Tracing of proximal lumbosacral nerve conduction – a comparison of simultaneous magneto – and electroneurography

• Published in: Clinical neurophysiology Vol. 112; no. 8; pp. 1408 - 1413
• Main Authors: Mackert, Bruno-Marcel, Burghoff, Martin, Hiss, Lars-Henning, Trahms, Lutz, Curio, Gabriel
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 01.08.2001; Elsevier Science
• Subjects: Adult; Biological and medical sciences; Electrodiagnosis. Electric activity recording; Electroneurography; Electrophysiology; Evoked Potentials; Humans; Investigative techniques, diagnostic techniques (general aspects); Lumbosacral nerve roots; Lumbosacral Plexus - physiology; Magnetic field; Magnetics; Magnetoneurography; Medical sciences; Nervous system; Neural Conduction - physiology; Spinal Nerve Roots - physiology; Superconducting quantum interference device; Surface potential; Magnetoneurography; Electroneurography; Magnetic field; Superconducting quantum interference device; Surface potential; Lumbosacral nerve roots; Peripheral nervous system; Human; Peripheral nerve; Central nervous system; Lumbosacral plexus; Nerve conduction; Electrodiagnosis; Electric field; Superconducting quantum interferometer device; Signal reconstruction; Somatosensory evoked potential
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/S1388-2457(01)00548-X

Objective: The reconstruction of nerve impulse conduction along proximal lumbosacral plexus and nerve roots is compared using simultaneous magneto- and electroneurography. Methods: In 3 healthy subjects the left tibial nerve was electrostimulated at the ankle. Evoked magnetic fields and electric surface potentials were measured simultaneously over the lumbosacral spine using a multichannel SQUID-detector with a planar measuring area and 25 surface electrodes covering a comparable area centered around L4. Based on either magnetic field or electric potential maps the depolarization front of the evoked compound action currents (CAC) was spatio-temporally reconstructed using a simple equivalent current dipole model in a half-space volume conductor. Results: The mean signal-to-noise ratio in the magnetic (electric) recordings was around 4 (8). Yet, the localization quality for the propagating CAC was lower for electric than magnetic recordings. The local nerve conduction velocity was around 47 m/s (calculated from magnetic data), but fluctuated unphysiologically for electric data. Conclusion: In comparison to electroneurography, an anatomically reasonable localization of evoked compound action currents propagating in lumbosacral roots can be obtained by magnetoneurography.