Learning disorders: causes, symptoms, diagnosis, treatment

Adequate learning depends on a number of factors, including intact cognitive functions, motivation, familiarity with the spoken language of instruction at school, the level of academic achievement expectations, and the quality of classroom instruction. Low academic achievement can have an adverse effect on self-esteem, leading to social isolation, exclusion from the full cultural life and economic activity of society.

Historical information

Until the 1940s, academic failure in the United States was associated exclusively with mental retardation, emotional disorders, and socio-cultural deprivation. Later, academic failure was explained by neurological causes, and the unfortunate terms "minimal brain damage" (reflecting hypothetical neuroanatomical damage) and "minimal brain dysfunction" (reflecting hypothetical neurophysiological dysfunction) were introduced. Subsequently, the terms "dyslexia" appeared to denote reading disorders, "dysgraphia" to denote writing disorders, and "dyscalculia" to denote disorders in the formation of mathematical skills. It was assumed that these disorders had a common etiology and should have a single treatment strategy. Currently, it is believed that each of these conditions has an independent etiology.

Definition of learning disorders

According to DSM-IV, learning disorders are characterized by inadequate development of scholastic, language, speech, and motor skills that is not associated with overt neurological disorders, intellectual disability, pervasive developmental disorder, or educational disabilities (APA, 1994). ICD-10 uses the term "specific developmental disorders" to describe similar conditions. A learning disorder is diagnosed when an individual's ability is significantly below what would be expected on the basis of his or her age, intelligence, or age-appropriate education. "Substantial" usually implies at least two standard deviations from the norm, as determined by chronological age and intelligence quotient (IQ).

In the United States, educators often use the term "learning disability." The definition of a learning disability is important because it determines the level at which a child can be enrolled in specialized educational classes that operate under a federal program. There are a number of differences between the terms "learning disorder" and "learning disability." A learning disability, according to the Education for All Handicapped Children Act, does not include children whose learning disabilities are caused by visual, hearing, or motor impairments, mental retardation, emotional disorders, or cultural or economic factors. Consequently, many children who, in addition to a diagnosed mental retardation, have reading disabilities that are significantly more severe than would be expected based on their intelligence level, may be denied these services. In response to situations like these, the Federal Committee on Learning Disabilities has proposed a new definition of learning disorder that allows for the diagnosis of this condition in patients with intellectual disability, attention deficit hyperactivity disorder, or social or emotional disorders.

Classification of learning disorders

The DSM-IV identifies the following types of learning disorders.

1. Reading disorder.
2. Disorder of mathematical abilities.
3. Writing disorder.
4. Communication disorders.
5. Expressive language development disorder.
6. Mixed receptive and expressive language disorder.
7. Phonological disorder (articulation disorder).
8. Motor skill disorders.

Because such conditions often co-occur with other disorders, they are classified as Axis II in DSM-IV.

Prevalence and epidemiology of learning disorders

The prevalence of learning disorders remains unknown, primarily because there is no single definition. The Centers for Disease Control and Prevention estimates that learning disorders occur in 5 to 10 percent of school-aged children. Boys predominate among affected individuals, with a ratio of 2:1 to 5:1, although this may be because boys with learning disorders, who are more likely to engage in disruptive behavior, are referred for evaluation more frequently.

Pathogenesis of learning disorders

The origin of learning disorders remains largely unclear and is likely multifactorial. Difficulties in school learning may be related to attention deficit, memory impairment, speech perception or production disorders, weakness of abstract thinking, and organizational problems. These disorders may also be caused by visual or auditory perception disorders. Due to visual perception disorders, the patient may be unable to detect subtle differences in the contours of objects, for example, unable to distinguish between similarly shaped letters (e.g., “p” and “n”) and numbers (e.g., “6” and “9”). There may also be difficulties in distinguishing a figure from a background or establishing distance, which may lead to motor awkwardness. In some cases, the ability to finely differentiate sounds, separate sounds from background noise, or quickly recognize a sequence of sounds is impaired.

Even if learning disorders are biologically determined, their development and manifestations are influenced by sociocultural factors. External factors, such as the “culture of poverty” characteristic of some American city neighborhoods, as well as emotional factors, often cause children to study below their abilities. Such emotional factors include specific personality traits (negativism, narcissism), and the desire to go against parental expectations. The incidence of learning disorders is higher among late-onset children growing up in large families. Smoking and drinking alcohol by pregnant women are associated with a higher incidence of school problems in their children. The long-term effects of medications taken during pregnancy on the fetus are currently being studied. An autoimmune origin of learning disorders is also suggested.

Diagnostic criteria for learning disorders

Diagnosis of a learning disorder requires exclusion of other causes that may cause similar symptoms. Because individuals with learning disorders are often referred to physicians because of inappropriate behavior, it is important to determine whether behavioral problems are a cause or a consequence of academic failure. But drawing this line can be difficult. Below are some guidelines to help resolve this issue. For example, a neuropsychological examination of a child with a primary affective disorder will usually not reveal the partial deficit with “strong” and “weak” cognitive abilities that are characteristic of developmental disorders. The physician should obtain information about the child’s academic performance in all subjects taught, and if particular difficulties are noted in learning in any of them, subject the child to a thorough neuropsychological examination.

The tests used to diagnose learning disorders are based on the cybernetic model of information processing. According to this model, several stages of information processing are distinguished. First, information is perceived and registered, then it is interpreted, integrated and remembered for subsequent reproduction. Finally, the individual must be able to reproduce the information and convey it to others. Psychopedagogical research evaluates the state of intellectual abilities and cognitive style, placing special emphasis on the discrepancy between intellectual potential and academic performance. Such discrepancies are noted when evaluating each test. The current level of school academic skills is measured using standardized achievement tests. It should be remembered that, by definition, half of the children will automatically have below-average results on these tests.

Neurological examination is an important part of the examination, which allows, first of all, to identify microfocal symptoms, and on the other hand, to exclude serious pathology of the central nervous system. For example, if a patient complains of headache, a special examination is necessary in order not to miss a rare neurological pathology, for example, repeated hemorrhages from arteriovenous malformation in the speech zones of the temporal lobe. Often, consultations with other specialists are also necessary, for example, a speech therapist - to clarify the nature of speech disorders, as well as specialists in therapeutic exercise and occupational therapy - to check the main and fine motor skills, as well as sensorimotor coordination.

It is important to diagnose learning disorders as early as possible, as early intervention is more effective and helps avoid psychological trauma that occurs later due to underdevelopment of a particular function. In preschool-aged children, a possible learning disorder may be indicated by a delay in motor and speech development, insufficient development of thinking and other cognitive abilities, revealed in games.

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