Overview of Babinski reflex
The Babinski reflex is one of the normal reflexes in babies. Reflexes are replies that occur when the body receives a convinced stimulus.
The Babinski reflex happens after the sole of the foot has been firmly stroked. Then the big toe moves up or to the top surface of the foot. The other fingers fan out.
This reflex is normal in kids up to 2 years of age. It disappears as the child grows. It can disappear after 12 months.
Reflection-Babinski; Extensor plantar reflex; Babinski’s sign
Causes of Babinski reflex
When the Babinski reflex is current in a child older than 2 years or in an adult, it is often a sign of a central nervous system disorder. The dominant nervous system contains the brain and spinal cord. Disorders can include:
- Amyotrophic lateral sclerosis (Lou Gehrig’s disease)
- Brain tumor or injury
- Meningitis (infection of the skins that cover the brain and spinal cord)
- Multiple sclerosis
- Spinal cord injury, defect, or tumor
Indications of Babinski reflex
The Babinski reflex is performed as part of a routine neurological inspection and is used to determine the honesty of the CST. The presence of a Babinski sign suggests damage to the CST. Because the CST fiber tracts run from the brain, through the brainstem, and to the spinal cord, central nervous system (CNS) injuries often affect the integrity of the CST.
Thus, the presence or absence of the Babinski reflex can provide very useful information on the presence or absence of pathology that affects the CNS. The Babinski reflex is especially important in the setting in which a spinal cord injury or stroke is suspected, as it can be an early indicator of the presence of these emergency conditions.
Preparation for test
The patient must be relaxed and comfortable. It is best to warn the patient that the sensation may be slightly uncomfortable. Patients may experience a mildly unpleasant sensation and a tingly sensation. The examiner must ensure that the plantar surface of the foot is free from injury before proceeding.
Tests and results
To check the Babinski reflex, a doctor will use a blunt object, such as a tongue depressor. Before the test, they will make sure the person is relaxed and comfortable. They can warn the person about the sensation of the test, which can range from tickling to uncomfortable and unpleasant.
The doctor will then firmly stroke the sole of the foot with the object in a curved line, moving from the heel of the foot to the toes and up to the big toe. The standard response is automatic, causing the toes to flex toward pressure and stimulation. This normal response confirms that the Babinski reflex is absent.
The Babinski reflex occurs when the big toe extends toward the top of the foot. Simultaneously, the other toes are fanned out. If this occurs in response to the test, it means that the Babinski reflex is present. If nothing happens and there is no response, this is a neutral result. Therefore, the test is of no importance and doctors will move on to other testing methods.
Doctors will also look for the sign on both feet. A reflex that is current in one foot and absent in the other can help show which side of the nervous system the fundamental condition is affecting. The Babinski reflex is not infallible. With this test, it is possible to obtain false positives and negatives, especially if the technique is incorrect. For this reason, performing a Babinski reflex test at home is not reliable.
Other factors, such as someone having a lot of tickling on their feet, can also affect the test or make it difficult to complete correctly. Regardless of the test result, doctors will go ahead with other tests to continue their diagnosis. These may include other neurological or reflex tests, imaging, or blood tests.
When is a Babinski sign normal?
In a child younger than 2 years old, the big toe should bend up and back toward the top of the foot, while the other four toes fan out. This response is normal and does not indicate a problem or abnormality.
In a child older than 2 years or in a mature adult, the Babinski sign must be absent. All five toes should be flexed or curved downward as if they are trying to grasp something. If this test is done on a child older than 2 years or an adult and the toes answer like those of a child younger than 2 years, this may indicate an underlying neurological problem.
When is a Babinski sign abnormal?
In a child younger than 2 years old born with intellectual disabilities or other mental illnesses, the Babinski reflex can persist for an abnormally long period of time. In a child younger than 1 to 2 years old who is born with any condition that causes spasticity (muscle spasms and stiffness), the Babinski reflex may appear weak when the doctor strokes the baby’s foot, or it may not occur at all.
In adults or children older than 2 years, a positive Babinski’s sign occurs when the big toe bends up and back to the top of the foot and the other toes fan out. This may mean that you may have an underlying brain or nervous system condition that causes your reflexes to react abnormally.