Pathological reflexes of the upper and lower extremities. Reflexes of oral automaticity.

Pathological reflexes (PR) are a group of reflexes that appear at the moment of damage to the main neuron. The neuron is localized in the center of the human brain, the neural pathways that lead to the spinal cord, as well as sections of the cranial nerves.

These structures are responsible for motor acts. The consequence of their defeats is the formation of new connections between sensations (physical) and the body's reactions to stimuli.

It turns out that pathological reflexes are manifested by nonspecific motor actions that occur as a result of exposure to irritating factors from the outside.

PR can only appear if the pyramidal tracts are damaged or disrupted. Most often, the cause of this is various neurological disorders and underdevelopment of the central nervous system in infants.

Pathological foot reflexes and oral automatism attract the most attention today. Although, besides them, there are a huge number of other types of human reflexes.

The concept of pathological reflex

When the main neuron of the brain or neural pathways are damaged, pathological reflexes occur. They are manifested by new connections between external stimuli and the body’s response to them, which cannot be called the norm. This means that the human body reacts inadequately to physical contact, compared to a normal person without pathologies.

Such reflexes indicate any mental or neurological diseases in a person. In children, many reflexes are considered normal (extensor-plantar, grasping, sucking), while in adults the same ones are considered a pathology. At the age of two years, all reflexes are caused by an immature nervous system. Both conditioned and unconditioned reflexes can be pathological. The former manifest themselves as an inadequate response to a stimulus, fixed in memory in the past. The latter are biologically unusual for a given age or situation.

Needs and behaviors

Congenital species:

• Unconditioned reflexes. Instincts:
  Vital: food, regulation of forces, etc.
• Role-playing, zoosocial: gender, parental, child, territorial.
• Self-development, ideal: freedom and overcoming, play, research, imitation.
• Approximate.
• Imprinting.

Purchased, individual:

• Conditioned reflexes.
• Alternation of sleep and wakefulness.
• Behavior formed through learning:
  Voluntary memory and attention.
• Walking, speech, household, sports, professional skills.

Exploratory behavior –> formation of a spatio-temporal image of the surrounding world.

• Orienting reflex.
• Need for information –> exploratory behavior: formation of an image of the surrounding world.

Causes

Pathological reflexes can result from brain lesions and pathologies of the central nervous system, such as:

• damage to the cerebral cortex by infections, spinal cord diseases, tumors;
• hypoxia - brain functions are not performed due to lack of oxygen;
• stroke – damage to the blood vessels of the brain;
• Cerebral palsy (cerebral palsy) is a congenital pathology in which the reflexes of newborns do not fade over time, but develop;
• hypertension;
• paralysis;
• coma state;
• consequences of injuries.

Any diseases of the nervous system, damage to neural connections, or diseases of the brain can cause incorrect, unhealthy reflexes.

Pathophysiology

This abnormal phenomenon is considered the first sign of deformation of the central motor neuron system. It includes axons and motor neurons of the precentral gyrus of the GM cortex. The axons make up the corticospinal tract and go to the motor neurons of the SC (anterior horns).

Inhibitory impulses are provided by fibers of the corticospinal tract. Thanks to inhibitory impulses, the manifestation of spinal manifestations, which are ontogenetically much older, is stopped.

Inhibitory impulses stop flowing to the motor neurons of the SC if there is damage to the central motor neuron system. It is against this background that the anomalous Bekhterev-Mendel reflex is formed.

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Classification of pathological reflexes

Pathological reflexes are divided into the following groups:

• Reflexes of the upper limbs. This group includes pathological carpal reflexes, an unhealthy response to external stimuli of the upper extremities. May manifest as involuntary grasping and holding of an object. They occur when the skin of the palms at the base of the fingers is irritated.
• Reflexes of the lower extremities. These include pathological foot reflexes, reactions to tapping with a hammer in the form of flexion or extension of the phalanges of the toes, and flexion of the foot.
• Reflexes of the oral muscles are pathological contractions of the facial muscles.

Bekhterev's contribution

There is no doubt about the contribution of V.M. Bekhterev in the discovery and description of this pathological manifestation. At the beginning of the twentieth century, the great Russian neurologist, in his article “On the carpal-phalangeal reflex,” described a pathological manifestation on the upper limb. This phenomenon manifests itself in the fact that the digital phalanges bend in the event of mechanical irritation on the back side of the actual area of ​​the body. The impact is carried out using a special neurological hammer.

The essence of the manifestation is that irritation is transmitted from the ligaments covering the back of the actual zone to the flexors of the digital phalanges. The reflex arc is located in the area of ​​the lower cervical roots and the 1st thoracic root.

The detection of this manifestation may indicate that at levels located above the cervical part of the SC, there is a serious lesion of the central motor neuron.

Foot reflexes

Extensor reflexes of the foot are an early manifestation of damage to the nervous system. The pathological Babinski reflex is most often tested in neurology. It is a sign of upper motor neuron syndrome. Belongs to the group of reflexes of the lower extremities. It manifests itself as follows: a stroking movement along the outer edge of the foot leads to extension of the big toe. May be accompanied by fanning out all the toes. In the absence of pathology, such irritation of the foot leads to involuntary flexion of the big toe or all the toes. Movements should be light and not cause pain. The reason for the formation of the Babinski reflex is the slow conduction of stimulation along the motor channels and impaired excitation of segments of the spinal cord. In children under one and a half years of age, the manifestation of the Babinski reflex is considered normal; then, with the formation of gait and vertical body position, it should disappear.

A similar effect can occur with other effects on receptors:

• Oppenheim reflex - extension of the finger occurs when pressing and moving from top to bottom with the thumb in the area of ​​the tibia;
• Gordon's reflex - when the calf muscle is compressed;
• Schaeffer reflex - when the Achilles tendon is compressed.

Pathological flexion reflexes of the foot:

• Rossolimo reflex - when exposed to abrupt blows of the hammer or fingertips on the inner surface of the phalanges, rapid flexion of the II-V toes occurs;
• ankylosing spondylitis reflex - the same reaction occurs when lightly tapping the outer surface of the foot in the area of ​​​​the metatarsal bones;
• Zhukovsky reflex - manifests itself when struck in the center of the foot, at the base of the toes.

Pathological reactions of unconditioned reflexes

In addition to pathological reflexes of the upper, lower extremities and oral muscles, pathological reactions of unconditioned reflexes are also distinguished:

1. Reflexes are perverted . Such reflexes provoke the formation of a dominant focus in the area of ​​the main center (for example, bending the arm). When the tendons are stretched, at the moment of irritation due to the dominant focus, the limb will not flex, but extend. This pathology can be triggered by intoxication with tetanus toxins, injury to nerve endings and pressure on the nerve fibers of scars.
2. Reflex contractures . They appear in the area where the dominant focus has stagnated. Nerve impulses that will be transmitted through the joints from the area of ​​injury will first create and later strengthen this focus in the spinal cord itself. As a result of this process, strong flexion of the injured limb occurs, which, if prolonged, causes severe pain and discomfort.
3. Reflex paralysis . They appear due to the slowing down of motor neurons in the impulses of more sensitive neurons. An example is the formation of scars in the area of ​​​​sensitive nerve endings. With strong pressure and pinching of the nerve, paralysis of the limbs and body can develop.
4. Reflexes exhibiting nonspecific reflex projection . One of the striking examples of this type of reflex is Babinski’s symptom. It involves bending the toes when a stimulus is applied to the area from the end of the heel to the beginning of the toes.

Oral automaticity reflexes

Oral automatism is the reaction of the oral muscles to a stimulus, manifested by their involuntary movement. Pathological reflexes of this kind are observed in the following manifestations:

• The nasolabial reflex, which occurs when the base of the nose is tapped with a hammer, is manifested by stretching the lips. The same effect can occur when approaching the mouth (distance-oral reflex) or when lightly hitting the lower or upper lip - oral reflex.
• Palmomental reflex, or Marinescu-Radovic reflex. The stroke movements in the area of ​​the thumb from the side of the palm cause a reaction of the facial muscles and cause the chin to move.

Such reactions are considered normal only for infants; their presence in adults is pathological.

Synkinesis and defensive reflexes

Synkinesis are reflexes characterized by paired movements of the limbs. Pathological reflexes of this kind include:

• global synkinesia (when the arm is bent, the leg is extended or vice versa);
• imitation: involuntary repetition of movements of an unhealthy (paralyzed) limb after the movements of a healthy one;
• coordinator: spontaneous movements of an unhealthy limb.

Synkinesis automatically occurs during active movements. For example, when moving a healthy arm or leg, a spontaneous muscle contraction occurs in a paralyzed limb, a flexion movement of the arm occurs, and an extension movement of the legs occurs.

Protective reflexes arise when a paralyzed limb is irritated and are manifested by its involuntary movement. An irritant can be, for example, a needle prick. Such reactions are also called spinal automatisms. Protective reflexes include the Marie-Foy-Bekhtereva symptom - flexion of the toes leads to involuntary flexion of the leg at the knee and hip joint.

Tonic reflexes

Normally, tonic reflexes appear in children from birth to three months. Their continued manifestation even in the fifth month of life may indicate that the child has cerebral palsy. With cerebral palsy, congenital motor automatisms do not fade away, but continue to develop. These include pathological tonic reflexes:

• Labyrinthine tonic reflex. It is checked in two positions - on the back and on the stomach - and manifests itself depending on the location of the child’s head in space. In children with cerebral palsy, it is expressed in increased tone of the extensor muscles when lying on the back and flexor muscles when the child lies on the stomach.
• Symmetrical cervical tonic reflex. In cerebral palsy, it is manifested by the influence of head movements on the tone of the muscles of the limbs.
• Asymmetrical cervical tonic reflex. It manifests itself as increased muscle tone in the limbs when turning the head to the side. On the side where the face is turned, the extensor muscles are activated, and on the side of the back of the head, the flexor muscles.

With cerebral palsy, a combination of tonic reflexes is possible, which reflects the severity of the disease.

Babinski reflex

The main extensor reflex is the Babinski foot extensor reflex. It is caused by streak irritation, carried out by pressing the blunt end of an injection needle on the outer edge of the plantar surface of the foot in the direction from the heel to the toes (Fig. 1.4.7).

Normally, in this case, the plantar reflex is evoked (flexion of all toes). When the central motor neuron (corticospinal part of the pyramidal tract, projection motor cortex) is damaged, extension of the thumb occurs. This reflex is of very great clinical importance. There are a number of modifications of the methods for inducing it: squeezing the Achilles tendon (Schaeffer reflex), squeezing the calf muscle in its distal section (Gordon reflex), pressing the thumb on the anterior inner surface of the shin with sliding down the entire shin (Oppenheim reflex), etc.

Tendon reflexes

Tendon reflexes are normally caused by hitting the tendon with a hammer. They are divided into several types:

• Biceps tendon reflex. In response to a hammer blow on it, the arm bends at the elbow joint.
• Triceps tendon reflex. The arm is bent at the elbow joint, and upon impact, extension occurs.
• Knee reflex. The blow falls on the quadriceps femoris muscle, under the kneecap. The result is extension of the leg at the knee joint.

Pathological tendon reflexes manifest themselves in the absence of a reaction to hammer blows. They can occur with paralysis, coma, or spinal cord injuries.

General information about manifestation

The Mendel-Bekhterev reflex, in the absence of one or another pathology, is as follows: a specialist, “armed” with a special neurological instrument, makes delicate tapping in the actual area. The result of this manipulation is the extension of the toes.

This manifestation, related to the pyramidal signs, is considered a deformation of the pyramidal path.

The Bekhterev reflex is named after the great Russian researcher V.M. Bekhterev, who designated it as the tarso-phalangeal reflex. This happened at the dawn of the twentieth century, at a congress of psychiatrists and neurologists who gathered in the northern capital of the Russian Empire from many countries of the world. Three years later, the German neurologist K. Mendel studied the dorsifoot manifestation. It was designated as the Bekhterev-Mendel reflex.

Is treatment possible?

Pathological reflexes in neurology themselves are not treated, since this is not a separate disease, but only a symptom of some mental disorder. They indicate problems with the functioning of the brain and nervous system. Therefore, it is necessary, first of all, to look for the reason for their appearance. Only after a doctor has made a diagnosis can we talk about specific treatment, because it is necessary to treat the cause itself, and not its manifestations. Pathological reflexes can only help in determining the disease and its severity.

How do problems appear?

In infancy, physiological reflexes arise and disappear at certain times. By the age of one year, most of them disappear. With various neurological disorders, the child’s reflexes are inhibited or, on the contrary, activated, and the timing of their onset and cessation also changes. Thus, deviations from the norm or, in other words, pathological reflexes are observed.

It should be noted that reflexes that are not lost in time continue to appear in subsequent years of the child’s life, appearing at a stage of development that is unusual for them. The nervous system records them along with newly acquired skills, which adversely affects the latter and inhibits the normal physiological development of the child. As a result, motor activity is impaired.

Movements in children and adults are developed through repeated repetition of actions. As previously noted, reflexes are necessary to regulate a child’s motor skills until conscious activity is formed. When moving into the category of pathological, they are recorded in the brain’s memory and thereby contribute to the distortion and sustainable formation of incorrect movements.