H-reflex
An electrically evoked reflex response used to assess the integrity of the monosynaptic reflex arc.
Full Definition
The Hoffmann reflex, or H-reflex, is a neurophysiological response obtained by electrical stimulation of sensory fibers in a mixed nerve, resulting in a reflex muscle contraction. Named after Paul Hoffmann, this test evaluates the monosynaptic reflex pathway including the sensory nerve, spinal cord connections, and motor nerve. The H-reflex is most commonly recorded from the soleus muscle by stimulating the tibial nerve. It is particularly useful for detecting S1 radiculopathy and assessing spinal cord function, as it bypasses the muscle spindle and directly tests the neural pathway.
Usage
Usage note: Always capitalize 'H' and hyphenate; distinguish from 'F-wave' which tests different neural pathways.
In Context
- "The H-reflex was absent bilaterally, suggesting S1 nerve root involvement." — Nerve conduction study report
- "H-reflex latencies were prolonged on the affected side compared to normative values." — Electrodiagnostic interpretation