The hoffman sign It is an abnormal reflex response that consists of flexing the fingers of the hand when pressing the nail of the middle finger. Although it is generally associated with pathologies such as pyramidal syndrome, it can occur in healthy people who have heightened reflexes (which is called hyperreflexia)..
Apparently this sign usually indicates some damage to the spinal cord or brain. The clinical neurological examination had great importance in the past, when the technological developments of today's medicine did not exist. In it the reflexes were checked to observe the state of health of the person.
However, today, with neuroimaging techniques, these exams carry less weight when making clinical decisions.
The description of the Babinski reflex or plantar reflex in 1896 prompted neurologists to look for another type of reflex. The anatomical region in which reflexes were most investigated were the lower extremities.
The abnormal reflexes in the upper extremities were less constant, more difficult to obtain, and of less diagnostic significance. Although the Hoffman sign has been used for more than a hundred years to detect pathologies.
Its name comes from the German neurologist Johann Hoffman (1857-1919), who discovered it at the end of the 19th century. However, the one who first wrote about this sign was his assistant Curschmann in 1911.
The Hoffman and Tromner signs are the most used signs clinically regarding the upper extremities, to indicate problems in the corticospinal tract.
The Hoffman reflex is sometimes mistakenly called the "Babinski reflex of the upper limb." However, they are different reflections and should not be confused.
The Hoffman sign is also known as the digital reflex and was used as a test for corticospinal tract disease of the pyramidal pathway..
The presence of this reflex may indicate an involvement of the upper motor neurons that make up the pyramidal pathway. These neurons are responsible for the voluntary movements of the upper limbs.
When affected, in addition to the Hoffman sign, they produce other symptoms such as hypertonia (increased muscle tone), weakness, hyperreflexia, rhythmic and involuntary contractions of the muscles, or difficulties in making precise movements with the hands..
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To obtain the Hoffman sign, the patient's relaxed hand is grasped with the wrist flexed downward and the middle finger partially flexed. The examiner will hold the patient's middle finger by placing it between his index finger and his middle finger..
He will make a strong movement with his thumb, tapping or pinching the nail of the patient's middle finger. However, it can also be seen by tapping the nail of the index finger or ring finger..
Hoffman's sign is said to be present if thumb adduction and index finger flexion occur. Flexion of the remaining fingers is also sometimes present.
In addition, it has been observed that flexing or extending the neck can sometimes worsen this sign..
The Hoffman sign indicates damage to the corticospinal tract of the pyramidal tract. It is a set of nerve fibers that travel from the cerebral cortex to the spinal cord. Its function is to transmit nerve impulses to perform voluntary movements.
These damages can be bilateral or unilateral. When unilateral damage occurs, the side of the body opposite to where the injury is located is affected. Thus, this sign can appear in one hand or in both, depending on whether it is unilateral or bilateral..
The Hoffman sign indicates the presence of hyperreflexia. It accompanies a wide variety of conditions, such as hyperthyroidism, some types of anxiety, and other conditions related to deep tendon reflexes..
Hyperreflexia due to hyperthyroidism usually produces bilateral findings. While structural damage to the brain, such as a tumor, will lead to a one-sided reflex.
This sign is also used to evaluate diseases of the cervical spine. Compared with Babinski's sign, Hoffman's sign is more prevalent in patients who have been surgically treated for myelopathies..
Myelopathies are chronic disorders of the spinal cord. They usually refer to those that are not due to trauma or inflammation. Some authors indicate that the Hoffman sign is more likely in patients with less severe neurological problems.
Apparently, the Hoffman sign can also be an indicator of multiple sclerosis. It is seen when there has been injury to the motor nerve pathways or the spinal cord in the part of the nerves that control hand movements (such as C5).
In patients with lumbar spine disease, but without cervical spine-related symptoms, this sign is an indicator of hidden compression in the cervical spine..
However, in a study by Glaser, Cura, Bailey and Morrow (2001) that analyzed 165 patients with cervical spinal cord compression, they concluded that the Hoffman test is not a reliable tool to predict this condition..
Since they observed a significant incidence of the existence of the Hoffman sign in healthy people while they found patients with spinal compression who did not present this sign.
On the other hand, in a study by Sung and Wang (2001), asymptomatic patients with Hoffman's sign were studied. Cervical X-rays and MRI scans were performed on the 16 patients.
Magnetic resonance imaging reflected pathologies in all patients. Fourteen of them had cervical spondylosis. 15 had compression of the cord due to herniation of the nucleus pulposus. While one of them had a herniated disc at T5-T6, with its resulting compression.
It is important to mention that the Hoffman sign does not always indicate the existence of a pathology of the pyramidal tract. On some occasions it has been observed in people with "live" reflexes such as those who are suffering from anxiety or are under the effects of stimulant substances.
However, when accompanied by other pathological reflexes or abnormal symptoms, this sign implies some disease of the nervous system.
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