Cortical dysarthria

There are quite specific violations of speech functions, which in clinical neurology are defined as dysarthria. One of the varieties of this neurological disorder is the so-called cortical dysarthria. This is not an isolated disease, but a speech disorder, manifested with organic damage to certain areas of the cerebral cortex. According to ICD-10, the cortical dysarthria has the code R47.1, that is, it is classified in class R - to symptoms, signs and deviations from the norm, not associated with any specific diagnosis.

[1], [2], [3], [4], [5], [6]

Causes of the cortical dysarthria

The causes of cortical dysarthria (or cortical dysarthria) are pathological disorders of the cortical areas involved in the regulation of the reproduction of speech sounds.

[7], [8], [9], [10]

Risk factors

To provoke the defeat of the premortoric cortex of the frontal gyrus and cause cortical dysarthria may be craniocerebral trauma, formed neoplasias (tumors) of the brain, as well as infectious diseases: meningitis, encephalitis, tick-borne borreliosis (Lyme disease), cerebral echinococcosis.

[11], [12], [13], [14]

Pathogenesis

The pathogenesis of articulation disorders in this type of dysarthria is associated with a partial loss of neurotransmitter functions in affected areas of the cortex, which are localized in the lower frontal lobe of the brain - in the primary motor (premotor) cortex of the inferior frontal gyrus (gyrus frontalis inferior).

These sites, consisting of pyramidal neurons, receive signals from sensory systems and in response to them generate response signals and transmit subcortical nerve fibers to their motoneurons of the spinal cord, which ensures the movement of the hands and fingers, as well as all muscles providing articulation (sound formation ). Such muscles include the tyulongue, the sublingual, the shilohody, the lingopharyngeal, the lingual, the chin, the maxillofacial, and others.

When the above sections of the cerebral cortex are affected, there is a violation of the innervation of these muscles and a restriction of the mobility of the tongue and lips, making the pronunciation of sounds extremely difficult.

Cortic dysarthria is one of the symptoms of acute cerebrovascular accident (ischemic stroke), cerebral hemorrhage (hemorrhagic stroke), Charcot's disease (Lou Gehrig) or amyotrophic lateral sclerosis, Huntington's syndrome (disease), multiple sclerosis, cerebral palsy in children (cerebral palsy) .

[15], [16], [17], [18], [19]

Symptoms of the cortical dysarthria

The key symptoms of cortical dysarthria are manifested in violations of pronunciation of the majority of sounds, primarily consonants (labial, lingual, dental, stop, fricative, etc.), for articulation of which the normal functioning of the main movable articulators - tongue and lips - is especially important. There are frequent omissions or the replacement of sounds. As a result, speech becomes obscure to others.

Also, there are tempo-rhythmic disturbances in speech (lack of fluency), although there is obvious slowing due to longer pronouncing (stretching) of certain sounds, syllables and whole words. From the side it seems that it is difficult for a speaker to move his tongue and lips, and this corresponds to reality. The fact is that if the innervation of the musculature involved in the reproduction of sounds is disturbed, their articulatory structure (the correct sequence of movements of the articulation organs) does not have the necessary level of automatism. After all, in the absence of pathologies, this automatism is developed naturally in childhood.

By the way, the first signs of cortical dysarthria are expressed in the slowing of the rate of speech, the replacement or omission of sounds (upper-lingual, crevice, blasting, hissing), in the utterance of which the maximum mobility of articulatory muscles is required. And also in reducing the level of phonation, why the loudness of the sound decreases and there is a dull pronunciation "in the nose" (nasal).

Since violations in the cortex of the frontal lobes of the brain affect the functions of neurons responsible for the work of other muscle groups (in particular, the proximal parts of the upper limbs), the speech symptoms of cortical dysarthria are often accompanied by such CNS disorders as paresthesia, spasticity and stiffness of various muscles, mobility. For example, in cerebral palsy in still small children (up to 1.5-2 years old), the signs of cortical dysarthria (like any other) manifest themselves in very low voice activity. This, of course, hampers the normal development of speech.

On the features of symptoms in cerebral palsy read - Children's cerebral palsy

The consequences of cortical dysarthria affect the general condition of the central nervous system of the patient-children and cause such complications as a significant limitation of the vocabulary, a decrease in attention and memory ability, a violation of writing and reading, motor and psycho-emotional disorders.

And in adults, the consequences are often expressed in a depressed state due to communication problems and a significant decrease in verbal communication.

Diagnostics of the cortical dysarthria

According to neuropathologists, the diagnosis of cortical dysarthria is associated with certain difficulties, and a thorough examination is required to identify the true cause of speech disorders.

In addition to anamnesis and fixation of the peculiarities of articulation (which is carried out with the involvement of a speech therapist), it may be required:

• electroencephalogram (EEG) - for determining the level of nerve conduction and measuring the strength and speed of electrical signals of the brain;
• CT or MRI of the brain, head and neck - to identify areas of damage to brain structures and conductive nerve fibers;
• blood and urine tests (on them you can determine the presence of infection and inflammation);
• spinal puncture (a study of a sample of cerebrospinal fluid can detect serious infections, diseases of the central nervous system, as well as cancers of the brain or spinal cord);
• Neuropsychological testing (helps to establish the level of cognitive abilities and understanding of speech, as well as reading and writing skills).

[20], [21], [22]

Differential diagnosis

Without all of the above, differential diagnosis of this neurological disorder is not possible.

Children with cerebral palsy (as with spastic and with hemiparetic form) especially diagnose cortical dysarthria difficult, as in this disease it is not seen in its purest form: in most cases, in addition to pathological changes in the cortex of the frontal lobe of the brain are not sufficiently developed or damaged cerebellum, the structures of the medulla oblongata, extrapyramidal system fibers, etc.

Treatment of the cortical dysarthria

Organic lesions of the cerebral cortex in most cases are not amenable to treatment, and if they are congenital, then the therapeutic methods are completely powerless. In such a situation, the only way is to correct the cortical dysarthria, which is dealt with by the speech therapist.

The main task of speech therapy is to develop an articulatory apparatus. Special exercises for articulatory muscles and exercises to articulate the way sounds help reduce the severity of speech disorders and increase speech skills in light and moderate degrees of cortical dysarthria.

Read also - Violation of speech and language development in the child and Post-stroke state

Forecast

If there is such a neurological disorder as a cortical dysarthria in the clinical picture of a disease, then, according to experts, the forecast is not so simple: the cerebral cortex is too "serious" for unreasonable assumptions. Although it is comforting that this kind of speech disturbance is not fatal, although it is very uncomfortable in terms of adaptation in society.