Recently, neurological diseases are becoming more and more common. This is due to the aging of the nation, frequent head injuries. A special place among neurological pathology is occupied by sensory and gnostic disorders.
What is understood by these disorders?
Impairment of sensory and gnostic function is a malfunction in recognition of certain stimuli or objects in the brain or peripheral nerve endings. This occurs due to improperly constructed neural connections in the brain or in the presence of an obstacle that prevents nerve impulses from penetrating into it. If such a violation is observed in the cerebral cortex, then such a violation is called secondary and is classified as Gnostic (since in it, as well as in some other brain structures, all information coming from peripheral neurons is processed).
If at first peripheral nerve endings or pathways are affected, then in this case there are disorders of sensory synthesis (since the afferent branch of the spinal nerve mainly suffers, and correctly creating an electrical impulse becomes an impossible task). Since the cerebral cortex and peripheral nerve endings can perform their function only together, the disorders are considered as a single unit.
The difference between lesions of the central and peripheral link
Disorders of central genesis, as the name implies, are manifested in brain damage - the center of processing all incoming information. Brain tissue is extremely sensitive to various factors, which is why Gnostic disorders prevail in severity. Since usually all its structures are involved in the pathological process, a mental disorder may also develop. In this case, psychosensory disorders occur. Sensory disorders are the cause of damage to the peripheral link of the nervous system - receptors, as well as directly to the cranial nerve trunks. They develop much more often and usually do not require treatment (with the exception of neuropathies).
Combined disorders are most often mixed. Their cause is usually intoxication with psychotropic compounds (not necessarily drugs and alcohol) or systemic diseases of the nervous system.
Types of sensory systems of the human body
The main function assigned to the senses is the perception of stimuli coming from outside. In order to adapt to the environment, nature conceived the creation of special structures designed to perceive all information coming from outside.
Due to the fact that all impulses are different in their structure and nature, there are five groups of sensory systems - vision, hearing, smell, touch, taste. Each of them is strictly specific, has its own organs of perception, its centers in the cerebral cortex, which are responsible for processing the incoming information.
Each of these systems has its own receptors located in a specific place (not counting the skin on which the receptors are located on its entire surface). Receptors differ both in their structure and in the type of effect on them.
The disturbances in the perception of incoming stimuli are strictly specific for each system, and that is why each of them should be analyzed.
Visual agnosia
Visual disturbances are usually manifested by fuzzy vision of objects, vagueness, and they are caused by a violation of the function of the eye structures. In contrast, a violation of sensory perception lies in the defeat of the pathways (in this situation, the optic nerves) and the cortex (usually with damage to the occipital lobe of the brain). Visual agnosia is usually also accompanied by damage to long-term memory, in particular, it is associated with remembering and creating images of an object in the mind.
Sensory visual disturbance is usually accompanied by impaired perception of the color scheme of the subject. It appears in lesions of cones - receptor cells located on the retina, resulting in the development of color blindness. Violation can be characterized by a distortion of the shape of the object in the mind (knowing that an object, for example, a ball, round, a sick person sees it as oval, with growths - this condition usually develops with hallucinations, especially true ones, and in this situation refers to gnostic disorders) . Sensory and gnostic visual disturbances occur with hallucinations of various origins.
Impaired sound perception
Hearing is due to the normal functioning of the conductive system of the ear - the eardrum, the ossicles of the middle ear and the cochlea inner. Sensory disturbances (deafness) usually develop with damage or underdevelopment of the auditory ossicles (anvil malleus, stapes). If the pathology lies in the defeat of the hypothalamus (the main center of perception of all impulses from the senses), as well as in the temporal lobe of the cerebral cortex, then sensory disorders of the auditory analyzer are implied in this case. Typically, such disorders appear at an early age, which is why quite often questions are raised about children's sensory disorders.
Gnostic disorders also occur when there are changes in the temporal lobes. They are most often manifested in a disturbed perception of sound intensity (a quiet sound seems deafeningly loud and vice versa), a violation of understanding of what is heard (in parallel with the temporal lobe, the Wernicke zone is involved in the process - the center of speech perception).
Sense of smell
Sensory olfactory disorders usually develop as a result of damage to the mucous membrane of the nasal cavity (in particular, its upper third, where the peripheral nerve endings of the olfactory nerve are located). This usually occurs as a result of inhalation of pungent odors, burns of the mucous membrane due to ingestion of hot steam, and nasopharyngeal injuries. At the same time, the receptors of these endings cannot perceive aromatic molecules, which is why insensitivity to odors develops.
Violation of odor recognition occurs with brain injuries, hemorrhage in the hippocampus and limb, and also as a result of the formation of a focus of pathological impulse in these areas that appears due to the use of psychoactive substances - such as LSD, spice, and also against the background of some psychiatric diseases, accompanied by
hallucinatory syndrome (for example, with schizophrenia, some types of encephalopathy).
Sense of touch
Tactile sensitivity is due to receptors located on almost the entire surface of the skin. They are responsible for the perception of the subject and some of its characteristics (size, weight, temperature, shape). All this is carried out due to the formation of complex impulse bonds coming from all receptors simultaneously. With the defeat of the peripheral nerve link (endings and trunks), only a decrease in sensitivity develops. The image of the object itself is created in the cerebral cortex, usually in the frontal lobe and partially in the temporal lobe. A central lesion of these zones (traumatic brain injury, stroke, cerebral infarction, poisoning by some poisons) can lead to the formation of a lesion in which all neural connections will be disrupted, due to which a person will not be able to perceive and create an image of an object in his mind . Often with such disorders, due to the restructuring of the connections, the image is perceived incorrectly according to one or several criteria (round seems flat, and warm - hot or cold).
Taste agnosia
Taste buds are located mainly on the tip of the tongue, as well as on its lateral surfaces. Sensory disorders usually develop with burns of the mucous membrane of the tongue, which makes the sense of taste dull. A similar condition can also develop when they are blocked by certain substances (for example, the taste is weaker after eating cold foods or spicy seasonings). Damage to the taste nerve trunk is observed as a result of injuries of the chin muscles, as well as neuropathy or trauma to the tongue.
A violation of taste recognition usually develops after a stroke, hemorrhage in the thalamus and cerebral cortex, as well as with some neuroinfections (meningitis, encephalitis). Gnostic taste disorder (however, a perversion of taste manifests itself more) can occur in pregnant women against the background of toxicosis or gestosis (for example, a nail tastes unforgettable and a wonderful treat).
The combination of different types of sensory disorders
Often, the above sensory disorders can develop independently of each other. However, there are several types of diseases that lead to their combined development. The most obvious example of such diseases are sensory disorders in multiple sclerosis.
This disease is characterized by the development of foci of compaction of brain tissue with a predominance of connective tissue in them. A similar disorder is usually found in people older than 50-60 years, however, cases of its development are also known in fairly young people (30-35 years old).
Gnostic disorders appear in cases where such foci develop in the places where the incoming impulses are processed (i.e., in those parts of the brain where the main centers of perception are projected).
The violation of recognition and interpretation is eliminated by adequate treatment of multiple sclerosis, which was started at an early stage of the disease. If you are late with timely diagnosis, violations become chronic.
Treatment of sensory and gnostic disorders
There is no specific treatment for sensitivity disorders. All medical measures are aimed at eliminating the cause (for example, with a stroke it is recommended to limit the site of hemorrhage as soon as possible (with a hemorrhagic form) or reduce the pressure (with an ischemic stroke) to acceptable numbers . However, therapy should not be started without first consulting a neurologist and psychotherapist, since self-medication in such situations can significantly harm health.
If the cause of sensory disturbance is a burn, frostbite, then therapy should be carried out according to the severity of the injury (for mild lesions, treatment of sensory disorder can be carried out at home, and for moderate and severe ones, only in a hospital or intensive care unit). The function of the receptors will be restored during the treatment and physiological renewal of the cellular composition of the tissues of the affected area (since the receptors are mainly located in the mucous membranes or skin, and they, in turn, are tissues with high regenerative potential).