Paul Hoffmann

Biography

• Born July 1, 1884 in Dorpat, Russian Empire, now Tartu, Estonia
• 1905-1909 – Studied medicine at the Universities of Leipzig, Marburg, and Berlin
• 1909-1911 – Assistant, Institute for Physiology, University of Berlin
• 1910 – Began early electrophysiological studies of human reflexes and muscle action potentials. Described the electrically evoked reflex response later named the Hoffmann reflex / H-reflex.
• 1911 – Appointed assistant to Max von Frey (1852–1932) at the Institute for Physiology, University of Würzburg
• 1912 – Became Privatdozent in physiology at Würzburg
• 1913 – Visited the United Kingdom, worked with Sir Charles Scott Sherrington (1857-1952)
• 1914–1918 – Served during the First World War in German field hospitals in France and at military hospitals in Würzburg. His observations of wounded soldiers with regenerating peripheral nerves led to his description of percussion-induced radiating paraesthesia.
• 1915 – Published two papers in Medizinische Klinik describing a method for early assessment of nerve repair and regeneration
• 1917 – Associate Professor extraordinarius, Policlinic of Internal Medicine at Würzburg
• 1924 – Appointed Director of the Institute for Physiology, University of Freiburg im Breisgau. Held the Freiburg chair/directorship until retirement. During this period he collaborated closely with Robert Wartenberg (1887–1956), who headed the nerve clinic until fleeing Nazi Germany in 1935
• 1932 – Reportedly protested restrictions on Jewish students attending lectures
• 1944 (November) – Freiburg Institute for Physiology destroyed in an air raid. Continued work in provisional accommodation and later in a new institute
• 1952–1953 – Nominated three times for the Nobel Prize in Physiology or Medicine
• 1954 – Retired from the University of Freiburg im Breisgau
• 1961 – Awarded honorary doctorates from the Universities of Berlin and Zürich
• Died on March 9, 1962

---

Medical Eponyms

Hoffmann-Tinel sign (Tinel sign) (1915)

The Hoffmann–Tinel sign is paraesthesia or tingling radiating into the distal sensory distribution of an injured or compressed peripheral nerve, elicited by percussion or pressure over the nerve. Hoffmann used the sign to assess early regeneration after nerve injury or nerve suture, before motor recovery was clinically evident.

1915 – While treating wounded soldiers during the First World War, Hoffmann observed that percussion over injured or regenerating peripheral nerves produced a tingling sensation radiating into the sensory territory of that nerve. He published his first account in Medizinische Klinik in March 1915, followed by a second paper in August 1915 refining the method.

Later in October 1915, Jules Tinel (1879-1952) independently described the same phenomenon as Le signe du ‘fourmillement’ in peripheral nerve lesions. Hoffmann and Tinel were apparently unaware of each other’s work, likely because of wartime disruption of scientific communication.

Hoffmann interpreted the sign as evidence of newly formed, mechanically hypersensitive regenerating nerve fibres. The key clinical observation was not only the presence of tingling, but whether the point of elicited paraesthesia progressed distally along the nerve, suggesting advancing regeneration. Failure of distal progression, or a sign fixed at the lesion or suture site, could suggest rupture, obstructing neuroma, or failed repair.

The sign later became widely applied to entrapment neuropathies, especially carpal tunnel syndrome, but also cubital tunnel syndrome, tarsal tunnel syndrome, Guyon canal syndrome, radial nerve entrapment, and other focal neuropathies. Modern studies report variable sensitivity and generally higher specificity; a negative sign does not exclude compression neuropathy.

---

Hoffmann reflex (1910; named 1950)

The Hoffmann reflex, or H-reflex, is an electrically evoked monosynaptic reflex response, similar to the mechanically elicited tendon stretch reflex. Hoffmann first described the electrophysiological basis of this response in 1910 while working with Hans Piper at the Physiological Institute in Berlin.

1910 – Hoffmann published Beiträge zur Kenntnis der menschlichen Reflexe mit besonderer Berücksichtigung der elektrischen Erscheinungen. Working at the Physiological Institute of the University of Berlin, he used a string galvanometer to record the electrical activity of human muscle following mechanical and electrical stimulation of tendon reflexes.

By stimulating the tibial nerve in the popliteal fossa and recording from the gastrocnemius–soleus muscle group, Hoffmann demonstrated two responses 1) an early direct muscle response and 2) a later reflex response. The early direct response corresponds to the modern M-wave and the later response the Hoffmann reflex, or H-reflex.

Hoffmann measured Achilles reflex latencies of approximately 31–36 ms with tendon percussion, and shorter latencies when the reflex was elicited electrically from the nerve. His summary gave electrical reflex times of 0.019–0.024 s for the patellar reflex and 0.032–0.036 s for the Achilles tendon reflex; with nerve stimulation these decreased to 0.017 s and 0.028 s, respectively.

The H-reflex is an electrically evoked analogue of the spinal stretch reflex. Modern interpretation describes stimulation of Ia afferent fibres, synaptic activation of alpha motor neurons in the spinal cord, and an efferent motor response recorded from muscle. It remains a clinical and research tool for assessing spinal reflex excitability, especially in the S1 reflex arc, motor control, reciprocal inhibition, and neuromuscular rehabilitation research.

1922 – Hoffmann further developed the concept of the monosynaptic / two-neuron tendon reflex in his monograph Untersuchungen über die Eigenreflexe (Sehnenreflexe) menschlicher Muskeln. His work on human tendon reflexes, monosynaptic reflex transmission, and post-reflex inhibitory phenomena has since been related to the EMG silent period or cutaneous silent period.

1950 – The reflex was eponymously named the Hoffmann reflex by J. W. Magladery and D. B. McDougal Jr, recognising Hoffmann’s earlier work on electrically elicited tendon reflexes.

Clinically, the H-reflex is useful as a measure of spinal reflex excitability, Ia afferent transmission, and alpha motor neuron pool responsiveness. It is associated with assessment of S1 radiculopathy, peripheral neuropathy, dystonia, motor control, and sports medicine research.

---

Major Publications

• Hoffmann P. Beiträge zur Kenntnis der menschlichen Reflexe mit besonderer Berücksichtigung der elektrischen Erscheinungen. Archiv für Physiologie 1910: 223-246 [Hoffmann Reflex]
• Hoffmann P. Über eine Methode, den Erfolg einer Nervennaht zu beurteilen. [Translation: Concerning a method for assessing the success of a nerve suture] Medizinische Klinik, 1915; 11: 359-360 [Hoffmann-Tinel Sign]
• Hoffmann P. Weiteres über das Verhalten frisch regenerierter Nerven und über eine Methode, den Erfolg einer Nervennaht frühzeitig zu beurteilen. [Additional findings regarding nerve regeneration and the method of early evaluation of the success of nerve repair]. Medizinische Klinik. 1915; 11: 856-858. [Hoffmann-Tinel Sign]
• Hoffmann P. Untersuchungen über die Eigenreflexe (Sehnenreflexe) menschlicher Muskeln. 1922

---

Controversies

Hoffmann-Tinel-sign

• March 1915 – Paul Hoffmann observed the progress of nerve regeneration by tapping over the carpal tunnel. Hoffman described his test in relation to a single soldier with radial nerve (nervus musculospiralis) injury.
• October 1915 – Jules Tinel, observed the progress of nerve regeneration after gunshot wounds by pressing over the carpal tunnel. Tinel described “Le signe du Fourmillement” in numerous injured nerves

Note: The Hoffmann sign, or Hoffmann reflex relates to Johann Hoffmann (1857-1919)

---

References

Biography

• Jung R. Paul Hoffmann 1884-1962. Ergeb Physiol. 1969; 61 :1-17.

Eponymous terms

• Magladery JW, McDougal DB Jr. Electrophysiological studies of nerve and reflex activity in normal man. I. Identification of certain reflexes in the electromyogram and the conduction velocity of peripheral nerve fibers. Bull Johns Hopkins Hosp. 1950 May;86(5):265-90.
• Hoffmann P, Buck-Gramcko D, Lubahn JD. The Hoffmann-Tinel sign. 1915. J Hand Surg Br. 1993; 18(6): 800-5
• Koehler PJ, Bruyn GW, Pearce JMS. The Hoffmann-Tinel Sign. Neurological Eponyms. 2000: 136-143
• Palmieri RM, Ingersoll CD, Hoffman MA. The hoffmann reflex: methodologic considerations and applications for use in sports medicine and athletic training research. J Athl Train. 2004 Jul;39(3):268-77.
• Sansone JM, Gatzke AM, Aslinia F, Rolak LA, Yale SH. Jules Tinel (1879–1952) and Paul Hoffmann (1884–1962). Clin Med Res. 2006; 4(1): 85–89.
• Lücking C. 100 Jahre H-Reflex – eine Erinnerung an den Physiologen Paul A. Hoffmann (1884-1962). Klinische Neurophysiologie. 2007;38(4):241-243
• Koehler PJ. Publications on Peripheral Nerve Injuries during World War I: A Dramatic Increase in Knowledge. In: Frontiers of Neurology and Neuroscience. S. Karger AG; 2016:43-55
• Turgut AÇ, Tubbs RS, Turgut M. Paul Hoffmann (1884-1962 AD) and Jules Tinel (1879-1952 AD), and their legacy to neuroscience: the Hoffmann-Tinel sign. Childs Nerv Syst. 2019; 35(5): 733-734.
• Fustes OJH, Kay CSK, Lorenzoni PJ, Ducci RD, Rodrigues PRDVP, Scola RH. Paul Hoffmann and the cutaneous silent period test. Arq Neuropsiquiatr. 2025 May;83(5):1-3.
• Cadogan O. Clinical Signs in Carpal Tunnel Syndrome. LITFL
• Carpal Tunnel Exam. Stanford Medicine 25