Babinski's reflex in infants is a normal physiological symptom. In turn, in adults, it indicates many, sometimes dangerous, diseases. What is Babinski's positive and negative reflex?
Babinski's reflexis one of the most important neurological reflexes. It consists in the isolated movement of the extensor of the big toe or the simultaneous abduction of other toes while irritating the outer edge of the sole of the foot. Babinski's reflex may appear in one or both feet.
What is Babinski's reflex?
Babinski's reflex works well by irritating the foot with a sharp, hard object. The irritation should not cause pain as it may lead to the activation of pain receptors and withdrawal of the foot.
The natural reaction of the body to a slight irritation of the foot is to bend all the toes of the foot downwards - this is the so-called negative Babinski reflex. However, sometimes the body reacts to this type of stimuli by straightening the big toe and its dorsal flexion - this is the so-called positive Babinski reflex.
Some people also have the plantar reflex of the remaining fingers, i.e. bending them downwards, fan spacing or bending the lower limb in three joints.
History of Babinski's reflex
Józef Babiński is a French neurologist of Polish origin who is considered a co-founder of the foundations of neurology. It was he who, in 1896, described the pathological foot reflex that indicates damage to the central nervous system.
Two years later, he published a detailed description of it. Babinski's reflex is considered to be one of the most important skin neurological reflexes.
Babinski's reflex - positive and negative
The most common reaction to slight irritation of the foot skin is Babinski's negative reaction. Then all the toes of the foot undergo plantar flexion. This is a momentary reaction that shouldn't turn into a cramped and persistent flexion of the fingers.
Negative, otherwise absent Babinski'sreflex, is considered a normal response in adults, and the mutually absent one indicates no abnormalities in the functioning of the nervous system.
We speak of Babinski's positive reflexwhenthe big toe undergoes dorsiflexion, i.e. it bends upwards. Additionally, plantar flexion of the toes may appear. A positive symptom in adults informs about the presence of a disease entity.
The reflex can be one-sided or two-sided, and the one-sided reflex makes it easier to locate changes within the nervous system. Importantly, Babinski's positive reaction in children does not have to mean he alth problems.
However, some people do not develop any reflexes in response to the irritation of the foot. When the fingers do not bend to one side or the other, we say that Babinski's reflex is abolished. We can encounter such a situation in people with disorders or complete loss of sensation in the foot, e.g. in the course of polyneuropathy.
Occasionally, the abrogation of a reflex may be due to the irritation of the lower limbs, which often occurs after a stroke.
Causes of Babinski's positive reflex
Although in children Babinski's reflex should not be a cause for concern, in adults it is always treated as an abnormality. In the case of a positive reflex in adults, damage to the central nervous system should be suspected. It is observed in the event of damage to the pyramidal nervous system.
The causes of the positive Babinski reflex include:
- tumor of the brain or meninges,
- stroke,
- multiple sclerosis,
- amyotrophic lateral sclerosis,
- head injuries,
- epilepsy.
Diagnosis and treatment of Babinski's reflex
The diagnosis of Babinski's reflex is not difficult. The diagnosis is made by a neurologist during a standard neurological examination. To induce a symptom, the doctor drags a hard object over the skin on the foot, from the heel to the base of the little toe.
The test should not cause pain, but to be reliable, it must be felt by the patient. After finding an abnormality, it is most important to determine its cause, and detailed diagnosis is necessary to start treatment.
For this purpose, imaging tests should be performed, e.g. computed tomography and detailed laboratory tests (including more specialized ones, e.g. analysis of the cerebrospinal fluid).
Babinski's reflex in children
A newborn is born with reflexes that are reactions to external stimuli. The nervous system of young children is not yet fully developed, and thus the appearance of Babinski's reflex is not a cause for concern. It usually disappears after the first few months of life.
Researchers of Babinski's reflex to 18.month of life they treat as a normal, physiological reaction of the body. Some people push this limit even up to 3 years. However, in children over 3 years of age, Babinski's reflex may indicate a dysfunction of the pyramidal system.