial impairment of mental functions. This means that some of them are more damaged, while others are less. Complications of cognitive activity are predetermined not so much by disturbances in thinking as by gross disorders of focus, attention, memory, perception, emotions, as well as the extremely low intensity of the desire for achievement. In dementia, neurodynamic processes are significantly affected, resulting in inertia of thinking, rapid exhaustion, and disorganization of mental activity in general.
Moderate degree of mental retardation (mild imbecility)
This is an average degree of mental underdevelopment, accounting for 10% of the total number of mentally retarded people. Its etiology can be both hereditary defects and the consequences of organic brain damage. It is characterized mainly by unformed cognitive processes (concrete, inconsistent, slow thinking) and the inability to form abstract concepts. IQ ranges from 35-49 or 54.
Static and locomotor functions. They develop with a significant delay and are not sufficiently differentiated. Their coordination, accuracy and pace of movements are impaired. Movements are slow and clumsy, which interferes with the formation of a complex mechanism of running and jumping (kinetic apraxia). Mentally retarded people have difficulty reproducing even given movements or postures (postural apraxia). In this case, pathological synkinesis often appears. They have great difficulty performing activities that require switching movements or quick changes. In some, motor underdevelopment is manifested by monotony of movements, slowness of their pace, lethargy, and awkwardness. In others, increased mobility is combined with lack of focus, disorder, and lack of coordination of movements. Severe defects in motor underdevelopment can interfere with the formation of self-care skills that require fine movements of the fingers: when lacing shoes, fastening buttons, tying ribbons (apraxia of dressing). Most developmentally delayed individuals require constant assistance with many household chores, and some require supervision.
Attention disorders. Everyone's attention is impaired. It is difficult to attract, is unstable and distractible. Extremely weak active attention prevents the achievement of the goal. Under favorable conditions, it can be significantly improved; it is possible to achieve more active inclusion in classes with the teacher, switching in the process of performing the mastered activity.
Disturbances in the processes of sensation and perception. The sensory sphere is very impaired. The development of visual, auditory and other analyzers lags behind. There are often gross anomalies of vision and hearing. However, even if they are preserved, many do not know how to use them. Objects and phenomena are perceived in general terms. There is no activity of perception, they are not able to identify the features of what they perceive and compare them with those of another object. The inability to analyze, search, and fully comprehend perceived information leads to chaotic, unfocused activity. As a result, they cannot navigate the situation on their own and require constant guidance. Correction of emerging sensory abilities can improve the habilitation of these children.
Thought disorders. The moderately mentally retarded have a very limited supply of information and ideas. They have difficulty operating with existing ideas. Their thinking is concrete, inconsistent, and slow-moving. The development of even visual thinking suffers. The formation of abstract concepts is either inaccessible or sharply limited to the most elementary generalizations. They can be taught to group clothes and animals. They are able to establish differences only on specific objects. They are completely incapable of operating with abstract concepts. Conceptual generalizations are formed with great difficulty or occur at the situational level.
These thinking disorders are manifested in the extremely inadequate use of objects when solving visual and practical problems: everyday life, play, constructive, in which a visual or represented example acts as a means of solution. Such patients do not know how to analyze a subject, apply techniques of comparison, transfer, and targeted search. They are made difficult by establishing connections between individual parts of the task. Because of this, there is a lack of focus, speed and accuracy of reactions, switching from one action to another; They do not have developed self-control.
It is not possible to compose a coherent story based on the plot of the most elementary picture: most often the individual objects depicted are named. They cannot arrange pictures in order, united by a single plot, and understand the sequence of what is happening. Judgments are poor, and are a repetition of heard advice and recommendations.
Some moderately mentally retarded people learn all the letters, combine them into syllables, and even read short texts. But they do not comprehend what they read. They perceive it fragmentarily and therefore convey the content in unrelated passages. They assimilate the material unconsciously, mechanically. They master ordinal counting and perform simple arithmetic operations on specific material. They fail to count abstractly within the top ten. They cannot solve problems: the condition of the problem is not retained in memory, and semantic connections are not established.
The main difficulties of moderate mental retardation when solving problems: 1. weak acceptance of the task due to the absence or insufficiently strong motivation, avoidance of the task, mental passivity; 2. lack of orientation in the task, i.e. understanding the connections between links; 3. inability to “meaningfully” organize one’s activities to complete a task, i.e. sequential transition from one action to another, making connections between actions, inability to correctly use visual aids to solve a problem.
Speech disorders. Patients slowly, with a lag of 3-5 years, develop understanding and use of speech, and its final formation is limited. Speech development usually corresponds to the degree of mental retardation. At the same time, the child understands the interlocutor’s speech to a very limited extent, satisfactorily capturing intonations, gestures and facial movements.
In the future, especially under the influence of teachers, speech develops, but its understanding is ultimately determined by personal experience. Expressive speech is limited to single words or short sentences. The vocabulary is poor, consisting of the most frequently used words and expressions. After several years of training, they learn the names of household items and vegetables.
The pronunciation side of speech is defective, speech is almost devoid of modulations, pronounced tongue-tiedness, there are violations of the structure of many words and agrammatism. The most common prepositions are used, children confuse prepositions and replace them.
They manage to develop the ability to use their speech for communication purposes. In the process of communication, they know how to ask others for the items they need and dare to ask questions. In rare cases, the child’s speech is a stream of meaningless cliches pronounced in previously heard intonation (echolalic speech). The origin of this disorder is associated with predominant damage to the frontal lobe of the cerebral cortex or hydrocephalus. In 20% of moderately mentally retarded children, speech does not appear at all due to damage to the speech areas of the cortex.
Memory disorders. Memory is underdeveloped: its volume is small, but by adolescence it can increase, reaching the level found in mildly mentally retarded children. Long-term memory improves better than short-term memory. When reproducing captured material, distortion often occurs. Voluntary memorization is impaired. Both logical and mechanical memory suffers. Children with moderate mental retardation according to the correctional school program (8th type) are unteachable.
A small part of them (mainly due to good mechanical memory) master the basic skills necessary for reading, writing and basic calculation. Educational programs (in special classes of correctional schools or boarding schools) can provide them with the opportunity to develop limited potential and expand the range of self-care skills and orientation in the immediate environment. Hardly acquired knowledge is applied mechanically, like memorized cliches.
As a result of training through repeated visual demonstrations with gradual complication of the task over several years, it is possible to prepare adolescents for work and life in a work community. In addition to labor lessons, it is necessary to strengthen reading and numeracy skills related to labor processes. Moderately mentally retarded adults, calm and amenable to guidance, are usually capable of simple practical work with constant instructions from an instructor. Independent labor activity is not available to them.
Emotional-volitional disorders. Independent living is not possible. However, such people may be mobile, physically active and most show signs of social development, i.e. are able to establish contacts, communicate, and participate in basic social activities organized by educators.
The most typical personality traits of moderately mentally retarded people are: lack of initiative, independence, inertia of the psyche, a tendency to imitate others, a combination of suggestibility with negativism, instability in activity combined with inertia and stiffness.
The relative integrity of their affective life is reflected in their sensitivity to other people's assessments of them. Violations of the emotional-volitional sphere include a lack of emotional diversity, undifferentiated feelings, as well as their inertia and stiffness. Their self-esteem is unique: they put themselves in first place, their friend in second, and their teacher in third. This can be explained by their better understanding of peers compared to adults. As a result of the correction process, their self-esteem can often be changed. They begin to give credit to their teachers.
Even if impulses arise as the personality matures, they are weak and quickly depleted.
Characteristic asynchrony development of different areas of the psyche: some have a higher level of visual-spatial skills compared to the results of tasks that depend on the development of speech. For others, significant clumsiness is combined with some success in social interaction and basic conversation. Levels of speech development vary: some patients can take part in simple conversations, others have a speech reserve sufficient only to communicate their basic needs. Some patients never acquire the ability to use speech, although they can understand simple instructions and learn manual signs that allow them to some extent compensate for their speech deficits. Such asychrony in the development of different spheres of the psyche of moderately mentally retarded children is apparently etiologically related to the consequences of organic brain damage.
A small proportion of children have no need for communication. The majority have developmental disorders that have a great influence on the clinical picture: some are good-natured and friendly; others are dysphoric, angry, aggressive; still others are stubborn and lazy; the fourth are sluggish, aspontaneous, inactive.
Many experience increased and perverted drives, including disinhibition of sexuality. They are prone to impulsive actions. Epileptiform seizures often occur. Moderately mentally retarded children exhibit neurological symptoms (paresis, paralysis), as well as signs of physical developmental defects: underdevelopment of limbs, fingers, disturbances in the formation of the head, underdevelopment of internal organs, hypogenitalism, defects of the face, eyes, ears. Somatic manifestations of associated diseases (bronchial asthma, stomach ulcer) are possible.
Most people with mild mental retardation are able to cope without assistance. Basic mental disorders are sometimes complicated by other neuropsychic pathologies - neuroses, psychoses. However, the limited development of their speech makes it difficult to identify.
