What is Hoffmann’s sign or Hoffmann’s Reflex?
Hoffmann’s
sign is a test for pathological disorder in upper motor neuron reflex as seen in cervical
myelopathy when the spinal cord in the cervical spine gets compressed and chances
are that the patient will exhibit pathological reflexes.
The Hoffmann’s sign is also known as a digital reflex, snapping reflex, Jacobson sign and trauma sign.
It clearly demonstrates
the lesion in the pyramidal tract even with asymmetric clinical findings along with
presence of different reflexes.
According to
Grivalja et.al from 2015 it has a sensitivity of 59 and a specificity of 49%.
How to Perform Hoffmann’s Sign Test
· The patient may be sitting or standing.
- support the patient's hand so that it is completely relaxed, with the fingers partially flexed.
- Hold the patient hand gently and firmly,
- Then grasp the patient's middle figure proximal to the distal interphalangeal joint.
- Then flick the patient's nail of the middle finger with your thumb.
- If the Hoffmann’s test is positive, you’re able to observe quick adduction of the thumb and flexion of the index finger.
- If the Hoffmann’s test is negative there will be no reflex.
Introduction of Hoffmann’s sign/ Reflex
It is one of indicative of hyperreflexia. It is also found in patients with hyperthyroidism anxiety another clinical and the pathological condition associated with deep tendon reflexes.
Furthermore,
in clinical practice, hyperthyroidism can be asymmetric cause of hyperreflexia
which could be supposed to cause bilateral findings whereas in some cases of
damage to the brain as in the case of tumour in the brain can cause unilateral findings. Thus,
it is concluded that the unilateral Hoffmann sign is more specific to structural
disease in patients.
Hoffmann’s
sign is also used to find cervical spinal disease in comparison to Babinski
sign, to check the severe neurological deficit and surgically treated patients
for cervical myelopathy, it is most preferred, as it is present in
almost all cases and is most likely to occur in patients which severe
neurological disorder.
Hoffmann’s sign is found to be a good indicative marker for different hidden cervical cord compression in a patient with lumbar spine disease without symptoms.
History of Hoffmann’s Sign
This reflex
of abduction of thumb and flexion of the index finger, when the middle finger is strike
aka Hoffmann's Reflex is attributed to German neurologist Johann Hoffmann
(1857-1919).
It was used
to demonstrate the lesion or disorder in the corticospinal tract.
In 1916,
Keyser reported a series of 35 neurological cases demonstrating the Hoffmann's
Reflex but he could not find any reference to Hoffmann's contribution.
Later on,
one of Hoffmann's resident Hons Curschmann (1875-1942) mentioned the reflex in
his footnote about neurological disorder in a 10-year-old child having acute
nephritis. In this, there was diminished biceps and triceps reflex bilaterally
and also find negative Hoffmann's phenomenon bilaterally. In his footnote he
further explained 'The Hoffmann's Reflex' that the examiner has to hold the
slightly bend finger of the patient between thumb and index finger and when
snapping in the nail of one of those fingers shows quick flexion of the same finger or
in all finger.
Kastein in
1930 stated that Hoffmann's sign is a normal test to check finger flexor muscles
stretch reflex.
Wartenberg,
the neurologist well known for his Wartenberg sign/ Wartenberg syndrome and
several other neurological disorder theories. Also stated that Hoffmann's sign
is based on the physiological mechanism of muscle stretch reflex. The flexor
compartment of finger muscles contracts those muscles when they are being
rapidly stretched.
Hoffmann’s sign and Myelopathy
Hoffmann
sign is associated with the lesion and disorder in the corticospinal tract. And
hence it is useful in the detection of several myelopathies.
Myelopathy
is a neurological deficit associated with spinal cord injury. It is of a different type.
- Acute Spinal Injury -caused by trauma,
- Myelitis -caused by inflammation response,
- Vascular Myelopathy -are those myelopathies which are vascular in nature.
In human
most common myelopathy is Cervical Spondylitis Myelopathy. It is mainly caused
by arthritic changes in the cervical region of the spinal cord which is also a result of
narrowing of the spinal canal known as Spinal Stenosis.
These
Myelopathies are mainly diagnosed by clinical exam findings. As Myelopathies
is a clinical syndrome so it can be a result of multiple pathologies. Because of
this, differential diagnosis is a must in these conditions.
The
diagnostic process of most of the myelopathies follows Magnetic Resonance
Imaging (MRI), X-ray and Computer tomography. Angiography is used in case of
Vascular Myelopathy. Sometimes Transcranial Magnetic Stimulation is used to
check the severity of myelopathies.
To add on
this Hoffmann’s Sign helps medical practitioner to detect the Cervical
Spondylitis Myelopathy for further clinical diagnosis.
Hoffmann’s sign and Multiple Sclerosis
Hoffmann’s sign
and Multiple sclerosis are co-related in a way that different myelopathy demonstrated
by Hoffmann’s sign is mainly caused by multiple sclerosis.
Multiple
sclerosis is a demyelinating disorder of neurons in which neuron loses its insulating
covering sheath due to its own body immune response which results in several
neurological deficit.
Multiple
Sclerosis is associated with different tracts in the body including corticospinal
tract whose lesion are demonstrated by Hoffmann’s sign.
Moreover,
the treatment and prognosis of myelopathies can be done by specific treatment
as per the cause which may also present with myelopathy.
And as
discussed above the most common form of myelopathy is secondary to degeneration
of the cervical spine, the Hoffmann’s Sign provide aid for its treatment and
prognosis.
Hoffmann’s Sign and Babinski Sign
Hoffmann
sign is associated with upper extremity just like Babinski sign. Since both of
the sign are associated with a lesion in the upper motor neuron of the corticospinal
tract, Hoffmann sign is more often confused with Babinski sign. However, both
of these reflexes are different and should not be confused.
Hoffmann’s
sign can be present in normal patient and is more commonly found in a patient
with normal hyperreflexia.
It shows
pathological disorder when it is positive along with the presence of asymmetric or
acute onset of reflex.
Hoffmann
sign is a deep tendon reflex which follows the monosynaptic reflex pathway in
lamina IX of the spinal cord.
Whereas Positive
Babinski sign demonstrates pathological condition in the spinal cord and brain.
It is not
demonstrated in a normal patient but sometimes the term ‘Negative Babinski sign’ is
used for them.
Babinski
sign is commonly known as plantar reflex. It does not flow monosynaptic pathway
rather it has complicated synaptic transmission.
Babinski
Sign is related to reflex in planter region (Lower Extremities) whereas
Hoffmann’s sign is related to reflex in the palmer region (Upper Extremities).
Summary
Hoffmann’s Sign
is one of the basic reflexes to trace the lesion in upper motor lesion
especially associated with corticospinal tract innervating the upper extremities.
It is also known as finger flexor reflex which shows quick adduction of thumb
and flexion of other fingers when the middle finger of the same hand is flicked on the nail.
It is more often
confused with Babinski Sign which also a neurological reflex involving
corticospinal tract.
It does not always show pathological disorder as it is also present in the normal person. Whereas it may indicate some of the upper motor lesion which requires further clinical lab testing.