Mental Retardation - Symptoms

Symptoms of mental retardation

With the entire polymorphism of clinical manifestations, two main criteria typical for most forms of mental retardation can be distinguished, which primarily characterize the so-called nuclear or typical oligophrenia.

• Underdevelopment is of a total nature and concerns not only intellectual activity and the personality of the patient, but also the psyche as a whole. Signs of underdevelopment are revealed not only by thinking, but also by other mental functions - perception, memory, attention, emotional-volitional sphere, etc.
• With total mental underdevelopment, the insufficiency of the higher forms of cognitive activity-generalization and abstraction-comes to the fore. The weakness of abstract thinking is reflected in the peculiarities of perception, attention, and memory.

The structure of mental underdevelopment can be uneven. In this case, it is not limited to typical for mental retardation symptoms. They include options with the availability of additional psychopathological symptoms in relation to the syndrome of general mental underdevelopment. At the same time, one can observe the whole range of mental disorders occurring in intellectually full-fledged persons, whose frequency among these forms of mental retardation is at least 3-4 times higher than in the general population. Complicated symptomatology can be represented by various neurotic and psychopathic disorders, psychomotor disinhibition, cerebral asthenia, psychosis, convulsive and non-convulsive forms of seizures.

Mental retardation is a nonspecific condition that is diagnosed in accordance with the DSM-IV criteria. Its cause can be various hereditary and acquired diseases, many of which have characteristic behavioral manifestations ("behavioral phenotypes"). Among the hereditary diseases that cause mental retardation and characteristic behavioral disorders, include the syndromes of the fragile X chromosome, Turner, Rett, Down, Williams, Prader-Willi, Lesch-Nayhan, Low, and others.

Syndrome of a fragile X chromosome. At the heart of the disease is a mutation in the form of an increase in the number of repeats of the trinucleotide CHH (cytosine-guanine-guanine) in the promoter zone FMR1 on the long arm of the X chromosome (Xq27.3). The carrier man transmits pre-mutation to his daughters (but not to his sons). An increase in the number of repeats of CHH with the development of a "full" (disease causing) mutation occurs during the meiotic cycle in a woman. A complete mutation is characterized by hypermethylation of the FMR1 promoter zone and an increase in the number of repeats of the CHH from several hundreds to many thousands. Each child born by a female carrier has a 50% risk of getting a mutating mutant brittle X chromosome, which can, without appearing clinically, be transmitted through a number of generations before a child with clinical manifestations of the syndrome appears. In expanded form, the disease manifests itself in boys. Characteristic phenotypic features of the disease include mental retardation, an elongated narrow face with protruding ears, a massive lower jaw and a high protruding forehead, a Gothic sky, a strabismus, a low muscular tone, a flat foot, macrochiorism. In addition, there are often stereotypes in the form of waving hands or nibbling of nails, an unusual change in speech, characterized by rapid fluctuating chatter, repetition of individual sounds, words or phrases. Attention disturbances, hyperactivity, delay in motor development, phobic avoidance of communication with peers or strangers are also often noted, but normal relationships with caregivers are established. The allotted look is an eye-catching symptom, often observed in sick boys. In females, a lighter form of the disease is observed, characterized by symptoms of restrictive behavior or social phobia, as well as learning difficulties, developmental disabilities, and attention deficit. At the same time, the coefficient of intelligence (IQ) often remains within the norm. Thus, the syndrome of a fragile X chromosome may be accompanied by symptoms of anxiety, attention deficit disorder, hyperactivity, stereotypes, and sometimes affective disorders.

Turner syndrome. Turner's syndrome (Shereshevsky-Turner) is a chromosomal disease manifested in women with short stature and infertility and resulting from the complete or partial absence of one of the X chromosomes. With a neuropsychological study, these individuals have difficulty in performing tests for visual and spatial functions and solving non-verbal problems. Behavior in patients manifested features of immaturity, hyperactivity, "nervousness". They develop a bad relationship with their peers, there are difficulties in learning, violation of attention.

In patients with Turner's syndrome, estrogen replacement therapy has been carried out for several decades already, contributing to the development of secondary sexual characteristics and the maintenance of tissue trophism, including bone tissue. Estrogen therapy has a positive effect on the self-esteem of patients. To accelerate the growth in patients with Turner's syndrome, it has recently been suggested to use somatotropic hormone.

Down Syndrome. The disease was first described by John Langdon Down (John Langdon Down). In 95% of cases, the disease is associated with stromaemia on the 21st chromosome. It is characterized by a fold in the inner corner of the eye (epicanth), a flattened back of the nose, the presence of a single lateral palmar groove, a decrease in muscle tone, a pathology of the heart. Patients with Down's Syndrome are usually sociable and can come into contact with others. Nevertheless, they reveal a pronounced lack of communicative abilities, manifested in everyday activities, a disruption in the development of social skills, a weak development of expressive speech (with greater safety of the receptive aspect of speech). However, the main cause of social maladjustment of patients is early developing dementia. In addition, patients can have dyskinesia and affective disorders.

Williams Syndrome. Williams syndrome is a hereditary disease characterized by deletion of one or more genes of the vokus coding for elastin (7qll.23), or near it. The disease is characterized by "elf face", pathology of the cardiovascular system, high blood pressure, increased calcium levels in the blood, behavior changes. Very characteristic is the external appearance of patients - almond-shaped eyes, oval-shaped ears, full lips, small chin, narrow face, large mouth.

Patients with Williams syndrome quite easily come into contact with adults, but their relationships remain superficial. Often observed violations of attention, increased anxiety, poor relationships with peers, a violation of the development of visual and spatial and motor skills. In addition, signs of autism, delayed psychomotor and speech development, hypersensitivity to sounds, unusual eating habits, perseverative actions are revealed.

The Prader-Willi syndrome is caused by microdeletion on the 15th chromosome (loci 15qll and 15ql3), which the patient inherits from the father. The disease was first described in 1956 by Prader as a syndrome characterized by obesity, short stature, cryptorchidism, and mental retardation. Other signs of this condition are obsessional thoughts about food, compulsive eating behavior, a massive body, underdevelopment of sexual characteristics, low muscle tone.

Individuals with Prader-Willi syndrome have a delay in speech and motor development, learning difficulties. Expressed eating disorders, which include the theft and storage of food, gluttony with the disorderly absorption of various types of food. Often, there are sleep disorders, irritability, hot flashes, increased pain threshold. For this disease is also characterized by a wide range of stereotypical actions, including scratching the skin, nipping the nails, picking in the nose, biting the lips, pulling out the hair.

Lesch-Nayhan syndrome is inherited as a recessive disease associated with the X-chromosome and manifests itself only in boys. It is associated with an inborn violation of purine metabolism due to the absence of hypoxanthine-guanine phosphoribosyltransferase. The disease is characterized by an increase in the level of uric acid (hyperuricemia), impaired renal function, arthralgia, choreoathetosis, spasticity, autoaggressive actions, mental retardation.

For Lesha-Nayhan syndrome, continuous, expressed self-injurious actions are particularly characteristic. They are quite variable, which, apparently, is associated with internal impulses, and not external influences. Patients are often unable to slow their own self-damaging actions, however, anticipating their beginning, they sometimes ask others to restrain them. Aggression against other persons in this disease can be expressed to the same extent as ay-toaggressive actions. Studies have shown that lowering the level of stress, removing the teeth and physical containment measures that are often used to combat auto-aggressive actions have little effectiveness. The severity of autoaggressive actions usually does not change with time. The outcome to a certain extent depends on the age of the beginning.

The creation of the laboratory model of the Lesch-Nayhan syndrome made it possible to better understand the pathogenesis of autoaggressive actions. Transgenic mice deficient in hypoxanthine-guanine phosphoribosyltransfer were not found to have any neurological dysfunction. Nevertheless, after the appointment of 9-ethyladenine, a neurotropic drug acting in the basal ganglia, these animals developed autoaggressive behavior. Studies using positron emission tomography (PET) revealed a significant decrease in the number of dopaminergic nerve endings and bodies of dopaminergic neurons in the brain. Apparently, dopaminergic dysfunction, which is systemic in nature and associated with impaired brain maturation, plays an important role in the development of characteristic mental disorders. Regular introduction of a dopamine reuptake inhibitor to healthy adult mice provokes autoaggressive actions, which coincides in time with a 30% decrease in dopamine concentration in the striatum, with an increase in serotonin turnover and a significant increase in the synthesis of substance P and neurokinin A. In this case, autoaggressive behavior can be blocked by the administration of antagonists of dopamine D1- or D2-peuerrropob. With these data, there are consistent reports of the efficacy of risperidone in Lesha-Naikhan syndrome.

Cornelia de Lange syndrome. In 1933, Cornelia de Lange, a Danish pediatrician, described two children who had similar symptoms: low birth weight, slow growth, short stature, microcephaly, thin intergrown eyebrows (synophrys), long eyelashes, a small upturned nose, thin, twisted lips. In addition, hypertrichosis, small brushes and feet, partial fusion of the second and third toes (syndactyly), flexion of the little finger on the hands, gastroesophageal reflux, epileptic seizures, heart defects, wolf mouth, intestinal pathology, feeding difficulties can be detected in patients.

Most patients with Cornelia de Lange syndrome have mild or severe mental retardation. Although the type of transmission of this disease is not completely established, in the offspring of patients with mild manifestations of the syndrome there may be a developed form of the disease. In behavior, features characteristic of patients with autism are manifested, such as poverty of mimic expression of emotions, autoaggressive actions, stereotypes, pleasant sensations with vestibular stimulation or impetuous movements.

Low syndrome. Oculocerebral and Low syndrome is a disease linked to the X chromosome, characterized by congenital cataracts, cognitive impairment, renal tubular dysfunction. In this disease often there are such forms of inadequate behavior as stubbornness, hyperactivity, temper, and stereotypes.

Mental retardation and auto-aggressive / aggressive actions

Auto-aggressive (self-damaging) actions in persons with mental retardation often consist of constant head blows against the wall, bites, strikes on oneself. Other types of auto-aggressive actions are possible - scratching, squeezing of limbs, falling to the floor. Autoaggressive actions are detected in about 5-15% of patients with mental retardation and they are often the reason for placing patients in specialized psychiatric institutions. Since these actions often have many causes, in the study of the patient, one must evaluate the influence of external, medical and psychological factors on them. The initial study should include a functional analysis of behavioral determinants using abbreviated forms. Associated somatic diseases often provoke autoaggressive actions, especially when it is impossible to report their physical discomfort.

Aggressiveness towards other people often accompanies self-damaging actions, but can also occur independently. Sometimes there are peculiar fluctuations between the manifestations of aggression and autoaggression, when the strengthening of some is accompanied by the weakening of others.

Concomitant mental disorders in patients with mental retardation

In children and adults with mental retardation, comorbid psychiatric disorders are often identified. In general, 50% of people with mental retardation are diagnosed with certain mental disorders that require treatment. The high prevalence of mental disorders in this category of patients is due to various factors: primary disease, genetic predisposition, social disorder, unfavorable family situation. It is assumed that people with mild mental retardation develop the same mental disorders as those without mental retardation, while with more moderate or severe mental retardation, more specific behavioral disorders develop, common developmental disorders. The identification of the nature of behavioral disorders is critical to the choice of effective therapy. Accurate diagnosis is impossible without obtaining information from parents, teachers, employers, relatives. To establish the baseline and monitor the progression of patients, it is recommended that standardized scales be used.

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