Reflex is the body's response to external stimuli. With a violation in the work of the brain or nervous system, pathological reflexes occur, which are manifested by the pathology of motor reactions. In neurological practice, they serve as beacons for identifying various diseases.
The concept of pathological reflex
With the defeat of the main neuron of the brain or neural pathways, 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 responds inadequately to physical contact, compared with a normal person without pathologies.
Such reflexes indicate any mental or neurological diseases in humans. In children, many reflexes are considered the norm (extensor-plantar, grasping, sucking), while in adults, the same are considered pathology. At the age of two years, all reflexes are due to the fragile nervous system. Both conditioned and unconditioned reflexes are pathological. The former appear as an inadequate response to the stimulus, fixed in the memory in the past. The latter are unusual in biological terms for a given age or situation.
Causes of occurrence
Pathological reflexes can be the result of damage to the brain, pathologies of the central nervous system, such as:
- damage to the cerebral cortex by infections, diseases of the spinal cord, tumor;
- hypoxia - brain functions are not performed due to lack of oxygen;
- stroke - damage to the 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 condition;
- consequences of injuries.
Any diseases of the nervous system, damage to neural connections, diseases of the brain can cause irregular, unhealthy reflexes.
Classification of pathological reflexes
Pathological reflexes are divided into the following groups:
- Reflexes of the upper limbs. This group includes carpal pathological reflexes, an unhealthy response to external stimuli of the upper extremities. May be manifested by involuntary capture and retention of the subject. They occur with irritation of the skin of the palms at the base of the fingers.
- 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.
- Oral muscle reflexes are a pathological contraction of the facial muscles.
Foot reflexes
Extensor reflexes of the foot are an early manifestation of damage to the nervous system. Babinsky's pathological reflex is most often tested in neurology. It is a sign of upper motor neuron syndrome. Refers to the group of reflexes of the lower extremities. It appears as follows: the dashed movement along the outer edge of the foot leads to the extension of the big toe. May be accompanied by a fan in the form of a fan of all toes. In the absence of pathology, such foot irritation leads to involuntary flexion of the thumb or all toes. Movement should be light, not causing pain. The reason for the formation of the Babinsky reflex is the delayed conduction of irritation along the motor channels and the violation of the excitation of segments of the spinal cord. In children under one and a half years of age, the manifestation of the Babinsky reflex is considered normal, then with the formation of gait and vertical position of the body, it should disappear.
A similar effect can occur with other effects on receptors:
- Oppenheim reflex - extension of the finger occurs when pressed and moved from top to bottom with the thumb of the hand in the tibia;
- Gordon's reflex - with compression of the calf muscle;
- Schaeffer reflex - with compression of the Achilles tendon.
Pathological flexion reflexes of the foot:
- Rossolimo reflex - when exposed to jerky blows of the malleus or fingertips along the inner surface of the phalanges, the II-V toes of the foot quickly bend;
- Ankylosing spondylitis - the same reaction occurs with light tapping on the outer surface of the foot in the metatarsal bones;
- Zhukovsky's reflex - manifests itself when striking the center of the foot, at the base of the fingers.
Oral automatism reflexes
Oral automatism is the reaction of the muscles of the mouth to an irritant, manifested by their involuntary movement. This kind of pathological reflexes are observed in the following manifestations:
- The nasolabial reflex occurs when a hammer is tapped at the base of the nose, and is manifested by lip extension. The same effect can occur when approaching the mouth (distal-oral reflex) or with light strokes on the lower or upper lip - the oral reflex.
- Palmar-chin reflex, or Marinescu-Radovic reflex. Dashed movements in the thumb area on the palm side cause the reaction of the facial muscles and cause the chin to move.
Such reactions are considered the norm only for infants, their presence in adults is a pathology.
Synkinesia and protective reflexes
Synkinesia is a reflex characterized by paired movement of the limbs. Pathological reflexes of this kind include:
- global synkinesia (when bending the arm, the leg extends or vice versa);
- imitation: involuntary repetition of the movements of an unhealthy (paralyzed) limb behind healthy movements;
- coordinating: spontaneous movements of an unhealthy limb.
Synkinesia automatically occurs with active movements. For example, when moving with a healthy hand or foot in a paralyzed limb, spontaneous muscle contraction occurs, a bending movement of the arm occurs, and an unbending motion of the legs.
Protective reflexes occur with irritation of a paralyzed limb and are manifested by its involuntary movement. The irritant may be, for example, a prick with a needle. Such reactions are also called spinal automatisms. The protective reflexes include the symptom of Marie-Foix-Bekhtereva - flexion of the toes leads to involuntary flexion of the leg in the knee and hip joint.
Tonic reflexes
Normally, tonic reflexes occur in children from birth to three months. Their ongoing manifestation and in the fifth month of life may indicate the defeat of the child cerebral palsy. In cerebral palsy, congenital motor automatisms do not die out, but continue to develop. These include pathological tonic reflexes:
- Labyrinth 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 an increased tone of the extensor muscles when standing on the back and flexors when the child is lying on his stomach.
- Symmetrical cervical tonic reflex. When cerebral palsy is manifested by the influence of head movements on muscle tone of limbs.
- Asymmetric cervical tonic reflex. It is manifested by an increase in muscle tone of the limbs when turning the head to the side. On the side where the face is turned, extensor muscles are activated, and on the back of the head, flexors.
With cerebral palsy, a combination of tonic reflexes is possible, which reflects the severity of the disease.
Tendon reflexes
Tendon reflexes are normally caused by a blow to the tendon. 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 an extension occurs upon impact.
- Knee-jerk reflex. The blow falls on the quadriceps femoris, under the patella. The result is leg extension in the knee joint.
Pathological tendon reflexes are manifested in the absence of a reaction to hammer blows. May occur with paralysis, coma, spinal cord injuries.
Is treatment possible?
Pathological reflexes in neurology alone are not treated, since this is not a separate disease, but just a symptom of some kind of mental disorder. They indicate problems with the functioning of the brain and nervous system. Therefore, we must first of all look for the cause of their appearance. Only after a diagnosis is made by a doctor can we talk about a specific treatment, because the cause itself must be treated, and not its manifestation. Pathological reflexes can only help in determining the disease and its severity.