Pseudobulbar dysarthria.

Among the diagnosed speech dysfunctions that are caused by various neurological (often neurodegenerative) disorders and manifest themselves in impaired sound reproduction, specialists highlight pseudobulbar dysarthria.

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Epidemiology

Epidemiology of pseudobulbar dysarthria: in 85% of cases, this type of speech disorder occurs as a result of ischemic stroke in patients over 50 years of age; in young people, the main cause is traumatic brain injury. Among patients with pseudobulbar palsy, 65-90% are women aged 50 to 80 years.

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Causes pseudobulbar dysarthria.

The key causes of pseudobulbar dysarthria are bilateral lesions of the nerve fibers of the corticobulbar tract (pathway), which conducts signals from the motor neurons of the cerebral cortex to the nuclei of the motor cranial nerves (glossopharyngeal, trigeminal, facial, hypoglossal), located in the bulbar region of the medulla oblongata.

Pseudobulbar dysarthria is a problem of innervation of the muscles of the articulatory apparatus, and its pathogenesis is associated with a slowdown or even cessation of the passage of nerve impulses to these muscles and their paresis (partial paralysis).

In turn, damage to nerve fibers occurs for several reasons - vascular in nature or associated with demyelination of the sheath of nerve fibers.

Neurologists attribute the following to the vascular causes of pseudobulbar dysarthria:

• bilateral cerebral infarction (a type of ischemic stroke resulting from atherothrombotic or thromboembolic damage to cerebral blood vessels);
• cerebral autosomal dominant arteriopathy with subcortical leukoencephalopathy (CADASIL syndrome), which is recognized as the most common form of hereditary progressive degeneration of smooth muscle cells in the walls of blood vessels. The pathogenesis of this syndrome is associated with mutations in the Notch 3 gene on chromosome 19.

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Risk factors

The main risk factors for the development of pseudobulbar dysarthria against the background of cerebrovascular disorders, in particular embolic stroke, are high blood pressure, atherosclerosis, infective endocarditis, obesity, old age, and in men, the use of Sildenafil (Viagra).

Loss of myelin, the protective sheath of nerve fibers, or demyelination, is the cause of pseudobulbar dysarthria in multiple sclerosis, X-linked adrenoleukodystrophy, toxic effects of organophosphorus herbicides and insecticides, and some neuroleptic drugs.

Pseudobulbar dysarthria may develop as a result of inflammation (encephalitis, meningitis, neurosyphilis), tumors or brain injuries. This neurological disorder also occurs with progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome), the epidemiology of which among Europeans does not exceed six people per 100 thousand population.

Three times less often, pseudobulbar dysarthria manifests itself as a symptom of incurable motor neuron disorders: sporadic or hereditary amyotrophic lateral sclerosis (when neurons of the motor zone of the cerebral cortex gradually die due to gene mutations), as well as pseudobulbar paralysis (with degenerative damage to the upper motor neurons). In principle, pseudobulbar syndrome is a clinical condition that, in addition to dysarthria, is manifested by dysphagia (swallowing disorder), increased gag reflex and lability (changeability) of emotional reactions.

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Symptoms pseudobulbar dysarthria.

As neurologists note, in many cases patients with pseudobulbar dysarthria themselves do not notice the first signs of the pathology, and their relatives pay attention to changes in their speech - when it becomes slurred.

The following clinical symptoms of pseudobulbar dysarthria are distinguished:

• the rate of speech is abnormally slow, speech is quiet and unclear (what is said sounds as if the person is trying to “squeeze out” the words);
• nasal vocalization (nasal pronunciation);
• the tongue is tense (spastic) and does not rotate well in the oral cavity (but its muscles do not atrophy);
• speech is monotonous, since the general spasticity of the laryngeal muscles does not allow the pitch to vary;
• spasms of the vocal cords (dysphonia) occur;
• Difficulty in simultaneous movement of the tongue and jaws causes difficulty with chewing and swallowing (dysphagia);
• increased mandibular (lower jaw) and pharyngeal reflexes;
• It takes a certain amount of effort to close the mouth, which causes salivation;
• reduced or absent ability to control facial muscles (for example, a smile often looks like a grin);
• spontaneous manifestations of abnormal affective behavior, syndrome of involuntary crying and/or laughter.

In some cases, the innervation disorder may affect the pyramidal pathways of nerve impulses, which is manifested by increased tone of other muscle groups (spastic paresis) or hyperreflexia.

Pseudobulbar dysarthria in children

Pseudobulbar dysarthria in children may be a consequence of idiopathic cerebral neuropathies caused by hereditary dysontogenesis; hereditary globoid cell or metachromatic leukodystrophy; Van Bogaert leukoencephalitis; acute encephalomyelitis; secondary post-vaccination encephalitis; Tay-Sachs disease (GM2 gangliosidosis) caused by gene mutations; brain tumors (medulloblastoma, astrocytomas, ependymomas); traumatic brain injury (including cervical spine injury received at birth); juvenile progressive pseudobulbar syndrome. Cerebral palsy is also included in the list of causes of this type of dysarthria in children, although in most cases of cerebral palsy, diffuse cortical lesions of the brain, damage to the cerebellum, etc. are observed, and not specifically to the nerve fibers of the corticobulbar tract.

The manifestation of pseudobulbar dysarthria may begin in a child with frequent choking and coughing, problems with chewing and swallowing, salivation, facial expression disorders, and later - at the age when children begin to speak - problems with sound production of varying degrees of severity are revealed.

Speech therapists recommend that parents pay attention to how actively the child's facial muscles "work", whether the child can stick out his tongue, close his lips tightly or stretch them out like a "tube", open his mouth wide, etc. It should also be borne in mind that children with pseudobulbar dysarthria have slow and poorly understood speech, and when the child tries to pronounce something, he is tense and therefore most often silent.

Due to muscle stiffness, the automaticity of articulation is not developed, and such a child speaks poorly even at the age of five or six. Moreover, pseudobulbar dysarthria in children leads not only to the lack of a sufficient vocabulary for communication, but also complicates the adequate perception of someone else's speech. The most severe degree of pseudobulbar dysarthria in childhood is anarthria, that is, complete dysfunction of the articulatory muscles.

Stages

The intensity of symptoms directly depends on the degree of damage to the nerve fibers of the corticobulbar tract: mild (III), moderate (II) or severe (I). If the mild degree involves minor articulation disorders, then as the pathology progresses over time, irreversible consequences and complications occur, associated not only with the inability to pronounce articulate sounds, but also to swallow food.

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Forms

Domestic speech therapists distinguish such forms of pseudobulbar dysarthria as spastic form of pseudobulbar dysarthria, paretic, mixed, and with mild symptoms, erased pseudobulbar dysarthria is defined.

While neurologists consider pseudobulbar dysarthria to be a spastic type of dysarthria, since the damage to nerve fibers in this pathology is bilateral and leads to increased muscle tone in the limbs and hyperreflexia.

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Diagnostics pseudobulbar dysarthria.

Diagnosis of pseudobulbar dysarthria is carried out during examination of patients by a neurologist, and the capabilities of the articulatory apparatus (after diagnosis) are assessed by a speech therapist.

Neurological examination includes examination and anamnesis. There is a set of special tests (for oral automatism reflexes), which are used to determine the functional integrity of motor neurons and the state of innervation of the articulatory muscles. To evoke reflexes characteristic of this type of dysarthria, the doctor touches the patient's lips, teeth, gums, hard palate, nose or chin with a spatula. Based on the patient's response, the specialist can assume that the dysarthria is pseudobulbar, that is, clarify the picture of the pathology.

General and biochemical blood tests are prescribed, as well as a study of cerebrospinal fluid (for which aspiration lumbar puncture is performed). Genetic analysis may be appropriate for pseudobulbar dysarthria in children.

All possibilities offered by instrumental diagnostics of neurological disorders are necessarily used. Electroencephalography (EEG) is used to assess the level of nerve conductivity of individual structures of the brain; electromyography (EMG) allows to determine the bioelectrical activity of muscle fibers and the level of their innervation.

The speed parameters of impulse transmission from motor neurons to the nuclei of motor nerves, and from them to the corresponding muscles, can be determined by specialists using electroneuromyography (ENMG), and the detection and visualization of areas of damage to conductive nerve fibers is carried out during a cranial-cerebral MRI examination.

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Differential diagnosis

Differential diagnostics allows us to distinguish pseudobulbar dysarthria from bulbar, cortical or extrapyramidal dysarthria, as well as differentiate it from myasthenia, progressive muscular atrophy, cranial polyneuritis, etc.

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Treatment pseudobulbar dysarthria.

It is necessary to contact a neurologist and speech therapist as soon as possible, since it is possible to help correct articulation in mild and moderate pseudobulbar dysarthria, and in children with this syndrome, to master speech skills with the help of targeted development of articulatory motor skills. Medication treatment of pseudobulbar dysarthria, which would restore neurons damaged due to gene mutations or autoimmune pathologies and improve the innervation of the muscles of the articulatory apparatus, is not yet possible.

Pseudobulbar dysarthria in both children and adults (including those who have had a stroke) should be corrected by a qualified speech therapist. The specialist evaluates the degree of speech dysfunction in each patient and – on an individual basis in writing – draws up a working program for the correction of pseudobulbar dysarthria.

This is a lesson plan that includes special exercises (to normalize the tone of the articulatory muscles, breathing); practicing correct phonation; developing the articulatory structure of sounds, etc. In working with children, special attention is paid to the development of vocabulary, the formation of grammatical skills and the assimilation of norms of word usage. This creates the foundation for mastering reading and writing at the beginning of school and preventing such a complication as general speech underdevelopment. Therefore, the active participation of parents in the home reinforcement of the skills acquired by the child in classes with a speech therapist is a prerequisite in the fight against the manifestation of dysarthria.

Prevention

In neurology, the prevention of such a speech disorder as pseudobulbar dysarthria, which occurs in a number of neurodegenerative pathologies, as well as due to brain tumors, injuries, cerebrovascular problems, etc., is not considered.

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Forecast

Obviously, due to the impossibility of preventing the cause of this disorder. And the prognosis depends on the cause, which, with the progression of the underlying disease, can be disappointing...

It should be borne in mind that Group IB disability is given in the case of partial or complete loss of speech (aphasia) after strokes, injuries and tumor diseases of the brain, as well as in certain mental illnesses. Official information (with a list of pathologies and conditions) is contained in the order of the Ministry of Health of Ukraine No. 561 (dated September 5, 2011) "On approval of the Instruction on establishing disability groups."

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