Speech is the most important component of a child’s mental development, the formation of which occurs in the first years of life [1]. For a child, it is the most important means of communication with the outside world, the basis for obtaining information for the development of cognitive activity and thinking.
The communicative function of speech contributes to the development of communication skills, which is of great importance for the formation of adaptive behavior, the emotional-volitional sphere and the personality of the child. The cognitive function of speech is closely related to the communicative function. The regulatory function of speech develops by the age of 4-5 years, when the child’s semantic side of speech is sufficiently developed. The formation of this function is closely related to the development of internal speech, regulation and control of behavior and intellectual activity.
Development of speech skills is normal
For timely diagnosis of speech disorders in children, it is necessary to take into account the patterns of normal speech development. Children pronounce their first words by the end of the 1st year of life, but they begin to train their speech apparatus much earlier, already from the first months of life, so the age of up to one year is a preparatory period in the development of speech. The sequence in the development of pre-speech reactions is as follows: hooting, humming - 1.5-3 months; “pipe” (chains of different sounds) - 4-6 months; babbling - 6-7 months; babbling words and modulated babbling - 8-11 months.
In the 1st year of life, the child’s speech apparatus is preparing to pronounce sounds. The listed speech reactions are a kind of game for the baby and give the child pleasure; for many minutes he can repeat the same sound, thus training in the articulation of speech sounds. At the same time, the active formation of speech understanding occurs.
An important indicator of speech development up to one and a half to two years is not so much the pronunciation itself, but the understanding of addressed speech (receptive speech). The child must listen carefully and with interest to adults, understand spoken speech well, recognize the names of many objects, and follow simple everyday requests and instructions. In the 2nd year of life, words and sound combinations already become a means of verbal communication, i.e. expressive speech is formed.
Main indicators of normal speech development from 1 year to 4 years:
- appearance of clear, meaningful speech (words) - 9-18 months;
- at first (up to 1.5 years) the child mainly learns to understand speech, and from 1.5-2 years he quickly develops active speech and his vocabulary grows. The number of words that the baby understands (passive vocabulary) is still greater than those that he can pronounce (active vocabulary);
- the appearance of phrases of two words - 1.5-2 years, of three words - 2-2.5 years, of 4 or more words - 3-4 years;
- volume of active vocabulary: by the age of 1.5 years, children pronounce 5-20 words; 2 years - up to 150-300 words; 3 years - up to 800-1000 words; 4 years - up to 2000 words.
Disorders of speech development affect the overall development of children’s personality, their intellectual development and behavior, and make it difficult to learn and communicate with others [1–3].
Specific language development disorders (SDLDs) include disorders in which normal language development is affected in the early stages. In ICD-10 [4], these include developmental disorders of expressive language (F 80.1) and receptive language (F 80.2). In this case, disturbances appear without a previous period of normal speech development. SRDD is the most common mental development disorder; its frequency in the pediatric population is 5–10% [2, 5]. Let's consider the main types of speech development disorders.
Main forms and causes of development of speech disorders
Alalia
(according to modern international terminology “
dysphasia
” or “
developmental dysphasia
”) is a systemic underdevelopment of speech, it is based on an insufficient level of development of the speech centers of the cerebral cortex, which can be congenital or acquired in the early stages of ontogenesis, in the pre-speech period. At the same time, in children, expressive speech is characterized primarily by significant deviations, while speech understanding may vary, but, in general, it is much better developed [2, 3]. The most common variants (expressive and mixed expressive-receptive disorders) are manifested by a significant delay in the development of expressive speech compared to the development of understanding.
In modern literature, both terms (DSRD and “developmental dysphasia”) are used. But “developmental dysphasia” is considered a more accurate formulation of the diagnosis, since this term reflects both the neurological and developmental-age aspects of this disorder [3, 6].
Complete or partial loss of speech caused by local lesions of the speech areas of the cerebral cortex is called aphasia
. Aphasia is the collapse of already formed speech functions, so this diagnosis is made only after 3-4 years. With aphasia, there is a complete or partial loss of the ability to speak or understand spoken speech.
Dysarthria
- violation of the sound-pronunciation aspect of speech as a result of disruption of the innervation of the speech muscles. Depending on the location of the lesion in the central nervous system, several variants of dysarthria are distinguished: pseudobulbar, bulbar, subcortical, cerebellar.
Speech formation is an individual process that depends on many factors. The decisive period is from the 1st year of life to 3-5 years, when the central nervous system and its functions intensively develop. At the same time, the child’s speech is formed under the stimulating influence of the speech of adults and depends to a great extent on sufficient speech practice, a normal speech environment, upbringing and training.
The causes of delays in speech development may be perinatal lesions of the central nervous system, dysfunction of the articulatory apparatus, damage to the organ of hearing, a general lag in the mental development of the child, the influence of heredity and unfavorable social factors. Difficulties in mastering speech are also found in children with retarded physical development, those who suffered serious illnesses at an early age, those who are weakened, or who receive malnutrition.
Hearing impairment is a common cause of isolated speech delay [7]. Even moderate and gradually developing hearing loss can lead to delays in speech development. Signs of hearing loss in a baby include a lack of response to sound signals and an inability to imitate sounds, while in an older child there is excessive use of gestures and close observation of the movements of the lips of speaking people. However, the assessment of hearing based on the study of behavioral reactions is subjective. Therefore, if partial or complete hearing loss is suspected in a child with isolated speech delay, an audiological examination is indicated. The method of recording auditory evoked potentials also provides reliable results.
The rate of delay in speech development is due to a lack of stimulation of speech development, the influence of unfavorable intrafamily factors (insufficient communication and education). The social environment stimulates speech development and provides a speech pattern. In families with poor speech impulses, children begin to speak late and speak little. A delay in their speech development may be accompanied by a delay in other areas of development, while their natural abilities are normal.
Delayed speech development in a child may also be caused by autism [8] or general mental retardation. In these cases, an in-depth examination by a child psychiatrist is indicated. In developmental dysphasia, the primary deficit is speech impairment, and intellectual disability and limited knowledge observed in patients at different age periods are secondary. It is this feature that distinguishes patients with dysphasia from children with mental retardation, which is characterized by incomplete formation of all higher mental functions and intellectual abilities.
Motor alalia (dysphasia).
The cause of motor alalia is a dysfunction of the speech motor analyzer (motor center of speech). The child has difficulty organizing speech movements and their coordination, therefore speech development is delayed [9]. Speech understanding is not impaired. Independent speech either does not develop for a long time or remains at the level of individual sounds and words. Parents, noting silence, characterize children as understanding spoken speech, but not wanting to speak. Instead of speech, children tend to use facial expressions and gestures, especially in emotionally charged situations. The first words and phrases appear late. Parents note that, in addition to speech delays, in general, children develop normally. As their vocabulary increases, children's difficulties in mastering word structure become more noticeable. Speech is slow, impoverished, vocabulary is limited to everyday topics. There are many slips of the tongue (paraphasias), permutations, and perseverations in speech. Growing up, children understand these mistakes and try to correct them [9].
Sensory alalia (dysphasia). This form of delayed speech development is based on disorders of speech understanding, which is associated with dysfunction of the speech-hearing analyzer (sensory speech center). This leads to disorders in the analysis and synthesis of speech signals, as a result of which connections are not formed between the sound image of a word and the object or action it denotes. The degree of underdevelopment of the speech-hearing analyzer can be different. In more severe cases, the child does not understand the speech of others at all, treats it as noise devoid of meaning, and does not even react to his own name. In other cases, he understands individual words, but loses them against the background of a detailed statement. When addressed to him, he does not catch all words and their shades, so he may react to them incorrectly. Often children look into the face of the speaker, which helps improve speech understanding due to reinforcement from the visual analyzer - “reading from the face.” Sometimes a child understands only one person—the mother, the teacher [9].
When pronouncing words, numerous errors in stress, sound substitutions, and distortions are made, the nature of which often changes. The child learns new words and phrases slowly. His statements are imprecise and difficult to understand. He is not critical of his own speech. There are incoherent repetitions of all words known to the child (logorrhea), repetitions of words and phrases (echolalia), while the words are not comprehended and not remembered. In general, the speech of a child with sensory alalia can be characterized as increased speech activity against the background of impaired understanding of the speech of others and insufficient control over one’s own speech [9].
Sensory alalia in its pure form is much less common than motor alalia; sensory alalia accompanies motor alalia much more often. In these cases we speak of motor alalia with a sensory component. The existence of mixed forms of alalia indicates a close functional connection between the speech-motor and speech-auditory analyzers. A thorough examination of a child with alalia makes it possible to clarify the nature of the disorders and determine the optimal approaches to their correction.
Neurobiological factors in the pathogenesis of speech development disorders
Perinatal pathology of the central nervous system plays an important role in the formation of speech disorders in children. It is in the perinatal period that the most significant events occur that have a direct and indirect impact on the processes of the structural and functional organization of the central nervous system. Taking this into account, it is advisable to identify risk groups for disorders of psycho-speech development already in the 1st year of life [10]. The high-risk group should include children in whom, in the first 3 months of life, as a result of a clinical and instrumental examination, structural changes in the central nervous system were identified, premature babies (especially with extremely low body weight), children with disorders of the auditory and visual analyzers, insufficiency of the functions of cranial nerves (in particular, V, VII, IX, X, XII), children with delayed reduction of unconditioned automatisms, long-lasting disorders of muscle tone [10].
In premature newborns, especially those with a short gestation period, an important period of development of the central nervous system (interneuronal organization and intensive myelination) occurs not in utero, but in difficult conditions of postnatal adaptation. The duration of this period can vary from 2-3 weeks to 2-3 months, and it is often accompanied by the development of various infectious and somatic complications. This may serve as an additional factor causing disturbances in psychomotor and speech development in immature and premature children. Hearing impairment, one of the main consequences of prematurity, also plays a negative role [10, 11]. Studies have shown that approximately half of very premature children have delayed speech development, and at school age - learning difficulties, problems with reading and writing, concentration and behavior control [12].
In recent years, the role of genetic factors in the formation of speech development disorders has attracted attention. The role of hereditary predisposition is confirmed by the high frequency of intrafamilial occurrence of speech development disorders [2]. Among the genes that can determine delayed speech development, FOXP 2
on chromosome 7q31.
It is believed that FOXP2
simultaneously controls both the acquisition and application of grammatical language rules and speech motor skills - movements of the muscles of the tongue, lips, and larynx.
There are familial and sporadic cases of expressive language disorders caused by mutations in the FOXP2
[13].
The number of genes that can determine delayed speech development also includes FOXP 1
(on chromosome 3p14),
CNTNAP 2
(7q36),
ATP 2 C 2
(16q24),
CMIP
(16q24)
SETBP 1
(18q12.3),
NRXN 1
(2p13.3),
TM 4 SF 20
(2q36.3) ,
SRPX 2
(Xq22.1),
KIAA 0319
(6p22.2) [13, 14]. Attention should be paid to the multiple influences of these genes on the processes of formation of various brain structures and functions, which reflects the close connection in the formation of speech and other higher mental functions. Identification of genetic risk factors is important because it will potentially allow us to identify the biological pathways and brain mechanisms that are involved in the processes of language acquisition and play a key role in the etiology of speech development disorders. In addition, studying the identified genetic factors will provide an opportunity to unravel the complex relationships between language impairment and other related developmental disorders.
Thus, speech development disorders in children may be based on neurobiological factors, including early organic damage to the central nervous system due to perinatal pathology and hereditary predisposition, which can be combined in some patients.
Age dynamics and outcomes of speech development disorders
By school age, the outcomes of developmental dysphasia remain insufficiently studied. C. Miniscalco et al. [15] conducted a longitudinal study that included 25 children (18 boys, 7 girls) with moderate or severe manifestations of dysphasia at the age of 30 months. By the age of 6-7 years in this group of children, 6 people had no neuropsychic disorders, while the rest were diagnosed with attention deficit hyperactivity disorder (ADHD) (11 children), dyslexia (4), high-functioning autism (5) , developmental dyspraxia (7), borderline level of intellectual development (6), mental retardation (2) (the sum exceeds 25, since in some cases the children had several diagnoses).
We conducted [16] a retrospective study of the neuropsychological development of children with developmental dysphasia and its outcomes by primary school age. We examined 110 children, 87 boys and 23 girls, with a diagnosis of developmental dysphasia (or expressive speech development disorder - F80.1 according to ICD-10 [4]) established at the age of 3-4 years and 1-2 levels of general speech underdevelopment (GSD). ). All of them underwent repeated clinical, neurological and psychological examinations on an outpatient basis at the age of 7-9 years. Children whose speech development delay was caused by hearing loss, severe mental retardation, severe somatic or congenital endocrine pathology, malnutrition, as well as the influence of unfavorable social factors (insufficient communication and education) were excluded from the study group. The absence of any psychoneurological abnormalities by the age of 7-9 was established in only 8 (7.3%) people. Most often, the following pathological conditions were diagnosed, accompanied by significant difficulties in school learning: ADHD - in 39 (35.5%) patients, disorders of the development of written speech (dyslexia and dysgraphia) - in 15 (13.6%), dyslalia with OHP 3- 1st level - in 13 (11.8%).
A number of patients were under dynamic supervision of a neurologist with diagnoses such as cerebrasthenic syndrome - 8 (7.3%), autonomic dysfunction syndrome with frequent headaches - 6 (5.5%), chronic motor tics - 6 (5.5%) , nocturnal enuresis - 3 (2.7%). In 7 (6.3%) patients with an initial diagnosis of dysphasia, autistic disorders were confirmed during further follow-up, including childhood autism (2 children) and high-functioning autism (5 children). In some cases, patients continued to be observed with diagnoses such as mental retardation (mild mental retardation) (3), epilepsy (1), schizotypal disorder (1).
Thus, manifestations of developmental dysphasia at an early age can serve as harbingers of a number of psychoneurological disorders, the formation of the clinical picture of which passes through the OPD stage: dyslexia and dysgraphia, ADHD, autism [16]. In other cases, developmental dysphasia may be caused by perinatal damage to the central nervous system, the consequences of which are not completely overcome by primary school age, even with positive dynamics in speech development (dyslalia with OHP level 3, cerebrasthenic syndrome, autonomic dysfunction syndrome with frequent headaches, chronic motor tics , nocturnal enuresis) [16].
Early signs of trouble in speech formation
Speech acquisition is one of the main indicators of a child’s mental development. Children who do not try to speak at 2-2.5 years should be a cause for concern. However, parents may notice certain prerequisites for problems in speech development earlier [1]. In the first year of life, one should be alarmed by the absence or weak expression at appropriate times of humming, babbling, first words, reaction to adult speech and interest in it; at 1 year - the child does not understand frequently used words and does not imitate speech sounds, does not respond to addressed speech, and resorts only to crying to attract attention to himself; in the 2nd year - lack of interest in speech activity, growth of passive and active vocabulary, the appearance of phrases, inability to understand the simplest questions and show an image in a picture.
At 3-4 years of life, the following manifestations should cause high alertness: the child does not turn to adults with questions or for help, does not use speech. Vocabulary is limited; he cannot name objects known to him. Doesn't answer simple questions. The child’s speech is incomprehensible to others and he tries to supplement it with gestures, or shows indifference to whether other people understand him. The child has no desire to repeat words and phrases after adults, or he does it reluctantly.
As a screening method for identifying delays in speech development, parents can be asked a number of special questions to which the answers are “yes” or “no” (Tables 1 and 2). All questions are divided into two groups and characterize the formation of impressive and expressive speech: 1. Speech perception and hearing (hereinafter referred to as speech understanding), 2. Vocal and expressive reactions (hereinafter referred to as speech expressive reactions). Interpretation: all answers are “yes”: the child’s speech develops normally, hearing is not impaired; 1-2 answers “no”: you need to consult a specialist (doctor, speech therapist), and also have your hearing examined.
Table 1. Screening assessment of pre-speech development in children of the 1st year of life
Table 2. Screening assessment of speech development in children from the 2nd year of life to 5 years
Treatment
Speech underdevelopment due to dysphasia (alalia) is quite profound and requires not only changes in educational conditions, but also the help of specialists in the form of consultations or regular classes. Correction takes a long time and requires a lot of effort. If special measures are not taken, the process of speech acquisition will not only be delayed in time, but will begin to take on a distorted character.
The main directions of correction for speech formation disorders in children are complex interventions: speech therapy, psychological-pedagogical, psychotherapeutic assistance to the child and his family, as well as drug treatment (in the form of repeated courses of nootropic drugs). Of particular importance when organizing assistance to such children is the continuity of work with children by specialists in various fields (doctors, speech therapists, psychologists, teachers). Planning and implementation of corrective measures should be carried out according to individual plans for each child.
Timely use of nootropic drugs contributes to the most complete correction of speech development disorders. In groups of children with developmental dysphasia who received a course of monotherapy with nootropic drugs for 2 months, a significant improvement in indicators of expressive and impressive speech, as well as speech attention, was achieved [17]. The volume of the active vocabulary increased by 3.1-3.5 times, the number of spoken phrases - by 3.3-5 times, while in the control group - only by 1.5 times. It should be noted that the influence of nootropic drugs was multidirectional, helping not only to overcome speech development disorders in children, but also difficulties in the cognitive sphere, contacts with others, and social adaptation. According to the results of a parent survey, children showed a decrease in cerebrasthenic and psychosomatic disorders, motor clumsiness, hyperactivity, and improved attention, emotional control and behavioral characteristics [17].
A promising direction in drug therapy for dysphasia is the use of peptidergic nootropic drugs, in particular the domestic drug Cortexin. This drug contains a complex of water-soluble polypeptide fractions with a molecular weight of no more than 10,000 Da, easily penetrates the blood-brain barrier, and has a multimodal tissue-specific effect on the central nervous system. Studies have proven the neuroprotective effect of the drug - influence on the cascade regulation of apoptosis, prevention of the formation of free radicals and lipid peroxidation products, restoration of ATP levels in mitochondria [18, 19]. In the treatment of dysphasia, the most important aspects of its action are its positive effect on the mechanisms of neuroplasticity and neuroreparation (activates neuronal peptides and neurotrophic factors; optimizes the balance of metabolism of excitatory and inhibitory amino acids, dopamine, serotonin; has a GABAergic effect; helps improve the bioelectrical activity of the brain) [ 20, 21].
L.S. Chutko et al. [22] studied the effectiveness of Cortexin in the treatment of SRRR. 75 children were examined, divided into two subgroups. For the treatment of children in the main group (48 people), Cortexin was used intramuscularly at a dose of 0.5 mg/kg for children weighing up to 20 kg and 10 mg for children weighing 20 kg or more. The treatment course consisted of 10 injections once every other day in the morning. The duration of the course was 20 days. In the comparison group (27 patients), encephabol was administered orally in the form of a suspension (containing 20 mg of the active substance in 1 ml) at a dosage of 12-15 mg/kg/day in two doses (morning and afternoon) for 30 days. In the subgroup of children with developmental disorders of predominantly expressive speech, positive dynamics after treatment with Cortexin were observed in 19 (65.5%) cases. After treatment, the children began to use their vocabulary more actively, the grammatical structure of speech improved, and there was an increase in the number of syllables in repeated phrases. In the subgroup with a developmental disorder of predominantly receptive speech, positive dynamics were noted in 4 (57.1%) cases; children from this group showed a noticeable improvement in their understanding of addressed speech. After therapy with Cortexin, positive dynamics of EEG parameters were recorded in patients. In general, the results of the study indicate the high effectiveness of Cortexin in the treatment of SRRD with a predominance of both expressive and expressive-expressive speech disorders, which makes it possible to recommend it in the complex rehabilitation of children with speech development disorders [22].
I.I. Ogorodova et al. [23] assessed the effectiveness of correction of speech disorders in 93 children aged 3 to 7 years, among whom 12.9% had level 2 SLD, 87.1% of children had level 3 SLD. The majority of children (85%) also had ADHD, cerebrasthenic syndrome, and emotional-volitional disorders. Patients of the main group ( n
=48) as part of complex therapy for 10 days received intramuscular injections of cortexin at a dose of 0.5 mg/kg/day for body weights up to 20 kg and 10 mg for body weights over 20 kg.
Indicators of psychospeech development improved in 81.5% ( n
=39) of children from the group treated with Cortexin, compared to the control group - 46.6% (
n
=21). With Cortexin therapy, a more stable recovery of speech functions (sound pronunciation, vocabulary, grammar) and regression of neurological symptoms were noted.
When carrying out complex correction, positive dynamics can be observed in children with dysphasia; they consistently move from one level of speech development to another, higher one, and acquire new speech skills and abilities. It is well known that correctional assistance provided during the sensitive age period for speech formation, from 2.5 to 5 years, is effective, when speech function is actively developing. Therefore, it should be noted that the earlier problems in the development of a child’s speech are noticed and specialists begin to work with him, the better the results achieved will be, since the reserve capabilities of the child’s developing brain are highest in the first years of life.
Delayed speech development (SDD)
To correctly understand what signs indicate a delay in speech development, it is necessary to know the main stages and conventional norms of speech development in young children.
The birth of a child is marked by a cry, which is the baby’s first speech reaction. A child’s cry is realized through the participation of the vocal, articulatory and respiratory sections of the speech apparatus. The time at which the cry appears (normally in the first minute), its volume and sound can tell a neonatologist a lot about the condition of the newborn. The first year of life is the preparatory (pre-speech) period, during which the child goes through the following stages:
- walking (from 2-3 months);
- babbling (from 5-6 months);
- babbling words (from 8-10 months);
- first words (at 10-12 months).
Normally, at 1 year of age, a child’s active vocabulary contains approximately 10 words consisting of repeated open syllables (ma-ma, pa-pa, ba-ba, dy-dya, etc.); in the passive dictionary - about 200 words (usually the names of everyday objects and actions). Until a certain time, the passive vocabulary (the number of words whose meaning the child understands) greatly exceeds the active vocabulary (the number of spoken words).
At approximately 1.6 - 1.8 months. the so-called “lexical explosion” begins, when words from the child’s passive vocabulary suddenly flow into the active vocabulary. For some children, the period of passive speech can last up to 2 years, but in general their speech and mental development proceeds normally. The transition to active speech in such children often occurs suddenly and soon they not only catch up with their peers who spoke early, but also surpass them in speech development.
Researchers believe that the transition to phrasal speech is possible when a child has at least 40–60 words in his active vocabulary. Therefore, by the age of 2, simple two-word sentences appear in the child’s speech, and the active vocabulary grows to 50-100 words. By the age of 2.5 years, the child begins to construct detailed sentences of 3-4 words.
In the period from 3 to 4 years, the child masters some grammatical forms, speaks in sentences united by meaning (coherent speech is formed); actively uses pronouns, adjectives, adverbs; masters grammatical categories (changing words according to numbers and genders). Vocabulary increases from 500-800 words at 3 years to 1000-1500 words at 4 years.
Experts allow deviations from the normative framework in terms of speech development by 2-3 months in girls, and by 4-5 months in boys. Only a specialist (pediatrician, pediatric neurologist, speech therapist) who has the opportunity to observe the child over time can correctly assess whether the delay in the appearance of active speech is a delay in speech development or an individual characteristic.
