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What is expressive alalia?
Last reviewed: 23.04.2024
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Among the many violations of speech functions in children, such a form of language development disorder as expressive alalia (from the Greek lalia - speech) stands out.
This disorder manifests itself in the fact that children who understand speech experience difficulties with active oral statements and expressions (in Latin - expressio), that is, in a persistent violation of the assimilation of the system of language units of colloquial speech.
Epidemiology
According to epidemiological surveys conducted in North America and Western Europe, 5-7% of preschool children (up to 5-6 years old) have a speech development disorder of varying severity.
Causes of the expressive alalia
In the course of many years of interdisciplinary research and in the process of streamlining the terminology used in the field of children's speech disorders, international experts have come to the conclusion that motor or expressive alalia can be diagnosed in a child when his vocabulary, as well as the ability to pronounce complex sentences and memorize words, is below the generally accepted age level, and - at the same time - these speech problems are not associated with either delayed overall development, or with the anatomical features of the speech apparatus, or with autism and autism spectrum disorder, or motor apraxia of the facial muscles, or with acquired brain damage or loss hearing.
The main causes of this pathology lie in the underdevelopment and / or intrauterine damage to the speech zones (centers) of the brain. That is, in violation of the functions of Broca's area or zone - a section of the cerebral cortex, which plays a primary role in the speech function and the formation of algorithms for using the grammatical and syntactic systems of the language. [1]
More details in the publication - Violation of the development of speech and language in a child
Risk factors
Determining the most likely risk factors for expressive alalia, experts note the possibility of a combination of various factors, including:
- teratogenic effects on the fetus of chemicals and drugs used during pregnancy;
- brain injuries and intracerebral hemorrhages during difficult or complicated childbirth;
- cerebral inflammatory processes of bacterial or viral etiology; [2]
- intrauterine and/or neonatal metabolic disorders;
- genetically determined predisposition.
Pathogenesis
Broca's area responsible for speech motility includes Brodmann's cytoarchitectonic fields (areas) 44 and 45 (pars opercularis and pars triangularis) in both hemispheres of the brain. With the left hemisphere dominant in right-handers (dextrals), Broca's area is located in the inferior frontal gyrus (inferior gyri frontalis) of the left hemisphere, immediately in front of the front part of the motor cortex (cortex motorius) and just above the Sylvian sulcus (sulcus lateralis). [3]
According to experts, motor alalia is more often detected in senestrals, that is, in left-handed children - with a dominant right hemisphere of the brain, despite the fact that the left hemisphere is responsible for language and speech in right-handers. And the pathogenesis of deviations in the development of speech function in children may be due to disproportion in the development and violation of the spatial organization of speech structures in the left and right hemispheres - with lateralization of speech function in the right hemisphere and its increased activity. [4]It is also possible to disrupt the conduction of impulses along the neuronal tract (arcuate bundle), which connects Broca's area with other areas of the brain, including Wernicke's area.
Wernicke's area is located next to Broca's area - in the upper part of the posterior temporal lobe (lobus temporalis); it is considered the center of perception and understanding of speech. Motor or expressive and impressive alalia (or sensory) is possible, and in the second case it is Wernicke's area that is affected. And with the defeat of both zones, motor-sensory alalia is detected. [5], [6]
The mechanisms of expressive alalia are also discussed in the articles:
Symptoms of the expressive alalia
Parents should keep in mind: the first signs of delayed speech development in a child are the absence of cooing (and other sounds except screaming) by two months, which is considered the initial stage of preverbal development of infants.
Common symptoms of expressive alalia include no babbling by 12 months and no simple words by 18 months.
It is necessary to suspect a violation of the development of speech functions if:
- by age two, the child is not speaking or using at least 25 words);
- by two and a half years, does not pronounce two-word phrases (noun + verb);
- does not use at least 200 words by age 3 and is unable to speak in short sentences;
- has difficulty pronouncing previously learned words, as well as adding words into sentences.
In a child with motor alalia, in addition to an insufficient vocabulary (compared to other children of the same age), there is no fluency in speech, there may be articulation defects, violations of the syllabic structure of the language and agrammatism. In addition, children with this disorder often have signs of a psychoorganic syndrome of varying severity, which are manifested by a decrease in working capacity in combination with intellectual development defects, impaired attention, and motor disinhibition. [7]
Complications and consequences
Language development disorders in early childhood can have complications and consequences for schooling and everyday social interaction in adulthood. [8]
However, according to the American Academy of Family Physicians, up to 75% of two- to three-year-old children with motor-type alalia have normal speech skills by the time they enter school. [9]
Diagnostics of the expressive alalia
Experts recognize that the diagnosis, that is, the formal assessment of expressive alalia, has many difficulties.
It is necessary to timely contact a pediatric neurologist and conduct a study of the neuropsychic sphere of the child, as well as a study of cognitive functions .
Instrumental diagnostics can be performed: CT or MRI of the brain, electroencephalography (EEG).
Differential diagnosis
It is necessary to exclude orofacial myofunctional disorders with impaired articulation, bulbar dysarthria in cerebral palsy, receptive speech disorders in autism, psychogenic mutism, mental development disorders, for which differential diagnosis is necessary.
Treatment of the expressive alalia
The treatment of a child's language development disorder is based on the work of an experienced speech therapist with him , and, if necessary, a child psychologist or psychiatrist.
And the methods of overcoming this disorder are chosen by speech therapists individually, but they are necessarily aimed at developing the so-called phonemic hearing and perception of words, their syllabic structure, understanding the lexical and grammatical structure of speech, etc. [10]
Prevention
There are no specific measures to prevent language development disorder, but risk factors for its development can be avoided.