6533b7ddfe1ef96bd127467e

RESEARCH PRODUCT

The Hoffmann reflex of human plantar foot muscles

Heinz SteffensJens EllrichEike D. SchomburgRolf-d. Treede

subject

Soleus musclemedicine.diagnostic_testPhysiologybusiness.industryAnatomyElectromyographyF waveAnkle jerk reflexCellular and Molecular NeurosciencePhysiology (medical)ReflexMedicineAbductor hallucis muscleNeurology (clinical)H-reflexTibial nervebusiness

description

Electrical stimulation of the tibial nerve in the popliteal fossa evoked an M wave (10.9 ms) and a late reflex response (38.1 ms) in the plantar foot muscles of all 10 volunteers. The late response had a somewhat lower electrical threshold than the corresponding M wave (8.5 versus 9 mA), and reached a maximum of amplitude when the stimulus intensity was increased, but was strongly suppressed by further increased intensity. A more distal stimulation of the tibial nerve at the ankle shortened the onset latency of the M wave and lengthened that of the late response. The reflex was facilitated by activation of synergists and inhibited by activation of antagonists. We showed that the late response was contaminated neither by volume conducted activity from the soleus muscle, as shown by intramuscular recordings from the abductor hallucis muscle, nor by a F wave, as shown by double stimulation. In summary, we conclude that this late response in human plantar foot muscles corresponded to an H reflex, which may be used to assess alterations of distal motoneuronal excitability.

https://doi.org/10.1002/(sici)1097-4598(199806)21:6<732::aid-mus4>3.0.co;2-8