Hoffmann's Sign

Introduction

Dr. Johann Hoffmann, a German neurologist, is credited with the discovery of the eponymous Hoffmann's sign or reflex.[1] Although his assistant, Dr. Hans Curschman, is responsible for the dissemination of this finding, leading to its universal use in neurological screening today.[2]

Technique

The following steps[3][4] should be followed while performing this test:

  1. Position the subject’s relaxed hand ensuring dorsiflexion at the wrist and partial flexion of the fingers.
  2. Hold the subject's partially extended middle finger between your index and middle finger, ensuring you stabilize the proximal IP joint.
  3. Perform a sharp and forceful flick of your thumb, making contact with the nail of the subject’s middle finger.
  4. The subject's finger will flex immediately followed by relaxation.
  5. The presence of Hoffmann's sign is characterized by flexion and adduction of the thumb and flexion of the index finger.
[5]

Interpretation

A positive Hoffmann's sign is suggestive of corticospinal tract dysfunction localized to the cervical segments of the spinal cord.[3] In this regard, it is analogous to the Babinski sign.

Conditions such as multiple sclerosis, hyperthyroidism, and anxiety will also result in a positive sign.[4]

Systemic disorders usually result in a bilateral response while structural anomalies such as tumors result in a unilateral response.[4]

It is worth noting that up to 3% of the population has been found with a positive sign without any indication of cord compression or UMNL disease.[6]

Psychometrics

While the solitary presence of Hoffmann's sign is inconclusive for the diagnosis of cervical myelopathy[7], a unilateral positive sign is more specific[8] and a bilateral positive finding is highly sensitive for confirmation of the same.[9] Nevertheless, MRI remains the gold standard for diagnosing cervical myelopathies.[7]

However, a study revealed that in subjects with degenerative cervical myelopathy, there is insufficient data to support its solitary use in confirming the diagnosis.[10]

References

  1. P Hoffmann. Über eine Methode, den Erfolg einer Nervennaht zu beurteilen. Medizinische Klinik, March 28, 1915b, 11 (13): 359-360.
  2. Bendheim, OL. "ON THE HISTORY OF HOFFMANN'S SIGN." Bulletin of the Institute of the History of Medicine 1937; 5(7): 684-86.
  3. 3.0 3.1 DeJong’s The Neurologic Examination: Sixth edition; Lippincott Williams and Wilkins 2005, pp 495-496.
  4. 4.0 4.1 4.2 Barman B. Clinical Sign Revisited: Hoffman’s sign. Indian J Med Spec 2010; 1(1):44-45
  5. CRTechnologies. Hoffmann's Sign Test (CR). Available from: https://www.youtube.com/watch?v=q_4gpNizwPg (accessed 19 August 2020)
  6. Whitney E, Munakomi S. Hoffmann Sign. StatPearls. 2020 Jan.
  7. 7.0 7.1 Fogarty A, Lenza E, Gupta G, Jarzem P, Dasgupta K, Radhakrishna M. A Systematic Review of the Utility of the Hoffmann Sign for the Diagnosis of Degenerative Cervical Myelopathy. Spine (Phila Pa 1976). 2018 Dec 1;43(23):1664-1669. doi: 10.1097/BRS.0000000000002697. PMID: 29668564.
  8. Bradley WG, Daroff RB, Fenichel GM, Jankovic J. Neurology in clinical practice, 5th edition, Elsevier, 2008, pp 362,427.
  9. Houten JK, Noce LA. Clinical correlation of cervical myelopathy and the Hoffman sign. J Neurosurg Spine 2008;9:237-42.
  10. Fogarty A, Lenza E, Gupta G, Jarzem P, Dasgupta K, Radhakrishna M. A systematic review of the utility of the Hoffmann sign for the diagnosis of degenerative cervical myelopathy. Spine. 2018 Dec 1;43(23):1664-9.